Analyte                                  CAS No.     MDL \2\ (ng/L)   ML \3\ (ng/L)
----------------------------------------------------------------------------------------------------------------
Aldrin..........................................................        309-00-2               8              24
alpha-BHC.......................................................        319-84-6               6              18
beta-BHC........................................................        319-85-7               7              21
delta-BHC.......................................................        319-86-8               5              15
gamma-BHC (Lindane).............................................         58-89-9               1              33
alpha-Chlordane.................................................       5103-71-9               9              27
gamma-Chlordane.................................................       5103-74-2               8              24
4,4'-DDD........................................................         72-54-8               5              15
4,4'-DDE........................................................         72-55-9              10              30
4,4'-DDT........................................................         50-29-3              12              36
Dieldrin........................................................         60-57-1               6              18
Endosulfan I....................................................        959-98-8              11              33
Endosulfan II...................................................      33213-65-9               8              24
Endosulfan sulfate..............................................       1031-07-8               7              21
Endrin..........................................................         72-20-8               4              12
Endrin aldehyde.................................................       7421-93-4              11              33
Heptachlor......................................................         76-44-8               5              15
Heptachlor epoxide..............................................       1024-57-3              12              36
----------------------------------------------------------------------------------------------------------------
\1\ All analytes in this table are Priority Pollutants (40 CFR part 423, appendix A).
\2\ 40 CFR 136, Appendix B. MDLs were obtained by a single laboratory with an electrolytic conductivity
  detector, and are estimates of what can be achieved using an electron capture detector.
\3\ ML = Minimum Level--see Glossary for definition and derivation.

                                          Table 2--Additional Analytes
----------------------------------------------------------------------------------------------------------------
                             Analyte                                  CAS No.     MDL \3\ (ng/L)   ML \4\ (ng/L)
----------------------------------------------------------------------------------------------------------------
Acephate........................................................      30560-19-1           2,000           6,000
Alachlor........................................................      15972-60-8              20              60
Atrazine........................................................       1912-24-9             500           1,500
Benfluralin (Benefin)...........................................       1861-40-1              20              60
Bromacil........................................................        314-40-9              70             210
Bromoxynil octanoate............................................       1689-99-2              30              90
Butachlor.......................................................      23184-66-9              30              90
Captafol........................................................       2425-06-1             100             300
Captan..........................................................        133-06-2             100             300
Carbophenothion (Trithion)......................................        786-19-6              50             150
Chlorobenzilate.................................................        510-15-6              25              75
Chloroneb (Terraneb)............................................       2675-77-6  ..............  ..............
Chloropropylate (Acaralate).....................................       5836-10-2  ..............  ..............
Chlorothalonil..................................................       1897-45-6              15              45
Cyanazine.......................................................      21725-46-2  ..............  ..............
DCPA (Dacthal)..................................................       1861-32-1               3               9
2,4'-DDD........................................................         53-19-0  ..............  ..............
2,4'-DDE........................................................       3424-82-6  ..............  ..............
2,4'-DDT........................................................        789-02-6  ..............  ..............
Diallate (Avadex)...............................................       2303-16-4              45             135
1,2-Dibromo-3-chloropropane (DBCP)..............................         96-12-8  ..............  ..............
Dichlone........................................................        117-80-6  ..............  ..............
Dichloran.......................................................         99-30-9  ..............  ..............
Dicofol.........................................................        115-32-2  ..............  ..............
Endrin ketone...................................................      53494-70-5               8              24
Ethalfluralin (Sonalan).........................................      55283-68-6               5              15
Etridiazole.....................................................       2593-15-9  ..............  ..............
Fenarimol (Rubigan).............................................      60168-88-9              20              30
Hexachlorobenzene \1\...........................................        118-74-1  ..............  ..............
Hexachlorocyclopentadiene \1\...................................         77-47-4  ..............  ..............
Isodrin.........................................................        465-73-6              13              39
Isopropalin (Paarlan)...........................................      33820-53-0              20              60
Kepone..........................................................        143-50-0             100             300
Methoxychlor....................................................         72-43-5              30              90
Metolachlor.....................................................      51218-45-2  ..............  ..............
Metribuzin......................................................      21087-64-9               5              15
Mirex...........................................................       2385-85-5               4              12
Nitrofen (TOK)..................................................       1836-75-5              13              39
cis-Nonachlor...................................................       5103-73-1  ..............  ..............
trans-Nonachlor.................................................      39765-80-5  ..............  ..............
Norfluorazon....................................................      27314-13-2              50             150

Octachlorostyrene...............................................      29082-74-4  ..............  ..............
Oxychlordane....................................................      27304-13-8  ..............  ..............
PCNB (Pentachloronitrobenzene)..................................         82-68-8               6              18
Pendamethalin (Prowl)...........................................      40487-42-1  ..............  ..............
cis-Permethrin..................................................      61949-76-6             200             600
trans-Permethrin................................................      61949-77-7             200             600
Perthane (Ethylan)..............................................         72-56-0  ..............  ..............
Propachlor......................................................       1918-16-7  ..............  ..............
Propanil........................................................        709-98-8  ..............  ..............
Propazine.......................................................        139-40-2  ..............  ..............
Quintozene......................................................         82-68-8  ..............  ..............
Simazine........................................................        122-34-9             400           1,200
Strobane........................................................       8001-50-1  ..............  ..............
Technazene......................................................        117-18-0  ..............  ..............
Technical Chlordane \2\.........................................  ..............  ..............  ..............
Terbacil........................................................       5902-51-2             200             600
Terbuthylazine..................................................       5915-41-3             300             900
Toxaphene \1\...................................................       8001-35-2             910           2,730
Trifluralin.....................................................       1582-09-8              50             150
PCB-1016 \1\....................................................      12674-11-2             150             450
PCB-1221 \1\....................................................      11104-28-2             150             450
PCB-1232 \1\....................................................      11141-16-5             150             450
PCB-1242 \1\....................................................      53469-21-9             150             450
PCB-1248 \1\....................................................      12672-29-6             150             450
PCB-1254 \1\....................................................      11097-69-1             150             450
PCB-1260 \1\....................................................      11096-82-5             140             420
----------------------------------------------------------------------------------------------------------------
\1\ Priority Pollutants (40 CFR part 423, appendix A).
\2\ Technical Chlordane may be used in cases where historical reporting has only been for this form of
  Chlordane.
\3\ 40 CFR part 136, appendix B. MDLs were obtained by a single laboratory with an electrolytic conductivity
  detector, and are estimates of what can be achieved using an electron capture detector.
\4\ ML = Minimum Level--see Glossary for definition and derivation.

                  Table 3--Example Retention Times \1\
------------------------------------------------------------------------
                                                    Retention time (min)
                                                             \2\
                      Analyte                      ---------------------
                                                      DB-608    DB-1701
------------------------------------------------------------------------
Acephate..........................................       5.03      (\3\)
Trifluralin.......................................       5.16       6.79
Ethalfluralin.....................................       5.28       6.49
Benfluralin.......................................       5.53       6.87
Diallate-A........................................       7.15       6.23
Diallate-B........................................       7.42       6.77
alpha-BHC.........................................       8.14       7.44
PCNB..............................................       9.03       7.58
Simazine..........................................       9.06       9.29
Atrazine..........................................       9.12       9.12
Terbuthylazine....................................       9.17       9.46
gamma-BHC (Lindane)...............................       9.52       9.91
beta-BHC..........................................       9.86      11.90
Heptachlor........................................      10.66      10.55
Chlorothalonil....................................      10.66      10.96
Dichlone..........................................      10.80      (\4\)
Terbacil..........................................      11.11      12.63
delta-BHC.........................................      11.20      12.98
Alachlor..........................................      11.57      11.06
Propanil..........................................      11.60      14.10
Aldrin............................................      11.84      11.46
DCPA..............................................      12.18      12.09
Metribuzin........................................      12.80      11.68
Triadimefon.......................................      12.99      13.57
Isopropalin.......................................      13.06      13.37
Isodrin...........................................      13.47      11.12
Heptachlor epoxide................................      13.97      12.56
Pendamethalin.....................................      14.21      13.46
Bromacil..........................................      14.39      (\3\)
alpha-Chlordane...................................      14.63      14.20
Butachlor.........................................      15.03      15.69
gamma-Chlordane...................................      15.24      14.36
Endosulfan I......................................      15.25      13.87
4,4'-DDE..........................................      16.34      14.84
Dieldrin..........................................      16.41      15.25
Captan............................................      16.83      15.43
Chlorobenzilate...................................      17.58      17.28
Endrin............................................      17.80      15.86
Nitrofen (TOK)....................................      17.86      17.47
Kepone............................................      17.92      (3 5)
4,4'-DDD..........................................      18.43      17.77
Endosulfan II.....................................      18.45      18.57
Bromoxynil octanoate..............................      18.85      18.57
4,4'-DDT..........................................      19.48      18.32
Carbophenothion...................................      19.65      18.21
Endrin aldehyde...................................      19.72      19.18
Endosulfan sulfate................................      20.21      20.37
Captafol..........................................      22.51      21.22
Norfluorazon......................................      20.68      22.01
Mirex.............................................      22.75      19.79
Methoxychlor......................................      22.80      20.68
Endrin ketone.....................................      23.00      21.79
Fenarimol.........................................      24.53      23.79
cis-Permethrin....................................      25.00      23.59
trans-Permethrin..................................      25.62      23.92
PCB-1242..........................................
PCB-1232..........................................
PCB-1016..........................................
PCB-1221..........................................
PCB-1248..........................................
PCB-1254..........................................
PCB-1260 (5 peaks)................................      15.44      14.64
                                                        15.73      15.36
                                                        16.94      16.53
                                                        17.28      18.70
                                                        19.17      19.92
Toxaphene (5 peaks)...............................      16.60      16.60
                                                        17.37      17.52
                                                        18.11      17.92
                                                        19.46      18.73
                                                        19.69      19.00
------------------------------------------------------------------------
\1\ Data from EPA Method 1656 (Reference 16).
\2\ Columns: 30-m long x 0.53-mm ID fused-silica capillary; DB-608, 0.83
  [mu]m; and DB-1701, 1.0 [mu]m.
Conditions suggested to meet retention times shown: 150 [deg]C for 0.5
  minute, 150-270 [deg]C at 5 [deg]C/min, and 270 [deg]C until trans-
  Permethrin elutes.
Carrier gas flow rates approximately 7 mL/min.
\3\ Does not elute from DB-1701 column at level tested.
\4\ Not recovered from water at the levels tested.
\5\ Dichlone and Kepone do not elute from the DB-1701 column and should
  be confirmed on DB-5.

                                                             Table 4--QC Acceptance Criteria
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Calibration          Test
                           Analyte                              verification    concentration    Limit for s   Range for X   Range for P   Maximum  MS/
                                                                    (%)           ([mu]g/L)        (% SD)          (%)           (%)        MSD RPD (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aldrin......................................................           75-125              2.0            25        54-130        42-140              35
alpha-BHC...................................................           69-125              2.0            28        49-130        37-140              36
beta-BHC....................................................           75-125              2.0            38        39-130        17-147              44
delta-BHC...................................................           75-125              2.0            43        51-130        19-140              52
gamma-BHC...................................................           75-125              2.0            29        43-130        32-140              39
alpha-Chlordane.............................................           73-125             50.0            24        55-130        45-140              35
gamma-Chlordane.............................................           75-125             50.0            24        55-130        45-140              35
4,4'-DDD....................................................           75-125             10.0            32        48-130        31-141              39
4,4'-DDE....................................................           75-125              2.0            30        54-130        30-145              35
4,4'-DDT....................................................           75-125             10.0            39        46-137        25-160              42
Dieldrin....................................................           48-125              2.0            42        58-130        36-146              49
Endosulfan I................................................           75-125              2.0            25        57-141        45-153              28
Endosulfan II...............................................           75-125             10.0            63        22-171         D-202              53
Endosulfan sulfate..........................................           70-125             10.0            32        38-132        26-144              38
Endrin......................................................            5-125             10.0            42        51-130        30-147              48
Heptachlor..................................................           75-125              2.0            28        43-130        34-140              43
Heptachlor epoxide..........................................           75-125              2.0            22        57-132        37-142              26
Toxaphene...................................................           68-134             50.0            30        56-130        41-140              41
PCB-1016....................................................           75-125             50.0            24        61-103        50-140              36
PCB-1221....................................................           75-125             50.0            50        44-150        15-178              48
PCB-1232....................................................           75-125             50.0            32        28-197        10-215              25
PCB-1242....................................................           75-125             50.0            26        50-139        39-150              29
PCB-1248....................................................           75-125             50.0            32        58-140        38-158              35
PCB-1254....................................................           75-125             50.0            34        44-130        29-140              45
PCB-1260....................................................           75-125             50.0            28        37-130         8-140              38
--------------------------------------------------------------------------------------------------------------------------------------------------------
S = Standard deviation of four recovery measurements (Section 8.2.4).
Note: These criteria were developed from data in Table 5 (Reference 2). Where necessary, limits for recovery have been broadened to assure applicability
  to concentrations below those in Table 5.

