4,4'-DDE........................................................         72-55-9               4              12
4,4'-DDT........................................................         50-29-3              12              36
Dieldrin........................................................         60-57-1               2               6
Endosulfan I....................................................        959-98-8              14              42
Endosulfan II...................................................      33213-65-9               4              12
Endosulfan sulfate..............................................       1031-07-8              66             198
Endrin..........................................................         72-20-8               6              18
Endrin aldehyde.................................................       7421-93-4              23              70
Heptachlor......................................................         76-44-8               3               9
Heptachlor epoxide..............................................       1024-57-3              83             249
----------------------------------------------------------------------------------------------------------------
\1\ All analytes in this table are Priority Pollutants (40 CFR part 423, appendix A).
\2\ 40 CFR part 136, appendix B, June 30, 1986.
\3\ ML = Minimum Level--see Glossary for definition and derivation, calculated as 3 times the MDL.
\4\ MDL based on the MDL for Chlordane.

                                          Table 2--Additional Analytes
----------------------------------------------------------------------------------------------------------------
                             Analyte                                  CAS No.     MDL \3\ (ng/L)   ML \4\ (ng/L)
----------------------------------------------------------------------------------------------------------------
Acephate........................................................      30560-19-1  ..............  ..............
Alachlor........................................................      15972-60-8  ..............  ..............
Atrazine........................................................       1912-24-9  ..............  ..............
Benfluralin (Benefin)...........................................       1861-40-1  ..............  ..............
Bromacil........................................................        314-40-9  ..............  ..............
Bromoxynil octanoate............................................       1689-99-2  ..............  ..............
Butachlor.......................................................      23184-66-9  ..............  ..............
Captafol........................................................       2425-06-1  ..............  ..............
Captan..........................................................        133-06-2  ..............  ..............
Carbophenothion (Trithion)......................................        786-19-6  ..............  ..............
Chlorobenzilate.................................................        510-15-6  ..............  ..............
Chloroneb (Terraneb)............................................       2675-77-6  ..............  ..............
Chloropropylate (Acaralate).....................................       5836-10-2  ..............  ..............
Chlorothalonil..................................................       1897-45-6  ..............  ..............
Cyanazine.......................................................      21725-46-2  ..............  ..............
DCPA (Dacthal)..................................................       1861-32-1  ..............  ..............
2,4'-DDD........................................................         53-19-0  ..............  ..............
2,4'-DDE........................................................       3424-82-6  ..............  ..............
2,4'-DDT........................................................        789-02-6  ..............  ..............
Diallate (Avadex)...............................................       2303-16-4  ..............  ..............
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  ..............  ..............
Ethalfluralin (Sonalan).........................................      55283-68-6  ..............  ..............
Etridiazole.....................................................       2593-15-9  ..............  ..............
Fenarimol (Rubigan).............................................      60168-88-9  ..............  ..............
Hexachlorobenzene \1\...........................................        118-74-1  ..............  ..............
Hexachlorocyclopentadiene \1\...................................         77-47-4  ..............  ..............
Isodrin.........................................................        465-73-6  ..............  ..............
Isopropalin (Paarlan)...........................................      33820-53-0  ..............  ..............
Kepone..........................................................        143-50-0  ..............  ..............
Methoxychlor....................................................         72-43-5  ..............  ..............
Metolachlor.....................................................      51218-45-2  ..............  ..............
Metribuzin......................................................      21087-64-9  ..............  ..............
Mirex...........................................................       2385-85-5  ..............  ..............
Nitrofen (TOK)..................................................       1836-75-5  ..............  ..............
cis-Nonachlor...................................................       5103-73-1  ..............  ..............
trans-Nonachlor.................................................      39765-80-5  ..............  ..............
Norfluorazon....................................................      27314-13-2  ..............  ..............
Octachlorostyrene...............................................      29082-74-4  ..............  ..............
Oxychlordane....................................................      27304-13-8  ..............  ..............
PCNB (Pentachloronitrobenzene)..................................         82-68-8  ..............  ..............
Pendamethalin (Prowl)...........................................      40487-42-1  ..............  ..............
cis-Permethrin..................................................      61949-76-6  ..............  ..............
trans-Permethrin................................................      61949-77-7  ..............  ..............
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  ..............  ..............
Strobane........................................................       8001-50-1  ..............  ..............
Technazene......................................................        117-18-0  ..............  ..............
Technical Chlordane \2\.........................................  ..............  ..............  ..............
Terbacil........................................................       5902-51-2  ..............  ..............
Terbuthylazine..................................................       5915-41-3  ..............  ..............
Toxaphene \1\...................................................       8001-35-2             240             720
Trifluralin.....................................................       1582-09-8  ..............  ..............
PCB-1016 \1\....................................................      12674-11-2  ..............  ..............
PCB-1221 \1\....................................................      11104-28-2  ..............  ..............
PCB-1232 \1\....................................................      11141-16-5  ..............  ..............
PCB-1242 \1\....................................................      53469-21-9              65              95
PCB-1248 \1\....................................................      12672-29-6  ..............  ..............
PCB-1254 \1\....................................................      11097-69-1  ..............  ..............
PCB-1260 \1\....................................................      11096-82-5  ..............  ..............
PCB-1268........................................................      11100-14-4  ..............  ..............
----------------------------------------------------------------------------------------------------------------
\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, June 30, 1986.
\4\ ML = Minimum Level--see Glossary for definition and derivation, calculated as 3 times the MDL.