                          Table 5--Precision and Recovery as Functions of Concentration
----------------------------------------------------------------------------------------------------------------
                                                                              Single analyst        Overall
                        Analyte                             Recovery, X'      precision, sr'     precision, S'
                                                             ([mu]g/L)          ([mu]g/L)          ([mu]g/L)
----------------------------------------------------------------------------------------------------------------
Aldrin.................................................       0.81C + 0.04     0.16(X) - 0.04     0.20(X) - 0.01
alpha-BHC..............................................       0.84C + 0.03     0.13(X) + 0.04     0.23(X) - 0.00
beta-BHC...............................................       0.81C + 0.07     0.22(X) - 0.02     0.33(X) - 0.05
delta-BHC..............................................       0.81C + 0.07     0.18(X) + 0.09     0.25(X) + 0.03
gamma-BHC (Lindane)....................................       0.82C - 0.05     0.12(X) + 0.06     0.22(X) + 0.04
Chlordane..............................................       0.82C - 0.04    0.13 (X) + 0.13     0.18(X) + 0.18
4,4'-DDD...............................................       0.84C + 0.30     0.20(X) - 0.18     0.27(X) - 0.14
4,4'-DDE...............................................       0.85C + 0.14     0.13(X) + 0.06     0.28(X) - 0.09
4,4'-DDT...............................................       0.93C - 0.13     0.17(X) + 0.39     0.31(X) - 0.21
Dieldrin...............................................       0.90C + 0.02     0.12(X) + 0.19     0.16(X) + 0.16
Endosulfan I...........................................       0.97C + 0.04     0.10(X) + 0.07     0.18(X) + 0.08
Endosulfan II..........................................       0.93C + 0.34     0.41(X) - 0.65     0.47(X) - 0.20
Endosulfan sulfate.....................................       0.89C - 0.37     0.13(X) + 0.33     0.24(X) + 0.35
Endrin.................................................       0.89C - 0.04     0.20(X) + 0.25     0.24(X) + 0.25
Heptachlor.............................................       0.69C + 0.04     0.06(X) + 0.13     0.16(X) + 0.08
Heptachlor epoxide.....................................       0.89C + 0.10     0.18(X) - 0.11     0.25(X) - 0.08
Toxaphene..............................................       0.80C + 1.74     0.09(X) + 3.20     0.20(X) + 0.22
PCB-1016...............................................       0.81C + 0.50     0.13(X) + 0.15     0.15(X) + 0.45
PCB-1221...............................................       0.96C + 0.65     0.29(X) - 0.76     0.35(X) - 0.62
PCB-1232...............................................       0.91C + 10.8     0.21(X) - 1.93     0.31(X) + 3.50
PCB-1242...............................................       0.93C + 0.70     0.11(X) + 1.40     0.21(X) + 1.52
PCB-1248...............................................       0.97C + 1.06     0.17(X) + 0.41     0.25(X) - 0.37
PCB-1254...............................................       0.76C + 2.07     0.15(X) + 1.66     0.17(X) + 3.62
PCB-1260...............................................       0.66C + 3.76     0.22(X) - 2.37     0.39(X) - 4.86
----------------------------------------------------------------------------------------------------------------
X' = Expected recovery for one or more measurements of a sample containing a concentration of C, in [mu]g/L.

      Table 6--Distribution of Chlorinated Pesticides and PCBs Into
                    Florisil[supreg] Column Fractions
------------------------------------------------------------------------
                                                     Percent recovery by
                                                         fraction \1\
                      Analyte                       --------------------
                                                       1      2      3
------------------------------------------------------------------------
Aldrin.............................................    100
alpha-BHC..........................................    100
beta-BHC...........................................     97
delta-BHC..........................................     98
gamma-BHC (Lindane)................................    100
Chlordane..........................................    100
4,4'-DDD...........................................     99
4,4'-DDE...........................................  .....     98
4,4'-DDT...........................................    100
Dieldrin...........................................      0    100
Endosulfan I.......................................     37     64  .....
Endosulfan II......................................      0      7     91
Endosulfan sulfate.................................      0      0    106
Endrin.............................................      4     96
Endrin aldehyde....................................      0     68     26
Heptachlor.........................................    100
Heptachlor epoxide.................................    100
Toxaphene..........................................     96
PCB-1016...........................................     97
PCB-1221...........................................     97
PCB-1232...........................................     95      4
PCB-1242...........................................     97
PCB-1248...........................................    103
PCB-1254...........................................     90
PCB-1260...........................................
------------------------------------------------------------------------
\1\ Eluant composition:
Fraction 1--6% ethyl ether in hexane
Fraction 2--15% ethyl ether in hexane
Fraction 3--50% ethyl ether in hexane.

BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TP19FE15.010

[GRAPHIC] [TIFF OMITTED] TP19FE15.011

23. Glossary
    These definitions and purposes are specific to this method but have
been conformed to common usage to the extent possible.
    23.1 Units of weight and measure and their abbreviations.
    23.1.1 Symbols

[deg]C degrees Celsius
[micro]g microgram
[mu]L microliter
< less than
<= less than or equal to
> greater than
% percent

23.1.2 Abbreviations (in alphabetical order)

cm centimeter
g gram

hr hour
ID inside diameter
in. inch
L liter
M molar solution--one mole or gram molecular weight of solute in one
liter of solution
mg milligram
min minute
mL milliliter
mm millimeter
N Normality--one equivalent of solute in one liter of solution
ng nanogram
psia pounds-per-square inch absolute
psig pounds-per-square inch gauge
v/v volume per unit volume
w/v weight per unit volume

    23.2 Definitions and acronyms (in alphabetical order)
    Analyte--A compound or mixture of compounds (e.g., PCBs) tested for
by this method. The analytes are listed in Tables 1 and 2.
    Analytical batch--The set of samples analyzed on a given instrument
during a 24-hour period that begins and ends with calibration
verification (Sections 7.8 and 13). See also ``Extraction batch.''
    Blank (method blank; laboratory blank)--An aliquot of reagent water
that is treated exactly as a sample including exposure to all
glassware, equipment, solvents, reagents, internal standards, and
surrogates that are used with samples. The blank is used to determine
if analytes or interferences are present in the laboratory environment,
the reagents, or the apparatus.
    Calibration factor (CF)--See Section 7.5.1.
    Calibration standard--A solution prepared from stock solutions and/
or a secondary standards and containing the analytes of interest,
surrogates, and internal standards. This standard is used to model the
response of the GC instrument against analyte concentration.
    Calibration verification--The process of confirming that the
response of the analytical system remains within specified limits of
the calibration.
    Calibration verification standard--The combined QC standard
(Section 7.7) used to verify calibration (Section 13.5) and for LCS
tests (Section 8.4).
    Extraction Batch--A set of up to 20 field samples (not including QC
samples) started through the extraction process in a given 24-hour
shift. Each extraction batch of 20 or fewer samples must be accompanied
by a blank (Section 8.5), a laboratory control sample (LCS, Section
8.4), a matrix spike and duplicate (MS/MSD; Section 8.3), resulting in
a minimum of five samples (1 field sample, 1 blank, 1 LCS, 1 MS, and 1
MSD) and a maximum of 24 samples (20 field samples, 1 blank, 1 LCS, 1
MS, and 1 MSD) for the batch. If greater than 20 samples are to be
extracted in a 24-hour shift, the samples must be separated into
extraction batches of 20 or fewer samples.
    Field Duplicates--Two samples collected at the same time and place
under identical conditions, and treated identically throughout field
and laboratory procedures. Results of analyses the field duplicates
provide an estimate of the precision associated with sample collection,
preservation, and storage, as well as with laboratory procedures.
    Field blank--An aliquot of reagent water or other reference matrix
that is placed in a sample container in the field, and treated as a
sample in all respects, including exposure to sampling site conditions,
storage, preservation, and all analytical procedures. The purpose of
the field blank is to determine if the field or sample transporting
procedures and environments have contaminated the sample. See also
``Blank.''
    GC--Gas chromatograph or gas chromatography
    Gel-permeation chromatography (GPC)--A form of liquid
chromatography in which the analytes are separated based on exclusion
from the solid phase by size.
    Internal standard--A compound added to an extract or standard
solution in a known amount and used as a reference for quantitation of
the analytes of interest and surrogates. Also see Internal standard
quantitation.
    Internal standard quantitation--A means of determining the
concentration of an analyte of interest (Tables 1 and 2) by reference
to a compound not expected to be found in a sample.
    IDC--Initial Demonstration of Capability (Section 8.2); four
aliquots of a reference matrix spiked with the analytes of interest and
analyzed to establish the ability of the laboratory to generate
acceptable precision and recovery. An IDC is performed prior to the
first time this method is used and any time the method or
instrumentation is modified.
    Laboratory Control Sample (LCS; laboratory fortified blank; Section
8.4)--An aliquot of reagent water spiked with known quantities of the
analytes of interest and surrogates. The LCS is analyzed exactly like a
sample. Its purpose is to assure that the results produced by the
laboratory remain within the limits specified in this method for
precision and recovery.
    Laboratory Fortified Sample Matrix--See Matrix spike.
    Laboratory reagent blank--See blank.
    Matrix spike (MS) and matrix spike duplicate (MSD) (laboratory
fortified sample matrix and duplicate)--Two aliquots of an
environmental sample to which known quantities of the analytes of
interest and surrogates are added in the laboratory. The MS/MSD are
prepared and analyzed exactly like a field sample. Their purpose is to
quantify any additional bias and imprecision caused by the sample
matrix. The background concentrations of the analytes in the sample
matrix must be determined in a separate aliquot and the measured values
in the MS/MSD corrected for background concentrations.
    May--This action, activity, or procedural step is neither required
nor prohibited.
    May not--This action, activity, or procedural step is prohibited.
    Method detection limit (MDL)--A detection limit determined by the
procedure at 40 CFR part 136, appendix B. The MDLs determined by EPA
are listed in Tables 1 and 2. As noted in Sec. 1.6, use the MDLs in
Tables 1 and 2 in conjunction with current MDL data from the laboratory
actually analyzing samples to assess the sensitivity of this procedure
relative to project objectives and regulatory requirements (where
applicable).
    Minimum level (ML)--The term ``minimum level'' refers to either the
sample concentration equivalent to the lowest calibration point in a
method or a multiple of the method detection limit (MDL), whichever is
higher. Minimum levels may be obtained in several ways: They may be
published in a method; they may be based on the lowest acceptable
calibration point used by a laboratory; or they may be calculated by
multiplying the MDL in a method, or the MDL determined by a laboratory,
by a factor of 3. For the purposes of NPDES compliance monitoring, EPA
considers the following terms to be synonymous: ``quantitation limit,''
``reporting limit,'' and ``minimum level.''
    MS--Mass spectrometer or mass spectrometry.
    Must--This action, activity, or procedural step is required.
    Preparation blank--See blank.
    Quality control sample (QCS)--A sample containing analytes of
interest at known concentrations. The QCS is obtained from a source
external to the laboratory or is prepared from standards obtained from
a different source than the calibration standards. The purpose is to
check laboratory performance using test materials that have been
prepared independent of the normal preparation process.

    Reagent water--Water demonstrated to be free from the analytes of
interest and potentially interfering substances at the MDLs for the
analytes in this method.
    Regulatory compliance limit--A limit on the concentration or amount
of a pollutant or contaminant specified in a nationwide standard, in a
permit, or otherwise established by a regulatory/control authority.
    Relative standard deviation (RSD)--The standard deviation times 100
divided by the mean. Also termed ``coefficient of variation.''
    RF--Response factor. See Section 7.6.2.
    RPD--Relative percent difference.
    RSD--See relative standard deviation.
    Safety Data Sheet (SDS)--Written information on a chemical's
toxicity, health hazards, physical properties, fire, and reactivity,
including storage, spill, and handling precautions that meet the
requirements of OSHA, 29 CFR 1910.1200(g) and appendix D to Sec.
1910.1200. United Nations Globally Harmonized System of Classification
and Labelling of Chemicals (GHS), third revised edition, United
Nations, 2009.
    Should--This action, activity, or procedural step is suggested but
not required.
    SPE--Solid-phase extraction; a sample extraction or extract cleanup
technique in which an analyte is selectively removed from a sample or
extract by passage over or through a material capable of reversibly
adsorbing the analyte.
    Stock solution--A solution containing an analyte that is prepared
using a reference material traceable to EPA, the National Institute of
Science and Technology (NIST), or a source that will attest to the
purity and authenticity of the reference material.
    Surrogate--A compound unlikely to be found in a sample, which is
spiked into the sample in a known amount before extraction, and which
is quantified with the same procedures used to quantify other sample
components. The purpose of the surrogate is to monitor method
performance with each sample.
* * * * *

Method 611--Haloethers

1. Scope and Application
    1.1 This method covers the determination of certain haloethers. The
following parameters can be determined by this method:

------------------------------------------------------------------------
                Parameter                   STORET No.        CAS No.
------------------------------------------------------------------------
Bis(2-chloroethyl) ether................           34273        111-44-4
Bis(2-chloroethoxy) methane.............           34278        111-91-1
2, 2'-oxybis (1-chloropropane)..........           34283        108-60-1
4-Bromophenyl phenyl ether..............           34636        101-55-3
4-Chlorophenyl phenyl either............           34641       7005-72-3
------------------------------------------------------------------------

* * * * *

Method 624.1--Purgeables by GC/MS

1. Scope and Application
    1.1 This method is for determination of purgeable organic
pollutants in industrial discharges and other environmental samples by
gas chromatography combined with mass spectrometry (GC/MS), as provided
under 40 CFR 136.1. This revision is based on previous protocols
(References 1-3), on the revision promulgated October 26, 1984 (49 FR
43234), and on an interlaboratory method validation study (Reference
4). Although this method was validated through an interlaboratory study
conducted more than 29 years ago, the fundamental chemistry principles
used in this method remain sound and continue to apply.
    1.2 The analytes that may be qualitatively and quantitatively
determined using this method and their CAS Registry numbers are listed
in Table 1. The method may be extended to determine the analytes listed
in Table 2; however, poor purging efficiency or gas chromatography of
some of these analytes may make quantitative determination difficult.
For example, an elevated temperature may be required to purge some
analytes from water. If an elevated temperature is used, calibration
and all quality control (QC) tests must be performed at the elevated
temperature. EPA encourages the use of this method to determine
additional compounds amenable to purge-and-trap GC/MS.
    1.3 The large number of analytes in Tables 1 and 2 of this method
makes testing difficult if all analytes are determined simultaneously.
Therefore, it is necessary to determine and perform QC tests for
``analytes of interest'' only. Analytes of interest are those required
to be determined by a regulatory/control authority or in a permit, or
by a client. If a list of analytes is not specified, the analytes in
Table 1 must be determined, at a minimum, and QC testing must be
performed for these analytes. The analytes in Table 1 and some of the
analytes in Table 2 have been identified as Toxic Pollutants (40 CFR
401.15), expanded to a list of Priority Pollutants (40 CFR part 423,
appendix A).
    1.4 Method detection limits (MDLs; Reference 5) for the analytes in
Table 1 are listed in that table. These MDLs were determined in reagent
water (Reference 6). Advances in analytical technology, particularly
the use of capillary (open-tubular) columns, allowed laboratories to
routinely achieve MDLs for the analytes in this method that are 2-10
times lower than those in the version promulgated in 1984 (40 FR
43234). The MDL for a specific wastewater may differ from those listed,
depending on the nature of interferences in the sample matrix.
    1.4.1 EPA has promulgated this method at 40 CFR part 136 for use in
wastewater compliance monitoring under the National Pollutant Discharge
Elimination System (NPDES). The data reporting practices described in
Section 13.2 are focused on such monitoring needs and may not be
relevant to other uses of the method.
    1.4.2 This method includes ``reporting limits'' based on EPA's
``minimum level'' (ML) concept (see the glossary in Section 20). Table
1 contains MDL values and ML values for many of the analytes. The MDL
for an analyte in a specific wastewater may differ from that listed in
Table 1, depending upon the nature of interferences in the sample
matrix.
    1.5 This method is performance-based. It may be modified to improve
performance (e.g., to overcome interferences or improve the accuracy of
results) provided all performance requirements are met.
    1.5.1 Examples of allowed method modifications are described at 40
CFR 136.6. Other examples of allowed modifications specific to this
method are described in Section 8.1.2.
    1.5.2 Any modification beyond those expressly allowed at 40 CFR
136.6 or in Section 8.1.2 of this method shall be considered a major
modification that is subject to application and approval of an
alternate test procedure under 40 CFR 136.4 and 136.5.

    1.5.3 For regulatory compliance, any modification must be
demonstrated to produce results equivalent or superior to results
produced by this method when applied to relevant wastewaters (Section
8.3).
    1.6 This method is restricted to use by or under the supervision of
analysts experienced in the operation of a purge-and-trap system and a
gas chromatograph/mass spectrometer and in the interpretation of mass
spectra. Each analyst must demonstrate the ability to generate
acceptable results with this method using the procedure in Section 8.2.
    1.7 Terms and units of measure used in this method are given in the
glossary at the end of the method.
2. Summary of Method
    2.1 A gas is bubbled through a measured volume of water in a
specially-designed purging chamber (Figure 1). The purgeables are
efficiently transferred from the aqueous phase to the vapor phase. The
vapor is swept through a sorbent trap where the purgeables are trapped
(Figure 2). After purging is completed, the trap is heated and
backflushed with the gas to desorb the purgeables onto a gas
chromatographic column (Figures 3 and 4). The column is temperature
programmed to separate the purgeables which are then detected with a
mass spectrometer.
    2.2 Different sample sizes in the range of 5-25 mL are allowed in
order to meet differing sensitivity requirements. Calibration and QC
samples must have the same volume as field samples.
3. Interferences
    3.1 Impurities in the purge gas, organic compounds outgassing from
the plumbing ahead of the trap, and solvent vapors in the laboratory
account for the majority of contamination problems. The analytical
system must be demonstrated to be free from contamination under the
conditions of the analysis by analyzing blanks as described in Section
8.5. Fluoropolymer tubing, fittings, and thread sealant should be used
to avoid contamination.
    3.2 Samples can be contaminated by diffusion of volatile organics
(particularly fluorocarbons and methylene chloride) through the septum
seal into the sample during shipment and storage. Protect samples from
sources of volatiles during collection, shipment, and storage. A
reagent water field blank carried through sampling and analysis can
serve as a check on such contamination.
    3.3 Contamination by carry-over can occur whenever high level and
low level samples are analyzed sequentially. To reduce the potential
for carry-over, the purging device and sample syringe must be rinsed
with reagent water between sample analyses. Whenever an unusually
concentrated sample is encountered, it should be followed by an
analysis of a blank to check for cross contamination. For samples
containing large amounts of water-soluble materials, suspended solids,
high boiling compounds or high purgeable levels, it may be necessary to
wash the purging device with a detergent solution, rinse it with
distilled water, and then dry it in a 105 [deg]C oven between analyses.
The trap and other parts of the system are also subject to
contamination; therefore, frequent bakeout and purging of the entire
system may be required. Screening samples at high dilution may prevent
introduction of contaminants into the system.
4. Safety
    4.1 The toxicity or carcinogenicity of each reagent used in this
method has not been precisely defined; however, each chemical compound
should be treated as a potential health hazard. From this viewpoint,
exposure to these chemicals must be reduced to the lowest possible
level. The laboratory is responsible for maintaining a current
awareness file of OSHA regulations regarding the safe handling of the
chemicals specified in this method. A reference file of safety data
sheets (SDSs, OSHA, 29 CFR 1910.1200(g)) should also be made available
to all personnel involved in sample handling and chemical analysis.
Additional references to laboratory safety are available and have been
identified (References 7-9) for the information of the analyst.
    4.2. The following analytes covered by this method have been
tentatively classified as known or suspected human or mammalian
carcinogens: Benzene; carbon tetrachloride; chloroform; 1,4-
dichlorobenzene; 1,2-dichloroethane; 1,2-dichloropropane; methylene
chloride; tetrachloroethylene; trichloroethylene; and vinyl chloride.
Primary standards of these toxic compounds should be prepared in a
chemical fume hood, and a NIOSH/MESA approved toxic gas respirator
should be worn when handling high concentrations of these compounds.
    4.3 This method allows the use of hydrogen as a carrier gas in
place of helium (Section <IP_ADDRESS>). The laboratory should take the
necessary precautions in dealing with hydrogen, and should limit
hydrogen flow at the source to prevent buildup of an explosive mixture
of hydrogen in air.
5. Apparatus and Materials

    Note:  Brand names, suppliers, and part numbers are cited for
illustration purposes only. No endorsement is implied. Equivalent
performance may be achieved using equipment and materials other than
those specified here. Demonstration of equivalent performance that
meets the requirements of this method is the responsibility of the
laboratory. Suppliers for equipment and materials in this method may
be found through an on-line search.

    5.1 Sampling equipment for discrete sampling.
    5.1.1 Vial--25 or 40 mL capacity, or larger, with screw cap with a
hole in the center (Pierce #13075 or equivalent). Unless pre-cleaned,
detergent wash, rinse with tap and reagent water, and dry at 105 [deg]C
before use.
    5.1.2 Septum--Fluoropolymer-faced silicone (Pierce #12722 or
equivalent). Unless pre-cleaned, detergent wash, rinse with tap and
reagent water, and dry at 105  5 [deg]C for one hour before
use.
    5.2 Purge-and-trap system--The purge-and-trap system consists of
three separate pieces of equipment: A purging device, trap, and
desorber. Several complete systems are commercially available. Any
system that meets the performance requirements in this method may be
used.
    5.2.1 The purging device should accept 5- to 25-mL samples with a
water column at least 3 cm deep. The purge gas must pass though the
water column as finely divided bubbles. The purge gas must be
introduced no more than 5 mm from the base of the water column. The
purging device illustrated in Figure 1 meets these design criteria.
Purge devices of a different volume may be used so long as the
performance requirements in this method are met.
    5.2.2 The trap should be at least 25 cm long and have an inside
diameter of at least 0.105 in. The trap should be packed to contain the
following minimum lengths of adsorbents: 1.0 cm of methyl silicone
coated packing (Section 6.3.2), 15 cm of 2,6-diphenylene oxide polymer
(Section 6.3.1), and 8 cm of silica gel (Section 6.3.3). The minimum
specifications for the trap are illustrated in Figure 2. A trap with
different dimensions and packing materials is acceptable so long as the
performance requirements in this method are met.
    5.2.3 The desorber should be capable of rapidly heating the trap to
the temperature necessary to desorb the analytes of interest, and of
maintaining