                  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-1016................................  ..............  ..............
PCB-1221................................  ..............  ..............
PCB-1232................................  ..............  ..............
PCB-1242................................  ..............  ..............
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/MSD
                                                                (%)          ([mu]g/L)          SD)             (%)             (%)           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 for the DOC (section 8.2.4).
X = Average of four recovery measurements for the DOC (section 8.2.4).
P = Recovery for the LCS (section 8.4.3).
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.

                Table 7--Suggested Calibration Groups \1\
------------------------------------------------------------------------
                                 Analyte
-------------------------------------------------------------------------
Calibration Group 1:
    Acephate
    Alachlor
    Atrazine
    beta-BHC
    Bromoxynil octanoate
    Captafol
    Diallate
    Endosulfan sulfate
    Endrin
    Isodrin
    Pendimethalin (Prowl)
    trans-Permethrin
Calibration Group 2:
    alpha-BHC
    DCPA
    4,4'-DDE
    4,4'-DDT
    Dichlone
    Ethalfluralin
    Fenarimol
    Methoxychlor
    Metribuzin
Calibration Group 3:
    gamma-BHC (Lindane)
    gamma-Chlordane
    Endrin ketone
    Heptachlor epoxide
    Isopropalin
    Nitrofen (TOK)
    PCNB
    cis-Permethrin
    Trifluralin
Callibration Group 4:
    Benfluralin
    Chlorobenzilate
    Dieldrin
    Endosulfan I
    Mirex
    Terbacil
    Terbuthylazine
    Triadimefon
Calibration Group 5:
    alpha-Chlordane
    Captan
    Chlorothalonil
    4,4'-DDD
    Norfluorazon
    Simazine
Calibration Group 6:
    Aldrin
    delta-BHC
    Bromacil
    Butachlor
    Endosulfan II
    Heptachlor
    Kepone
Calibration Group 7:
    Carbophenothion
    Chloroneb
    Chloropropylate
    DBCP
    Dicofol
    Endrin aldehyde
    Etridiazone
    Perthane
    Propachlor
    Propanil
    Propazine
------------------------------------------------------------------------
\1\ The analytes may be organized in other calibration groups, provided
  that there are no coelution problems and that all QC requirements are
  met.