this temperature during desorption. The trap should not be heated
higher than the maximum temperature recommended by the manufacturer.
The desorber illustrated in Figure 2 meets these design criteria.
    5.2.4 The purge-and-trap system may be assembled as a separate unit
or coupled to a gas chromatograph as illustrated in Figures 3 and 4.
    5.3 GC/MS system.
    5.3.1 Gas chromatograph (GC)--An analytical system complete with a
temperature programmable gas chromatograph and all required
accessories, including syringes and analytical columns. Autosamplers
designed for purge-and-trap analysis of volatiles also may be used.
    <IP_ADDRESS> Injection port--Volatiles interface, split, splitless,
temperature programmable split/splitless (PTV), large volume, on-
column, backflushed, or other.
    <IP_ADDRESS> Carrier gas--Data in the tables in this method were
obtained using helium carrier gas. If another carrier gas is used,
analytical conditions may need to be adjusted for optimum performance,
and calibration and all QC tests must be performed with the alternate
carrier gas. See Section 4.3 for precautions regarding the use of
hydrogen as a carrier gas.
    5.3.2 GC column--See the footnote to Table 3. Other columns or
column systems may be used provided all requirements in this method are
met.
    5.3.3 Mass spectrometer--Capable of repetitively scanning from 35-
260 Daltons (amu) every 2 seconds or less, utilizing a 70 eV (nominal)
electron energy in the electron impact ionization mode, and producing a
mass spectrum which meets all criteria in Table 4 when 50 ng or less of
4-bromofluorobenzene (BFB) is injected through the GC inlet. If
acrolein, acrylonitrile, chloromethane, and vinyl chloride are to be
determined, it may be necessary to scan from below 25 Daltons to
measure the peaks in the 26--35 Dalton range for reliable
identification.
    5.3.4 GC/MS interface--Any GC to MS interface that meets all
performance requirements in this method may be used.
    5.3.5 Data system--A computer system must be interfaced to the mass
spectrometer that allows continuous acquisition and storage of mass
spectra throughout the chromatographic program. The computer must have
software that allows searching any GC/MS data file for specific m/z's
(masses) and plotting m/z abundances versus time or scan number. This
type of plot is defined as an extracted ion current profile (EICP).
Software must also be available that allows integrating the abundance
at any EICP between specified time or scan number limits.
    5.4 Syringes--Graduated, 5-25 mL, glass hypodermic with Luerlok
tip, compatible with the purging device.
    5.5 Micro syringes--Graduated, 25-1000 [mu]L, with 0.006 in. ID
needle.
    5.6 Syringe valve--Two-way, with Luer ends.
    5.7 Syringe--5 mL, gas-tight with shut-off valve.
    5.8 Bottle--15 mL, screw-cap, with Teflon cap liner.
    5.9 Balance--Analytical, capable of accurately weighing 0.0001 g.
    6. Reagents
    6.1 Reagent water--Reagent water is defined as water in which the
analytes of interest and interfering compounds are not detected at the
MDLs of the analytes of interest. It may be generated by passing
deionized water, distilled water, or tap water through a carbon bed,
passing the water through a water purifier, or heating the water to
between 90 and 100 [deg]C while bubbling contaminant free gas through
it for approximately 1 hour. While still hot, transfer the water to
screw-cap bottles and seal with a fluoropolymer-lined cap.
    6.2 Sodium thiosulfate--(ACS) Granular.
    6.3 Trap materials.
    6.3.1 2,6-Diphenylene oxide polymer--Tenax, 60/80 mesh,
chromatographic grade, or equivalent.
    6.3.2 Methyl silicone packing--3% OV-1 on Chromosorb-W, 60/80 mesh,
or equivalent.
    6.3.3 Silica gel--35/60 mesh, Davison, Grade-15 or equivalent.
    Other trap materials are acceptable if performance requirements in
this method are met.
    6.4 Methanol--Demonstrated to be free from the target analytes and
potentially interfering compounds.
    6.5 Stock standard solutions--Stock standard solutions may be
prepared from pure materials, or purchased as certified solutions.
Traceability must be to the National Institute of Standards and
Technology (NIST) or other national standard. Stock solution
concentrations alternate to those below may be used. Prepare stock
standard solutions in methanol using assayed liquids or gases as
appropriate. Because some of the compounds in this method are known to
be toxic, primary dilutions should be prepared in a hood, and a NIOSH/
MESA approved toxic gas respirator should be worn when high
concentrations of neat materials are handled. The following procedure
may be used to prepare standards from neat materials:
    6.5.1 Place about 9.8 mL of methanol in a 10-mL ground-glass-
stoppered volumetric flask. Allow the flask to stand, unstoppered, for
about 10 minutes or until all alcohol wetted surfaces have dried. Weigh
the flask to the nearest 0.1 mg.
    6.5.2 Add the assayed reference material.
    <IP_ADDRESS> Liquids--Using a 100 [mu]L syringe, immediately add two or
more drops of assayed reference material to the flask. Be sure that the
drops fall directly into the alcohol without contacting the neck of the
flask. Reweigh, dilute to volume, stopper, then mix by inverting the
flask several times. Calculate the concentration in [mu]g/[mu]L from
the net gain in weight.
    <IP_ADDRESS> Gases--To prepare standards for any of compounds that boil
below 30 [deg]C, fill a 5-mL valved gas-tight syringe with reference
standard vapor to the 5.0 mL mark. Lower the needle to 5 mm above the
methanol meniscus. Slowly introduce the vapor above the surface of the
liquid (the vapor will rapidly dissolve in the methanol). Reweigh,
dilute to volume, stopper, then mix by inverting the flask several
times. Calculate the concentration in [mu]g/[mu]L from the net gain in
weight.
    6.5.3 When compound purity is assayed to be 96% or greater, the
weight may be used without correction to calculate the concentration of
the stock standard. Commercially prepared stock standards may be used
at any concentration if they are certified by the manufacturer or by an
independent source.
    6.5.4 Prepare fresh standards weekly for the gases and 2-
chloroethylvinyl ether. All standards should be replaced after one
month, or sooner if the concentration of an analyte changes by more
than 10 percent.

    Note:  2-Chloroethylvinyl ether has been shown to be stable for
as long as one month if prepared as a separate standard, and the
other analytes have been shown to be stable for as long as 2 months
if stored at less than -10 [deg]C with minimal headspace in sealed,
miniature inert-valved vials.

    6.6 Secondary dilution standards--Using stock solutions, prepare
secondary dilution standards in methanol that contain the compounds of
interest, either singly or mixed. Secondary dilution standards should
be prepared at concentrations such that the aqueous calibration
standards prepared in Section 7.3.2 will bracket the working range of
the analytical system.
    6.7 Surrogate standard spiking solution--Select a minimum of three
surrogate compounds from Table 5. The surrogates selected should match
the purging characteristics of the analytes of interest as closely as
possible. Prepare a stock standard solution for each

surrogate in methanol as described in Section 6.5, and prepare a
solution for spiking the surrogates into all blanks, LCSs, and MS/MSDs.
The spiking solution should be prepared such that spiking a small
volume will result in surrogate concentrations near the mid-point of
the calibration range. For example, adding 10 [mu]L of a spiking
solution containing the surrogates at a concentration of 15 [mu]g/mL in
methanol to a 5-mL aliquot of water would result in a concentration of
30 [mu]g/L for each surrogate. Other surrogate concentrations may be
used.
    6.8 BFB standard--Prepare a solution of BFB in methanol as
described in Sections 6.5 and 6.6. The solution should be prepared such
that an injection or purging from water will result in introduction of
<=50 ng into the GC. BFB may be included in a mixture with the internal
standards and/or surrogates.
    6.9 Quality control check sample concentrate--See Section 8.2.1.
    6.10 Storage--When not being used, store standard solutions
(Sections 6.5-6.9) at -10 to -20 [deg]C, protected from light, in
fluoropolymer-sealed glass containers with minimal headspace.
7. Calibration
    7.1 Assemble a purge-and-trap system that meets the specifications
in Section 5.2. Prior to first use, condition the trap overnight at 180
[deg]C by backflushing with gas at a flow rate of at least 20 mL/min.
Condition the trap daily prior to use.
    7.2 Connect the purge-and-trap system to the gas chromatograph. The
gas chromatograph should be operated using temperature and flow rate
conditions equivalent to those given in the footnotes to Table 3.
Alternative temperature and flow rate conditions may be used provided
that performance requirements in this method are met.
    7.3 Internal standard calibration.
    7.3.1 Internal standards.
    <IP_ADDRESS> Select three or more internal standards similar in
chromatographic behavior to the compounds of interest. Suggested
internal standards are listed in Table 5. Use the base peak m/z as the
primary m/z for quantification of the standards. If interferences are
found at the base peak, use one of the next two most intense m/z's for
quantitation. Demonstrate that measurement of the internal standards
are not affected by method or matrix interferences.
    <IP_ADDRESS> To assure accurate analyte identification, particularly
when selected ion monitoring (SIM) is used, it may be advantageous to
include more internal standards than those suggested in Section
<IP_ADDRESS>. An analyte will be located most accurately if its retention
time relative to an internal standard is in the range of 0.8 to 1.2.
    <IP_ADDRESS> Prepare a stock standard solution for each internal
standard surrogate in methanol as described in Section 6.5, and prepare
a solution for spiking the internal standards into all blanks, LCSs,
and MS/MSDs. The spiking solution should be prepared such that spiking
a small volume will result in internal standard concentrations near the
mid-point of the calibration range. For example, adding 10 [mu]L of a
spiking solution containing the internal standards at a concentration
of 15 [mu]g/mL in methanol to a 5-mL aliquot of water would result in a
concentration of 30 [mu]g/L for each internal standard. Other
concentrations may be used. The internal standard solution and the
surrogate standard spiking solution (Section 6.7) may be combined, if
desired. Store the solution at <6 [deg]C in fluoropolymer-sealed glass
containers with a minimum of headspace. Replace the solution after 1
month, or more frequently if comparison with QC standards indicates a
problem.
    7.3.2 Calibration.
    <IP_ADDRESS> Calibration standards.
    <IP_ADDRESS>.1 Prepare calibration standards at a minimum of five
concentration levels for each analyte of interest by adding appropriate
volumes of one or more stock standards to a fixed volume (e.g., 40 mL)
of reagent water in volumetric glassware. Fewer levels may be necessary
for some analytes based on the sensitivity of the MS. The concentration
of the lowest calibration standard for an analyte should be at or near
the ML value in Table 1 for an analyte listed in that table. The ML
value may be rounded to a whole number that is more convenient for
preparing the standard, but must not exceed the ML values listed in
Table 1 for those analytes which list ML values. Alternatively, the
laboratory may establish the ML for each analyte based on the
concentration of the lowest calibration standard in a series of
standards obtained from a commercial vendor, again, provided that the
ML values does not exceed the MLs in Table 1, and provided that the
resulting calibration meets the acceptance criteria in Section 7.3.4,
based on the RSD, RSE, or R\2\.
    The concentrations of the higher standards should correspond to the
expected range of concentrations found in real samples, or should
define the working range of the GC/MS system for full-scan and/or SIM
operation, as appropriate. A minimum of six concentration levels is
required for a second order, non-linear (e.g., quadratic; ax\2\ + bx +
c) calibration. Calibrations higher than second order are not allowed.
    <IP_ADDRESS>.2 To each calibration standard or standard mixture, add a
known constant volume of the internal standard spiking solution
(Section <IP_ADDRESS>) and surrogate standard spiking solution (Section 6.7)
or the combined internal standard solution and surrogate spiking
solution (Section <IP_ADDRESS>). Aqueous standards may be stored up to 24
hours, if held in sealed vials with zero headspace as described in
Section 9.1. If not so stored, they must be discarded after one hour.
    <IP_ADDRESS> Prior to analysis of the calibration standards, analyze the
BFB standard (Section 6.8) and adjust the scan rate of the MS to
produce a minimum of 5 mass spectra across the BFB GC peak, but do not
exceed 2 seconds per scan. Adjust instrument conditions until the BFB
criteria in Table 4 are met.

    Note: The BFB spectrum may be evaluated by summing the
intensities of the m/z's across the GC peak, subtracting the
background at each m/z in a region of the chromatogram within 20
scans of but not including any part of the BFB peak. The BFB
spectrum may also be evaluated by fitting a Gaussian to each m/z and
using the intensity at the maximum for each Gaussian, or by
integrating the area at each m/z and using the integrated areas.
Other means may be used for evaluation of the BFB spectrum so long
as the spectrum is not distorted to meet the criteria in Table 4.

    <IP_ADDRESS> Analyze the mid-point standard and enter or review the
retention time, relative retention time, mass spectrum, and
quantitation m/z in the data system for each analyte of interest,
surrogate, and internal standard. If additional analytes (Table 2) are
to be quantified, include these analytes in the standard. The mass
spectrum for each analyte must be comprised of a minimum of 2 m/z's; 3
to 5 m/z's assure more reliable analyte identification. Suggested
quantitation m/z's are shown in Table 6 as the primary m/z. For
analytes in Table 6 that do not have a secondary m/z, acquire a mass
spectrum and enter one or more secondary m/z's for more reliable
identification. If an interference occurs at the primary m/z, use one
of the secondary m/z's or an alternate m/z. A single m/z only is
required for quantitation.
    <IP_ADDRESS> For SIM operation, determine the analytes in each
descriptor, the quantitation m/z for each analyte (the quantitation m/z
can be the same as for full-scan operation; Section <IP_ADDRESS>), the dwell
time on each m/z for each analyte,

and the beginning and ending retention time for each descriptor.
Analyze the verification standard in scan mode to verify m/z's and
establish retention times for the analytes. There must be a minimum of
two m/z's for each analyte to assure analyte identification. To
maintain sensitivity, the number of m/z's in a descriptor should be
limited. For example, for a descriptor with 10 m/z's and a
chromatographic peak width of 5 sec, a dwell time of 100 ms at each m/z
would result in a scan time of 1 second and provide 5 scans across the
GC peak. The quantitation m/z will usually be the most intense peak in
the mass spectrum. The quantitation m/z and dwell time may be optimized
for each analyte. However, if a GC peak spans two (or more)
descriptors, the dwell time and cycle time (scans/sec) should be set to
the same value in both segments in order to maintain equivalent
response. The acquisition table used for SIM must take into account the
mass defect (usually less than 0.2 Dalton) that can occur at each m/z
monitored.
    <IP_ADDRESS> For combined scan and SIM operation, set up the scan
segments and descriptors to meet requirements in Sections <IP_ADDRESS>-
<IP_ADDRESS>.
    7.3.3 Analyze each calibration standard according to Section 10 and
tabulate the area at the quantitation m/z against concentration for
each analyte of interest, surrogate, and internal standard. Calculate
the response factor (RF) for each compound at each concentration using
Equation 1.
[GRAPHIC] [TIFF OMITTED] TP19FE15.012

Where:

As = Area of the characteristic m/z for the analyte to be
measured.
Ais = Area of the characteristic m/z for the internal
standard.
Cis = Concentration of the internal standard ([mu]g/L).
Cs = Concentration of the analyte to be measured ([mu]g/
L).

    7.3.4 Calculate the mean (average) and relative standard deviation
(RSD) of the response factors. If the RSD is less than 35%, the RF can
be assumed to be invariant and the average RF can be used for
calculations. Alternatively, the results can be used to fit a linear or
quadratic regression of response ratios, As/Ais,
vs. concentration ratios Cs/Cis. If used, the regression must be
weighted inversely proportional to concentration (1/C). The coefficient
of determination (R\2\) of the weighted regression must be greater than
0.920 (this value roughly corresponds to the RSD limit of 35%).
Alternatively, the relative standard error (Reference 10) may be used
as an acceptance criterion. As with the RSD, the RSE must be less than
35%. If an RSE less than 35% cannot be achieved for a quadratic
regression, system performance is unacceptable, and the system must be
adjusted and re-calibrated.

    Note:  Using capillary columns and current instrumentation, it
is quite likely that a laboratory can calibrate the target analytes
in this method and achieve a linearity metric (either RSD or RSE)
well below 35%. Therefore, laboratories are permitted to use more
stringent acceptance criteria for calibration than described here,
for example, to harmonize their application of this method with
those from other sources.

    7.4 Calibration verification--Because the analytical system is
calibrated by purge of the analytes from water, calibration
verification is performed using the laboratory control sample (LCS).
See Section 8.4 for requirements for calibration verification using the
LCS, and the Glossary for further definition.
8. Quality Control
    8.1 Each laboratory that uses this method is required to operate a
formal quality assurance program. The minimum requirements of this
program consist of an initial demonstration of laboratory capability
and ongoing analysis of spiked samples and blanks to evaluate and
document data quality (40 CFR 136.7). The laboratory must maintain
records to document the quality of data generated. Results of ongoing
performance tests are compared with established QC acceptance criteria
to determine if the results of analyses meet performance requirements
of this method. When results of spiked samples do not meet the QC
acceptance criteria in this method, a quality control check sample
(laboratory control sample; LCS) must be analyzed to confirm that the
measurements were performed in an in-control mode of operation. A
laboratory may develop its own performance criteria (as QC acceptance
criteria), provided such criteria are as or more restrictive than the
criteria in this method.
    8.1.1 The laboratory must make an initial demonstration of
capability (DOC) to generate acceptable precision and recovery with
this method. This demonstration is detailed in Section 8.2.
    8.1.2 In recognition of advances that are occurring in analytical
technology, and to overcome matrix interferences, the laboratory is
permitted certain options (Section 1.5 and 40 CFR 136.6(b)) to improve
separations or lower the costs of measurements. These options may
include an alternate purge-and-trap device, and changes in both column
and type of mass spectrometer (see 40 CFR 136.6(b)(4)(xvi)). Alternate
determinative techniques, such as substitution of spectroscopic or
immunoassay techniques, and changes that degrade method performance,
are not allowed. If an analytical technique other than GC/MS is used,
that technique must have a specificity equal to or greater than the
specificity of GC/MS for the analytes of interest. The laboratory is
also encouraged to participate in inter-comparison and performance
evaluation studies (see Section 8.9).
    <IP_ADDRESS> Each time a modification is made to this method, the
laboratory is required to repeat the procedure in Section 8.2. If the
detection limit of the method will be affected by the change, the
laboratory must demonstrate that the MDLs (40 CFR part 136, appendix B)
are lower than one-third the regulatory compliance limit, or at least
as low as the MDLs listed in this method, whichever are greater. If
calibration will be affected by the change, the instrument must be
recalibrated per Section 7. Once the modification is demonstrated to
produce results equivalent or superior to results produced by this
method, that modification may be used routinely thereafter, so long as
the other requirements in this method are met (e.g., matrix spike/
matrix spike duplicate recovery and relative percent difference).
    <IP_ADDRESS>.1 If a modification is to be applied to a specific
discharge, the laboratory must prepare and analyze matrix spike/matrix
spike duplicate (MS/MSD) samples (Section 8.3) and LCS samples (Section
8.4). The laboratory must include internal standards and surrogates
(Section 8.7) in each of the samples. The MS/MSD and LCS samples must
be fortified with the analytes of interest (Section 1.3.). If the
modification is for nationwide use, MS/

MSD samples must be prepared from a minimum of nine different
discharges (See Section <IP_ADDRESS>.2), and all QC acceptance criteria in
this method must be met. This evaluation only needs to be performed
once, other than for the routine QC required by this method (for
example it could be performed by the vendor of the alternate materials)
but any laboratory using that specific material must have the results
of the study available. This includes a full data package with the raw
data that will allow an independent reviewer to verify each
determination and calculation performed by the laboratory (see Section
<IP_ADDRESS>.5, items a-l).
    <IP_ADDRESS>.2 Sample matrices on which MS/MSD tests must be performed
for nationwide use of an allowed modification:
    (a) Effluent from a POTW
    (b) ASTM D5905 Standard Specification for Substitute Wastewater
    (c) Sewage sludge, if sewage sludge will be in the permit
    (d) ASTM D1141 Standard Specification for Substitute Ocean Water,
if ocean water will be in the permit
    (e) Untreated and treated wastewaters up to a total of nine matrix
types (see http:water.epa.gov/scitech/wastetech/guide/industry.cfm) for
a list of industrial categories with existing effluent guidelines).
    At least one of the above wastewater matrix types must have at
least one of the following characteristics:
    (i) Total suspended solids greater than 40 mg/L
    (ii) Total dissolved solids greater than 100 mg/L
    (iii) Oil and grease greater than 20 mg/L
    (iv) NaCl greater than 120 mg/L
    (v) CaCO3 greater than 140 mg/L
    The interim acceptance criteria for MS, MSD recoveries that do not
have recovery limits specified in Table 7, and recoveries for
surrogates that do not have recovery limits specified in Table 7, must
be no wider than 60-140%, and the relative percent difference (RPD) of
the concentrations in the MS and MSD that do not have RPD limits
specified in Table 7 must be less than 30%. Alternatively, the
laboratory may use the laboratory's in-house limits if they are
tighter.
    (f) A proficiency testing (PT) sample from a recognized provider,
in addition to tests of the nine matrices (Section <IP_ADDRESS>.1).
    <IP_ADDRESS> The laboratory is required to maintain records of
modifications made to this method. These records include the following,
at a minimum:
    <IP_ADDRESS>.1 The names, titles, street addresses, telephone numbers,
and email addresses of the analyst(s) that performed the analyses and
modification, and of the quality control officer that witnessed and
will verify the analyses and modifications.
    <IP_ADDRESS>.2 A list of analytes, by name and CAS Registry Number.
    <IP_ADDRESS>.3 A narrative stating reason(s) for the modifications.
    <IP_ADDRESS>.4 Results from all quality control (QC) tests comparing the
modified method to this method, including:
    (a) Calibration (Section 7).
    (b) Calibration verification/LCS (Section 8.4).
    (c) Initial demonstration of capability (Section 8.2).
    (d) Analysis of blanks (Section 8.5).
    (e) Matrix spike/matrix spike duplicate analysis (Section 8.3).
    (f) Laboratory control sample analysis (Section 8.4).
    <IP_ADDRESS>.5 Data that will allow an independent reviewer to validate
each determination by tracing the instrument output (peak height, area,
or other signal) to the final result. These data are to include:
    (a) Sample numbers and other identifiers.
    (b) Analysis dates and times.
    (c) Analysis sequence/run chronology.
    (d) Sample volume (Section 10).
    (e) Sample dilution (Section 13.2).
    (f) Instrument and operating conditions.
    (g) Column (dimensions, material, etc).
    (h) Operating conditions (temperature program, flow rate, etc).
    (i) Detector (type, operating conditions, etc).
    (j) Chromatograms, mass spectra, and other recordings of raw data.
    (k) Quantitation reports, data system outputs, and other data to
link the raw data to the results reported.
    (l) A written Standard Operating Procedure (SOP).
    <IP_ADDRESS>.6 The individual laboratory wishing to use a given
modification must perform the start-up tests in Section 8.1.2 (e.g.,
DOC, MDL), with the modification as an integral part of this method
prior to applying the modification to specific discharges. Results of
the DOC must meet the QC acceptance criteria in Table 7 for the
analytes of interest (Section 1.3), and the MDLs must be equal to or
lower than the MDLs in Table3 for the analytes of interest
    8.1.3 Before analyzing samples, the laboratory must analyze a blank
to demonstrate that interferences from the analytical system, labware,
and reagents are under control. Each time a batch of samples is
analyzed or reagents are changed, a blank must be analyzed as a
safeguard against laboratory contamination. Requirements for the blank
are given in Section 8.5.
    8.1.4 The laboratory must, on an ongoing basis, spike and analyze a
minimum of one sample, in duplicate, with the batch of samples run
during a given 12-hour shift (see the note at Section 8.4). The
laboratory must also spike and analyze, in duplicate, a minimum of 5%
of all samples from a given site or discharge to monitor and evaluate
method and laboratory performance on the sample matrix. The batch and
site/discharge samples may be the same. The procedure for spiking and
analysis is given in Section 8.3.
    8.1.5 The laboratory must, on an ongoing basis, demonstrate through
analysis of a quality control check sample (laboratory control sample,
LCS; on-going precision and recovery sample, OPR) that the measurement
system is in control. This procedure is given in Section 8.4.
    8.1.6 The laboratory should maintain performance records to
document the quality of data that is generated. This procedure is given
in Section 8.8.
    8.1.7 The large number of analytes tested in performance tests in
this method present a substantial probability that one or more will
fail acceptance criteria when many analytes are tested simultaneously,
and a re-test is allowed if this situation should occur. If, however,
continued re-testing results in further repeated failures, the
laboratory should document the failures (e.g., as qualifiers on
results) and either avoid reporting results for analytes that failed or
report the problem and failures with the data. Failure to report does
not relieve a discharger or permittee of reporting timely results.
Results for regulatory compliance must be accompanied by QC results
that meet all acceptance criteria.
    8.2 Initial demonstration of capability (DOC)--To establish the
ability to generate acceptable recovery and precision, the laboratory
must perform the DOC in Sections 8.2.1 through 8.2.6 for the analytes
of interest. The laboratory must also establish MDLs for the analytes
of interest using the MDL procedure at 40 CFR part 136, appendix B. The
laboratory's MDLs must be equal to or lower than those listed in Table
1 for those analytes which list MDL values, or lower than one-third the
regulatory compliance limit, whichever is greater. For MDLs not listed
in Table 1, the laboratory must determine the MDLs using the MDL
procedure at 40 CFR part 136, appendix B under the same conditions

used to determine the MDLs for the analytes listed in Table 1. All
procedures used in the analysis must be included in the DOC.
    8.2.1 For the DOC, a QC check sample concentrate containing each
analyte of interest (Section 1.3) is prepared in methanol. The QC check
sample concentrate must be prepared independently from those used for
calibration, but may be from the same source as the second-source
standard used for calibration verification/LCS (Sections 7.4 and 8.4).
The concentrate should produce concentrations of the analytes of
interest in water at the mid-point of the calibration range, and may be
at the same concentration as the LCS (Section 8.4).

    Note:  QC check sample concentrates are no longer available from
EPA.

    8.2.2 Using a pipet or micro-syringe, prepare four LCSs by adding
an appropriate volume of the concentrate to each of four aliquots of
reagent water. The volume of reagent water must be the same as the
volume that will be used for the sample, blank (Section 8.5), and MS/
MSD (Section 8.3). A volume of 5 mL and a concentration of 20 [mu]g/L
were used to develop the QC acceptance criteria in Table 7. An
alternative volume and sample concentration may be used, provided that
all QC tests are performed and all QC acceptance criteria in this
method are met. Also add an aliquot of the surrogate spiking solution
(Section 6.7) and internal standard spiking solution (Section <IP_ADDRESS>)
to the reagent-water aliquots.
    8.2.3 Analyze the four LCSs according to the method beginning in
Section 10.
    8.2.4 Calculate the average percent recovery (x) and the standard
deviation of the percent recovery (s) for each analyte using the four
results.
    8.2.5 For each analyte, compare s and x with the corresponding
acceptance criteria for precision and recovery in Table 7. For analytes
in Tables 1 and 2 not listed in Table 7, DOC QC acceptance criteria
must be developed by the laboratory. EPA has provided guidance for
development of QC acceptance criteria (References 11 and 12). If s and
x for all analytes of interest meet the acceptance criteria, system
performance is acceptable and analysis of blanks and samples may begin.
If any individual s exceeds the precision limit or any individual x
falls outside the range for recovery, system performance is
unacceptable for that analyte.

    Note:  The large number of analytes in Tables 1 and 2 present a
substantial probability that one or more will fail at least one of
the acceptance criteria when many or all analytes are determined
simultaneously. Therefore, the analyst is permitted to conduct a
``re-test'' as described in Sec. 8.2.6.

    8.2.6 When one or more of the analytes tested fail at least one of
the acceptance criteria, repeat the test for only the analytes that
failed. If results for these analytes pass, system performance is
acceptable and analysis of samples and blanks may proceed. If one or
more of the analytes again fail, system performance is unacceptable for
the analytes that failed the acceptance criteria. Correct the problem
and repeat the test (Section 8.2). See Section 8.1.7 for disposition of
repeated failures.

    Note:  To maintain the validity of the test and re-test, system
maintenance and/or adjustment is not permitted between this pair of
tests.

    8.3 Matrix spike and matrix spike duplicate (MS/MSD)--The
laboratory must, on an ongoing basis, spike at least 5% of the samples
from each sample site being monitored in duplicate to assess accuracy
(recovery and precision). The data user should identify the sample and
the analytes of interest (Section 1.3) to be spiked. If direction
cannot be obtained, the laboratory must spike at least one sample per
batch of samples analyzed on a given 12-hour shift with the analytes in
Table 1. Spiked sample results should be reported only to the data user
whose sample was spiked, or as requested or required by a regulatory/
control authority, or in a permit.
    8.3.1 If, as in compliance monitoring, the concentration of a
specific analyte will be checked against a regulatory concentration
limit, the concentration of the spike should be at that limit;
otherwise, the concentration of the spike should be one to five times
higher than the background concentration determined in Section 8.3.2,
at or near the midpoint of the calibration range, or at the
concentration in the LCS (Section 8.4) whichever concentration would be
larger.
    8.3.2 Analyze one sample aliquot to determine the background
concentration (B) of the each analyte of interest. If necessary,
prepare a new check sample concentrate (Section 8.2.1) appropriate for
the background concentration. Spike and analyze two additional sample
aliquots, and determine the concentration after spiking (A1
and A2) of each analyte. Calculate the percent recoveries
(P1 and P2) as 100 (A1-B)/T and 100
(A2-B)/T, where T is the known true value of the spike. Also
calculate the relative percent difference (RPD) between the
concentrations (A1 and A2) as 200
[verbarlm]A1-A2 [verbarlm]/(A1 +
A2). If necessary, adjust the concentrations used to
calculate the RPD to account for differences in the volumes of the
spiked aliquots.
    8.3.3 Compare the percent recoveries (P1 and
P2) and the RPD for each analyte in the MS/MSD aliquots with
the corresponding QC acceptance criteria in Table 7. A laboratory may
develop and apply QC acceptance criteria more restrictive than the
criteria in Table 6, if desired.
    <IP_ADDRESS> If any individual P falls outside the designated range for
recovery in either aliquot, or the RPD limit is exceeded, the result
for the analyte in the unspiked sample is suspect and may not be
reported or used for permitting or regulatory compliance purposes. See
Section 8.1.7 for disposition of failures.
    <IP_ADDRESS> The acceptance criteria in Table 7 were calculated to
include an allowance for error in measurement of both the background
and spike concentrations, assuming a spike to background ratio of 5:1.
This error will be accounted for to the extent that the spike to
background ratio approaches 5:1 (Reference 13). If spiking is performed
at a concentration lower than 20 [mu]g/L, the laboratory must use
either the QC acceptance criteria in Table 7, or optional QC acceptance
criteria calculated for the specific spike concentration. To use the
optional acceptance criteria: (1) Calculate recovery (X') using the
equation in Table 8, substituting the spike concentration (T) for C;
(2) Calculate overall precision (S') using the equation in Table 8,
substituting X' for x; (3) Calculate the range for recovery at the
spike concentration as (100 X'/T)  2.44(100 S'/T)%
(Reference 4). For analytes of interest in Tables 1 and 2 not listed in
Table 7, QC acceptance criteria must be developed by the laboratory.
EPA has provided guidance for development of QC acceptance criteria
(References 11 and 12).
    8.3.4 After analysis of a minimum of 20 MS/MSD samples for each
target analyte and surrogate, the laboratory must calculate and apply
in-house QC limits for recovery and RPD of future MS/MSD samples
(Section 8.3). The QC limits for recovery are calculated as the mean
observed recovery  3 standard deviations, and the upper QC
limit for RPD is calculated as the mean RPD plus 3 standard deviations
of the RPDs. The in-house QC limits must be updated at least every two
years and re-established after any major change in the analytical
instrumentation or process. At least 80% of the analytes tested in the
MS/MSD must have in-house QC acceptance criteria that are tighter than
those in

Table 7. If an in-house QC limit for the RPD is greater than the limit
in Table 7, then the limit in Table 7 must be used. Similarly, if an
in-house lower limit for recovery is below the lower limit in Table 7,
then the lower limit in Table 7 must be used, and if an in-house upper
limit for recovery is above the upper limit in Table 7, then the upper
limit in Table 7 must be used. The laboratory must evaluate surrogate
recovery data in each sample against its in-house surrogate recovery
limits. The laboratory may use 60-140% as interim acceptance criteria
for surrogate recoveries until in-house limits are developed.
    8.4 Calibration verification/laboratory control sample (LCS)--The
working calibration curve or RF must be verified at the beginning of
each 12-hour shift by the measurement of an LCS.

    Note: The 12-hour shift begins after analysis of the blank that
follows the LCS and ends 12 hours later. The blank is outside of the
12-hour shift. The MS and MSD are treated as samples and are
analyzed within the 12-hour shift.

    8.4.1 Prepare the LCS by adding QC check sample concentrate
(Section 8.2.1) to reagent water. Include all analytes of interest
(Section 1.3) in the LCS. The LCS may be the same sample prepared for
the DOC (Section 8.2.1). The volume of reagent water must be the same
as the volume used for the sample, blank (Section 8.5), and MS/MSD
(Section 8.3). Also add an aliquot of the surrogate solution (Section
6.7) and internal standard solution (Section <IP_ADDRESS>). The
concentration of the analytes in reagent water should be the same as
the concentration in the DOC (Section 8.2.2).
    8.4.2 Analyze the LCS prior to analysis of field samples in the
batch of samples analyzed during the 12-hour shift (see the Note at
Section 8.4). Determine the concentration (A) of each analyte.
Calculate the percent recovery (Q) as 100 (A/T) %, where T is the true
value of the concentration in the LCS.
    8.4.3 Compare the percent recovery (Q) for each analyte with its
corresponding QC acceptance criterion in Table 7. For analytes of
interest in Tables 1 and 2 not listed in Table 7, use the QC acceptance
criteria developed for the MS/MSD (Section <IP_ADDRESS>). If the recoveries
for all analytes of interest fall within their respective QC acceptance
criteria, analysis of blanks and field samples may proceed. If any
individual Q falls outside the range, proceed according to Section
8.4.4.

    Note: The large number of analytes in Tables 1-2 present a
substantial probability that one or more will fail the acceptance
criteria when all analytes are tested simultaneously. Because a re-
test is allowed in event of failure (Sections 8.1.7 and 8.4.3), it
may be prudent to analyze two LCSs together and evaluate results of
the second analysis against the QC acceptance criteria only if an
analyte fails the first test.

    8.4.4 Repeat the test only for those analytes that failed to meet
the acceptance criteria (Q). If these analytes now pass, system
performance is acceptable and analysis of blanks and samples may
proceed. Repeated failure, however, will confirm a general problem with
the measurement system. If this occurs, repeat the test using a fresh
LCS (Section 8.2.2) or an LCS prepared with a fresh QC check sample
concentrate (Section 8.2.1), or perform and document system repair.
Subsequent to repair, repeat the calibration verification/LCS test
(Section 8.4). If the acceptance criteria for Q cannot be met, re-
calibrate the instrument (Section 7). If failure of the LCS indicates a
systemic problem with samples analyzed during the 12-hour shift, re-
analyze the samples analyzed during that 12-hour shift. See Section
8.1.7 for disposition of repeated failures.

    Note: To maintain the validity of the test and re-test, system
maintenance and/or adjustment is not permitted between this pair of
tests.

    8.4.5 After analysis of 20 LCS samples, the laboratory must
calculate and apply in-house QC limits for recovery to future LCS
samples (Section 8.4). Limits for recovery in the LCS are calculated as
the mean recovery 3 standard deviations. A minimum of 80%
of the analytes tested for in the LCS must have QC acceptance criteria
tighter than those in Table 7. Many of the analytes and surrogates may
not contain recommended acceptance criteria. The laboratory should use
60-140% as interim acceptance criteria for recoveries of spiked
analytes and surrogates that do not have recovery limits specified in
Table 7, until in-house LCS and surrogate limits are developed. If an
in-house lower limit for recovery is lower than the lower limit in
Table 7, the lower limit in Table 7 must be used, and if an in-house
upper limit for recovery is higher than the upper limit in Table 7, the
upper limit in Table 7 must be used.
    8.5 Blank--A blank must be analyzed at the beginning of each 12-
hour shift to demonstrate freedom from contamination. A blank must also
be analyzed after a sample containing a high concentration of an
analyte or potentially interfering compound to demonstrate freedom from
carry-over.
    8.5.1 Spike the internal standards and surrogates into the blank.
Analyze the blank immediately after analysis of the LCS (Section 8.4)
and prior to analysis of the MS/MSD and samples to demonstrate freedom
from contamination.
    8.5.2 If any analyte of interest is found in the blank: (1) at a
concentration greater than the MDL for the analyte, (2) at a
concentration greater than one-third the regulatory compliance limit,
or (3) at a concentration greater than one-tenth the concentration in a
sample analyzed during the 12-hour shift (Section 8.4), whichever is
greater; analysis of samples must be halted and samples affected by the
blank must be re-analyzed. Samples must be associated with an
uncontaminated blank before they may be reported or used for permitting
or regulatory compliance purposes.
    8.6 Surrogate recoveries--Spike the surrogates into all samples,
blanks, LCSs, and MS/MSDs. Compare surrogate recoveries against the QC
acceptance criteria in Table 7. For surrogates in Table 5 without QC
acceptance criteria in Table 7, and for other surrogates that may be
used by the laboratory, limits must be developed by the laboratory. EPA
has provided guidance for development of QC acceptance criteria
(References 11 and 12). If any recovery fails its criteria, attempt to
find and correct the cause of the failure. Surrogate recoveries from
the blank and LCS may be used as pass/fail criteria by the laboratory
or as required by a regulatory authority, or may be used to diagnose
problems with the analytical system.
    8.7 Internal standard responses.
    8.7.1 Calibration verification/LCS--The responses (GC peak heights
or areas) of the internal standards in the calibration verification/LCS
must be within 50% to 200% (\1/2\ to 2x) of their respective responses
in the mid-point calibration standard. If they are not, repeat the LCS
test using a fresh QC check sample (Section 8.4.1) or perform and
document system repair. Subsequent to repair, repeat the calibration
verification/LCS test (Section 8.4). If the responses are still not
within 50% to 200%, re-calibrate the instrument (Section 7) and repeat
the calibration verification/LCS test.
    8.7.2 Samples, blanks, and MS/MSDs--The responses (GC peak heights
or areas) of the internal standards in each sample, blank, and MS/MSD
must be within 50% to 200% (\1/2\ to 2x) of its respective response in
the most recent LCS. If, as a group, all internal standard are not
within this range, perform and document system repair, repeat the
calibration verification/LCS test

(Section 8.4), and re-analyze the affected samples. If a single
internal standard is not within the 50% to 200% range, use an alternate
internal standard for quantitation of the analyte referenced to the
affected internal standard.
    8.8 As part of the QC program for the laboratory, control charts or
statements of accuracy for wastewater samples must be assessed and
records maintained periodically (see 40 CFR 136.7(c)(1)(viii)). After
analysis of five or more spiked wastewater samples as in Section 8.3,
calculate the average percent recovery (x) and the standard deviation
of the percent recovery (sp). Express the accuracy assessment as a
percent interval from x -2sp to x +2sp. For example, if x = 90% and sp
= 10%, the accuracy interval is expressed as 70-110%. Update the
accuracy assessment for each analyte on a regular basis (e.g., after
each 5-10 new accuracy measurements).
    8.9 It is recommended that the laboratory adopt additional quality
assurance practices for use with this method. The specific practices
that are most productive depend upon the needs of the laboratory and
the nature of the samples. Field duplicates may be analyzed to assess
the precision of environmental measurements. Whenever possible, the
laboratory should analyze standard reference materials and participate
in relevant performance evaluation studies.
9. Sample Collection, Preservation, and Handling
    9.1 Collect the sample as a grab sample in a glass container having
a total volume of at least 25 mL. Fill the sample bottle just to
overflowing in such a manner that no air bubbles pass through the
sample as the bottle is being filled. Seal the bottle so that no air
bubbles are entrapped in it. If needed, collect additional sample(s)
for the MS/MSD (Section 8.3).
    9.2 Ice or refrigerate samples at <6 [deg]C from the time of
collection until analysis, but do not freeze. If residual chlorine is
present, add sodium thiosulfate preservative (10 mg/40 mL is sufficient
for up to 5 ppm Cl2) to the empty sample bottle just prior
to shipping to the sampling site. Any method suitable for field use may
be employed to test for residual chlorine (Reference 14). Field test
kits are also available for this purpose. If sodium thiosulfate
interferes in the determination of the analytes, an alternate
preservative (e.g., ascorbic acid or sodium sulfite) may be used. If
preservative has been added, shake the sample vigorously for one
minute. Maintain the hermetic seal on the sample bottle until time of
analysis.
    9.3 If acrolein is to be determined, analyze the sample within 3
days. To extend the holding time to 14 days, acidify a separate sample
to pH 4-5 with HCl using the procedure in Section 9.7.
    9.4 Experimental evidence indicates that some aromatic compounds,
notably benzene, toluene, and ethyl benzene are susceptible to rapid
biological degradation under certain environmental conditions
(Reference 3). Refrigeration alone may not be adequate to preserve
these compounds in wastewaters for more than seven days. To extend the
holding time for aromatic compounds to 14 days, acidify the sample to
approximately pH 2 using the procedure in Section 9.7.
    9.5 If halocarbons are to be determined, either use the acidified
aromatics sample in Section 9.4 or acidify a separate sample to a pH of
about 2 using the procedure in Section 9.7. Aqueous samples should not
be preserved with acid if the ethers in Table 2, or the alcohols that
they would form upon hydrolysis, are of analytes of interest.
    9.6 The ethers listed in Table 2 are prone to hydrolysis at pH 2
when a heated purge is used. Aqueous samples should not be acid
preserved if these ethers are of interest, or if the alcohols they
would form upon hydrolysis are of interest and the ethers are
anticipated to present.
    9.7 Sample acidification--Collect about 500 mL of sample in a clean
container and adjust the pH of the sample to 4-5 for acrolein (Section
9.3), or to about 2 for the aromatic compounds (Section 9.4) by adding
1+1 HCl while swirling or stirring. Check the pH with narrow range pH
paper. Fill a sample container as described in Section 9.1.
Alternatively, fill a precleaned vial (Section 5.1.1) that contains
approximately 0.25 mL of 1+1 HCl with sample as in Section 9.1. If
preserved using this alternative procedure, the pH of the sample can be
verified to be <2 after some of the sample is removed for analysis.
Acidification will destroy 2-chloroethylvinyl ether; therefore,
determine 2-chloroethylvinyl ether from the unacidified sample.
    9.8 All samples must be analyzed within 14 days of collection
(Reference 3), unless specified otherwise in Sections 9.3-9.7.
10. Sample Purging and Gas Chromatography
    10.1 The footnote to Table 3 gives the suggested GC column and
operating conditions. Included in Table 3 are retention times and MDLs
that can be achieved under these conditions. Sections 10.2 through 10.7
suggest procedures that may be used with a manual purge-and-trap
system. Auto-samplers and other columns or chromatographic conditions
may be used if requirements in this method are met.
    10.2 Attach the trap inlet to the purging device, and set the
purge-and-trap system to purge (Figure 3). Open the syringe valve
located on the purging device sample introduction needle.
    10.3 Allow the sample to come to ambient temperature prior to
pouring an aliquot into the syringe. Remove the plunger from a syringe
and attach a closed syringe valve. Open the sample bottle (or standard)
and carefully pour the sample into the syringe barrel to just short of
overflowing. Replace the syringe plunger and compress the sample. Open
the syringe valve and vent any residual air while adjusting the sample
volume. Since this process of taking an aliquot destroys the validity
of the sample for future analysis, the analyst should fill a second
syringe at this time to protect against possible loss of data. Add the
surrogate spiking solution (Section 6.7) and internal standard spiking
solution (Section <IP_ADDRESS>) through the valve bore, then close the
valve. The surrogate and internal standards may be mixed and added as a
single spiking solution. Autosamplers designed for purge-and-trap
analysis of volatiles also may be used.
    10.4 Attach the syringe valve assembly to the syringe valve on the
purging device. Open the syringe valve and inject the sample into the
purging chamber.
    10.5 Close both valves and purge the sample at a temperature, flow
rate, and duration sufficient to purge the less-volatile analytes onto
the trap, yet short enough to prevent blowing the more-volatile
analytes through the trap. The temperature, flow rate, and time should
be determined by test. The same purge temperature, flow rate, and purge
time must be used for all calibration, QC, and field samples.
    10.6 After the purge, set the purge-and-trap system to the desorb
mode (Figure 4), and begin to temperature program the gas
chromatograph. Introduce the trapped materials to the GC column by
rapidly heating the trap to the desorb temperature while backflushing
the trap with carrier gas at the flow rate and for the time necessary
to desorb the analytes of interest. The optimum temperature, flow rate,
and time should be determined by test. The

same temperature, desorb time, and flow rate must be used for all
calibration, QC, and field samples. If heating of the trap does not
result in sharp peaks for the early eluting analytes, the GC column may
be used as a secondary trap by cooling to an ambient or subambient
temperature. To avoid carry-over and interferences, maintain the trap
at the desorb temperature and flow rate until the analytes, interfering
compounds, and excess water are desorbed. The optimum conditions should
be determined by test.
    10.7 Start MS data acquisition at the start of the desorb cycle and
stop data collection when the analytes of interest, potentially
interfering compounds, and water have eluted (see the footnote to Table
3 for conditions).
    10.8 Cool the trap to the purge temperature and return the trap to
the purge mode (Figure 3). When the trap is cool, the next sample can
be analyzed.
11. Performance Tests
    11.1 At the beginning of each 12-hour shift during which analyses
are to be performed, GC/MS performance must be verified before blanks
or samples may be analyzed (Section 8.4). Use the instrument operating
conditions in the footnotes to Table 3 for these performance tests.
Alternate conditions may be used so as long as all QC requirements are
met.
    11.2 BFB--Inject 50 ng of BFB solution directly on the column.
Alternatively, add BFB to reagent water or an aqueous standard such
that 50 ng or less of BFB will be introduced into the GC. Analyze
according to Section 10. Confirm that all criteria in Section <IP_ADDRESS>
and Table 4 are met. If all criteria are not met, perform system
repair, retune the mass spectrometer, and repeat the test until all
criteria are met.
    11.3 GC resolution--There must be a valley between 1,2-
dibromoethane and chlorobenzene, and the height of the valley must not
exceed 25 percent of the shorter of the two peaks. For an alternate GC
column, apply this valley height criterion to two representative GC
peaks separated by no more than 7 seconds.
    11.4 Verify calibration with the LCS (Section 8.4) after the
criteria for BFB are met (Reference 15) and prior to analysis of a
blank or sample. After verification, analyze a blank (Section 8.5) to
demonstrate freedom from contamination and carry-over at the MDL.
12. Qualitative Identification
    12.1 Target analytes are identified by comparison of results from
analysis of a sample or blank with data stored in the GC/MS data system
(Section <IP_ADDRESS>). Identification of an analyte is confirmed per
Sections 12.1.1 through 12.1.4.
    12.1.1 The signals for all characteristic m/z's stored in the data
system (Section <IP_ADDRESS>) for each analyte of interest must be present
and must maximize within the same two consecutive scans.
    12.1.2 Based on the relative retention time (RRT), the RRT for the
analyte must be within  0.06 of the RRT of the analyte in
the LCS run at the beginning of the shift (Section 8.4). Relative
retention time is used to establish the identification window because
it compensates for small changes in the GC temperature program whereas
the absolute retention time does not (see Section <IP_ADDRESS>).

    Note: RRT is a unitless quantity (see Sec. 20.2), although some
procedures refer to ``RRT units'' in providing the specification for
the agreement between the RRT values in the sample and the LCS or
other standard.

    12.1.3 Either (1) the background corrected EICP areas, or (2) the
corrected relative intensities of the mass spectral peaks at the GC
peak maximum, must agree within 50% to 200% (\1/2\ to 2 times) for all
m/z's in the reference mass spectrum stored in the data system (Section
<IP_ADDRESS>), or from a reference library. For example, if a peak has an
intensity of 20% relative to the base peak, the analyte is identified
if the intensity of the peak in the sample is in the range of 10% to
40% of the base peak.
    12.1.4 The m/z's present in the acquired mass spectrum for the
sample that are not present in the reference mass spectrum must be
accounted for by contaminant or background m/z's. A reference library
may be helpful to identify and account for background or contaminant m/
z's. If the acquired mass spectrum is contaminated, or if
identification is ambiguous, an experienced spectrometrist (Section
1.6) must determine the presence or absence of the compound.
    12.2 Structural isomers that have very similar mass spectra can be
identified only if the resolution between authentic isomers in a
standard mix is acceptable. Acceptable resolution is achieved if the
baseline to valley height between the isomers is less than 50% of the
height of the shorter of the two peaks. Otherwise, structural isomers
are identified as isomeric pairs.
13. Calculations
    13.1 When an analyte has been identified, quantitation of that
analyte is based on the integrated abundance from the EICP of the
primary characteristic m/z in Table 5 or 6. Calculate the concentration
using the response factor (RF) determined in Section 7.3.3 and Equation
2. If a calibration curve was used, calculate the concentration using
the regression equation for the curve. If the concentration of an
analyte exceeds the calibration range, dilute the sample by the minimum
amount to bring the concentration into the calibration range, and re-
analyze. Determine a dilution factor (DF) from the amount of the
dilution. For example, if the extract is diluted by a factor of 2, DF =
2.
[GRAPHIC] [TIFF OMITTED] TP19FE15.013

Where:

Cs = Concentration of the analyte in the sample, and the
other terms are as defined in Section 7.3.3.

    13.2 Reporting of results.
    As noted in Section 1.4.1, EPA has promulgated this method at 40
CFR part 136 for use in wastewater compliance monitoring under the
National Pollutant Discharge Elimination System (NPDES). The data
reporting practices described here are focused on such monitoring needs
and may not be relevant to other uses of the method.
    13.2.1 Report results for wastewater samples in [mu]g/L without
correction for recovery. (Other units may be used if required by in a
permit.) Report all QC data with the sample results.
    13.2.2 Reporting level.
    Unless otherwise specified in by a regulatory authority or in a
discharge permit, results for analytes that meet the identification
criteria are reported down to the concentration of the ML established
by the laboratory through calibration of the instrument (see Section
7.3.2 and the glossary for the derivation of the ML). EPA considers the
terms ``reporting limit,'' ``quantitation limit,'' and ``minimum
level'' to be synonymous.
    <IP_ADDRESS> Report a result for each analyte in each sample, blank, or
standard at or above the ML to 3 significant figures. Report a result
for each analyte found in each sample below the ML as ``12, are hazardous and must be
neutralized before being poured down a drain, or must be handled and
disposed of as hazardous waste.
    16.3 Many analytes in this method decompose above 500 [deg]C. Low-
level waste such as absorbent paper, tissues, and plastic gloves may be
burned in an appropriate incinerator. Gross quantities of neat or
highly concentrated solutions of toxic or hazardous chemicals should be
packaged securely and disposed of through commercial or governmental
channels that are capable of handling these types of wastes.
    16.4 For further information on waste management, consult The Waste
Management Manual for Laboratory Personnel and Less is Better-
Laboratory Chemical Management for Waste Reduction, available from the
American Chemical Society's Department of Government Relations and
Science Policy, 1155 16th Street NW., Washington, DC 20036, 202/872-
4477.
17. References
1. Bellar, T.A. and Lichtenberg, J.J. ``Determining Volatile
Organics at Microgram-per-Litre Levels by Gas Chromatography,''
Journal American Water Works Association, 66, 739 (1974).
2. ``Sampling and Analysis Procedures for Screening of Industrial
Effluents for Priority Pollutants,'' U.S. Environmental Protection
Agency, Environmental Monitoring and Support Laboratory, Cincinnati,
Ohio 45268, March 1977, Revised April 1977.
3. Bellar, T.A. and Lichtenberg, J.J. ``Semi-Automated Headspace
Analysis of Drinking Waters and Industrial Waters for Purgeable
Volatile Organic Compounds,'' Measurement of Organic Pollutants in
Water and Wastewater, C.E. Van Hall, editor, American Society for
Testing and Materials, Philadelphia, PA. Special Technical
Publication 686, 1978.
4. ``EPA Method Study 29 EPA Method 624-Purgeables,'' EPA 600/4-84-
054, National Technical Information Service, PB84-209915,
Springfield, Virginia 22161, June 1984.
5. 40 CFR part 136, appendix B.
6. ``Method Detection Limit for Methods 624 and 625,'' Olynyk, P.,
Budde, W.L., and Eichelberger, J.W. Unpublished report, May 14,
1980.
7. ``Carcinogens-Working With Carcinogens,'' Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, August 1977.
8. ``OSHA Safety and Health Standards, General Industry,'' (29 CFR
part 1910), Occupational Safety and Health Administration, OSHA 2206
(Revised, January 1976).
9. ``Safety in Academic Chemistry Laboratories,'' American Chemical
Society Publication, Committee on Chemical Safety, 7th Edition,
2003.
10. 40 CFR 136.6(b)(5)(x).
11. 40 CFR 136.6(b)(2)(i).
12. Protocol for EPA Approval of New Methods for Organic and
Inorganic Analytes in Wastewater and Drinking Water (EPA-821-B-98-
003) March 1999
13. Provost, L.P. and Elder, R.S. ``Interpretation of Percent
Recovery Data,'' American Laboratory, 15, 58-63 (1983).
14. 40 CFR 136.3(a), Table IB, Chlorine--Total residual
15. Budde, W.L. and Eichelberger, J.W. ``Performance Tests for the
Evaluation of Computerized Gas Chromatography/Mass Spectrometry
Equipment and Laboratories,'' EPA-600/4-80-025, U.S. Environmental
Protection Agency, Environmental Monitoring and Support Laboratory,
Cincinnati, Ohio 45268, April 1980.
16. ``Method Performance Data for Method 624,'' Memorandum from R.
Slater and T. Pressley, U.S. Environmental Protection Agency,
Environmental Monitoring and Support Laboratory, Cincinnati, Ohio
45268, January 17, 1984.
18. Tables

                                             Table 1--Purgeables \1\
----------------------------------------------------------------------------------------------------------------
                        Analyte                           CAS Registry No.  MDL ([mu]g/L) \2\   ML ([mu]g/L) \3\
----------------------------------------------------------------------------------------------------------------
Acrolein...............................................           107-02-8
Acrylonitrile..........................................           107-13-1
Benzene................................................            71-43-2                4.4               13.2
Bromodichloromethane...................................            75-27-4                2.2                6.6
Bromoform..............................................            75-25-2                4.7               14.1
Bromomethane...........................................            74-83-9
Carbon tetrachloride...................................            56-23-5                2.8                8.4
Chlorobenzene..........................................           108-90-7                6.0               18.0
Chloroethane...........................................            75-00-3
2-Chloroethylvinyl ether...............................           110-75-8
Chloroform.............................................            67-66-3                1.6                4.8
Chloromethane..........................................            74-87-3
Dibromochloromethane...................................           124-48-1                3.1                9.3
1,2-Dichlorobenzene....................................            95-50-1
1,3-Dichlorobenzene....................................           541-73-1
1,4-Dichlorobenzene....................................           106-46-7
1,1-Dichloroethane.....................................            75-34-3                4.7               14.1
1,2-Dichloroethane.....................................           107-06-2                2.8                8.4
1,1-Dichloroethene.....................................            75-35-4                2.8                8.4
trans-1,2-Dichloroethene...............................           156-60-5                1.6                4.8
1,2-Dichloropropane....................................            78-87-5                6.0               18.0
cis-1,3-Dichloropropene................................         10061-01-5                5.0               15.0
trans-1,3-Dichloropropene..............................         10061-02-6
Ethyl benzene..........................................           100-41-4                7.2               21.6
Methylene chloride.....................................            75-09-2                2.8                8.4
1,1,2,2-Tetrachloroethane..............................            79-34-5                6.9               20.7
Tetrachloroethene......................................           127-18-4                4.1               12.3
Toluene................................................           108-88-3                6.0               18.0
1,1,1-Trichloroethane..................................            71-55-6                3.8               11.4
1,1,2-Trichloroethane..................................            79-00-5                5.0               15.0
Trichloroethene........................................            79-01-6                1.9                5.7
Vinyl chloride.........................................            75-01-4
----------------------------------------------------------------------------------------------------------------
\1\ All the analytes in this table are Priority Pollutants (40 CFR part 423, appendix A)
\2\ MDL values from the 1984 promulgated version of Method 624
\3\ ML = Minimum Level--see Glossary for definition and derivation

                     Table 2--Additional Purgeables
------------------------------------------------------------------------
                         Analyte                           CAS Registry
------------------------------------------------------------------------
Acetone \1\.............................................         67-64-1
Acetonitrile \2\........................................         75-05-8
Allyl alcohol \1\.......................................        107-18-6
Allyl chloride..........................................        107-05-1
t-Amyl ethyl ether (TAEE)...............................        919-94-8
t-Amyl methyl ether (TAME)..............................         994-058
Benzyl chloride.........................................        100-44-7
Bromoacetone \2\........................................        598-31-2
Bromobenzene............................................        108-86-1
Bromochloromethane......................................         74-97-5
1,3-Butadiene...........................................        106-99-0
n-Butanol \1\...........................................         71-36-3
2-Butanone (MEK) 1 2....................................         78-93-3
t-Butyl alcohol (TBA)...................................         75-65-0
n-Butylbenzene..........................................        104-51-8
sec-Butylbenzene........................................        135-98-8
t-Butylbenzene..........................................         98-06-6
t-Butyl ethyl ether (ETBE)..............................        637-92-3
Carbon disulfide........................................         75-15-0
Chloral hydrate \2\.....................................        302-17-0
Chloroacetonitrile \1\..................................        107-14-2
1-Chlorobutane..........................................        109-69-3
Chlorodifluoromethane...................................         75-45-6
2-Chloroethanol \ 2\....................................        107-07-3
bis (2-Chloroethyl) sulfide \ 2\........................        505-60-2
1-Chlorohexanone........................................      20261-68-1
Chloroprene (2-chloro-1,3-butadiene)....................        126-99-8
3-Chloropropene.........................................        107-05-1
3-Chloropropionitrile...................................        542-76-7
2-Chlorotoluene.........................................         95-49-8
4-Chlorotoluene.........................................        106-43-4
Crotonaldehyde 1 2......................................        123-73-9
Cyclohexanone...........................................        108-94-1
1,2-Dibromo-3-chloropropane.............................         96-12-8
1,2-Dibromoethane.......................................        106-93-4
Dibromomethane..........................................         74-95-3
cis-1,4-Dichloro-2-butene...............................       1476-11-5
trans-1,4-Dichloro-2-butene.............................        110-57-6
cis-1,2-Dichloroethene..................................        156-59-2
Dichlorodifluoromethane.................................         75-71-8
1,3-Dichloropropane.....................................        142-28-9
2,2-Dichloropropane.....................................        590-20-7
1,3-Dichloro-2-propanol \2\.............................         96-23-1
1,1-Dichloropropene.....................................        563-58-6
cis-1,3-Dichloropropene.................................      10061-01-5
1:2,3:4-Diepoxybutane...................................       1464-53-5
Diethyl ether...........................................         60-29-7
Diisopropyl ether (DIPE)................................        108-20-3
1,4-Dioxane \2\.........................................        123-91-1
Epichlorohydrin \2\.....................................        106-89-8
Ethanol \2\.............................................         64-17-5
Ethyl acetate \2\.......................................        141-78-6
Ethyl methacrylate......................................         97-63-2
Ethylene oxide \2\......................................         75-21-8
Hexachlorobutadiene.....................................         87-63-3
Hexachloroethane........................................         67-72-1
2-Hexanone \2\..........................................        591-78-6
Iodomethane.............................................         74-88-4
Isobutyl alcohol \1\....................................         78-83-1
Isopropylbenzene........................................         98-82-8
p-Isopropyltoluene......................................         99-87-6
Methacrylonitrile \2\...................................        126-98-7
Methanol \2\............................................         67-56-1
Malonitrile \2\.........................................        109-77-3
Methyl acetate..........................................         79-20-9
Methyl acrylate.........................................         96-33-3
Methyl cyclohexane......................................        108-87-2
Methyl iodide...........................................         74-88-4
Methyl methacrylate.....................................         78-83-1
4-Methyl-2-pentanone (MIBK) \2\.........................        108-10-1
Methyl-t-butyl ether (MTBE).............................       1634-04-4
Naphthalene.............................................         91-20-3
Nitrobenzene............................................         98-95-3
N-Nitroso-di-n-butylamine \2\...........................        924-16-3
2-Nitropropane..........................................         79-46-9
Paraldehyde \2\.........................................        123-63-7
Pentachloroethane \2\...................................         76-01-7
Pentafluorobenzene......................................        363-72-4
2-Pentanone \2\.........................................        107-19-7
2-Picoline \2\..........................................        109-06-8
1-Propanol \1\..........................................         71-23-8
2-Propanol \1\..........................................         67-63-0
Propargyl alcohol \2\...................................        107-19-7
beta-Propiolactone \2\..................................         57-58-8
Propionitrile (ethyl cyanide) \1\.......................        107-12-0
n-Propylamine...........................................        107-10-8
n-Propylbenzene.........................................        103-65-1
Pyridine \2\............................................        110-86-1

Styrene.................................................        100-42-5
1,1,1,2-Tetrachloroethane...............................        630-20-6
Tetrahydrofuran.........................................        109-99-9
o-Toluidine \2\.........................................         95-53-4
1,2,3-Trichlorobenzene..................................         87-61-6
Trichlorofluoromethane..................................         75-69-4
1,2,3-Trichloropropane..................................         96-18-4
1,2,3-Trimethylbenzene..................................        526-73-8
1,2,4-Trimethylbenzene..................................         95-63-6
1,3,5-Trimethylbenzene..................................        108-67-8
Vinyl acetate...........................................        108-05-4
m-Xylene \3\............................................        108-38-3
o-Xylene \3\............................................         95-47-6
p-Xylene \3\............................................        106-42-3
m+o- Xylene \3\.........................................     179601-22-0
m+p- Xylene \3\.........................................     179601-23-1
o+p- Xylene \3\.........................................     136777-61-2
------------------------------------------------------------------------
\1\ Determined at a purge temperature of 80 [deg]C.
\2\ May be detectable at a purge temperature of 80 [deg]C.
\3\ Determined in combination separated by GC column. Most GC columns
  will resolve o-xylene from m+p-xylene. Report using the CAS number for
  the individual xylene or the combination, as determined.

                    Table 3--Example Retention Times
------------------------------------------------------------------------
                                                              Retention
                          Analyte                             time (min)
------------------------------------------------------------------------
Chloromethane..............................................         3.68
Vinyl chloride.............................................         3.92
Bromomethane...............................................         4.50
Chloroethane...............................................         4.65
Trichlorofluoromethane.....................................         5.25
Diethyl ether..............................................         5.88
Acrolein...................................................         6.12
1,1-Dichloroethene.........................................         6.30
Acetone....................................................         6.40
Iodomethane................................................         6.58
Carbon disulfide...........................................         6.72
3-Chloropropene............................................         6.98
Methylene chloride.........................................         7.22
Acrylonitrile..............................................         7.63
trans-1,2-Dichloroethene...................................         7.73
1,1-Dichloroethane.........................................         8.45
Vinyl acetate..............................................         8.55
Allyl alcohol..............................................         8.58
2-Chloro-1,3-butadiene.....................................         8.65
Methyl ethyl ketone........................................         9.50
cis-1,2-Dichloroethene.....................................         9.50
Ethyl cyanide..............................................         9.57
Methacrylonitrile..........................................         9.83
Chloroform.................................................        10.05
1,1,1-Trichloroethane......................................        10.37
Carbon tetrachloride.......................................        10.70
Isobutanol.................................................        10.77
Benzene....................................................        10.98
1,2-Dichloroethane.........................................        11.00
Crotonaldehyde.............................................        11.45
Trichloroethene............................................        12.08
1,2-Dichloropropane........................................        12.37
Methyl methacrylate........................................        12.55
p-Dioxane..................................................        12.63
Dibromomethane.............................................        12.65
Bromodichloromethane.......................................        12.95
Chloroacetonitrile.........................................        13.27
2-Chloroethylvinyl ether...................................        13.45
cis-1,3-Dichloropropene....................................        13.65