22. Figures

BILLING CODE 6560-50-P

[GRAPHIC] [TIFF OMITTED] TR28AU17.010

[GRAPHIC] [TIFF OMITTED] TR28AU17.011

BILLING CODE 6560-50-C

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
[mu]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 standard (section 6.8.4)
used to verify calibration (sections 7.8 and 13.6).
    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 section 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.
    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 ether.............           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, and on an interlaboratory method validation study (Reference
4). Although this method was validated through an interlaboratory
study conducted in the early 1980s, 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. 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. 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. After
purging is completed, the trap is heated and backflushed with the
gas to desorb the purgeables onto a gas chromatographic column. 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 initially
and with each analytical batch (samples analyzed on a given 12-hour
shift, to a maximum of 20 samples), 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 (Fisher #13075 or equivalent). Unless pre-
cleaned, detergent wash, rinse with tap and reagent water, and dry
at 105  5 [deg]C before use.
    5.1.2 Septum--Fluoropolymer-faced silicone (Fisher #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 with
autosamplers. 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.
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). 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.
    5.2.4 The purge-and-trap system may be assembled as a separate
unit or coupled to a gas chromatograph.
    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 alternative 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.
    6.3.4 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 or international standard, when
available. Stock solution concentrations alternative 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. Unless stated otherwise in this method,
store non-aqueous standards in fluoropolymer-lined screw-cap, or
heat-sealed, glass containers, in the dark at -20 to -10 [deg]C.
Store aqueous standards; e.g., the aqueous LCS (section 8.4.1) in
the dark at <=6 [deg]C (but do not freeze) with zero headspace;
e.g., in VOA vials (section 5.1.1). Standards prepared by the
laboratory may be stored for up to one month, except when comparison
with QC check standards indicates that a standard has degraded or
become more concentrated due to evaporation, or unless the
laboratory has data on file to prove stability for a longer period.
Commercially prepared standards may be stored until the expiration
date provided by the vendor, except when comparison with QC check
standards indicates that a standard has degraded or become more
concentrated due to evaporation, or unless the laboratory has data
from the vendor on file to prove stability for a longer period.
    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. Prepare the spiking solution such that spiking a small volume
will result in a constant concentration of the surrogates. For
example, add 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 to produce a concentration of 30 [mu]g/L for each
surrogate. Other surrogate concentrations may be used. Store per
section 6.5.4.
    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.

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 after each analysis at a
temperature and time sufficient to prevent detectable concentrations
of the analytes or contaminants in successive analyses.
    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 measurements
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 in methanol as described in Section 6.5, and prepare a
solution for spiking the internal standards into all blanks, LCSs,
and MS/MSDs. Prepare the spiking solution such that spiking a small
volume will result in a constant concentration of the internal
standards. For example, add 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 to produce 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
per section 6.5.4.
    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, but no fewer than 3 levels may be used, and only the highest or
lowest point(s) may be dropped from the calibration. One of the
calibration standards should be at a concentration at or below the
ML or as specified by a regulatory/control authority or in a permit.
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 produced in the laboratory or obtained from a
commercial vendor, again, provided that the ML value 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 = 0) 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. 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. Once the scan conditions are
established, they must be used for analyses of all standards,
blanks, and samples.

    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 alternative 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.
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. Refer to the footnotes to Table 3 for establishing
operating conditions and to section <IP_ADDRESS> for establishing scan
conditions.
    <IP_ADDRESS> For combined scan and SIM operation, set up the scan
segments and descriptors to meet requirements in sections <IP_ADDRESS>-
<IP_ADDRESS>. Analyze unfamiliar samples in the scan mode to assure that
the analytes of interest are determined.
    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] TR28AU17.012

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. On a
continuing basis, the laboratory must repeat demonstration of
capability (DOC) at least annually.
    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 alternative purge-and-trap device, and
changes in both column and type of mass spectrometer (see 40 CFR
136.6(b)(4)(xvi)). Alternative 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 8.8).
    <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 the MDLs 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 alternative 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 publicly owned treatment works (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 https://www.epa.gov/eg/industrial-effluent-guidelines for a list of industrial categories with existing
effluent guidelines).
    (i) At least one of the above wastewater matrix types must have
at least one of the following characteristics:
    (A) Total suspended solids greater than 40 mg/L.
    (B) Total dissolved solids greater than 100 mg/L.
    (C) Oil and grease greater than 20 mg/L.
    (D) NaCl greater than 120 mg/L.
    (E) CaCO3 greater than 140 mg/L.
    (ii) Results of MS/MSD tests must meet QC acceptance criteria in
section 8.3.
    (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, and business 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 Each 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 samples to monitor and evaluate method and laboratory
performance on the sample matrix. 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 must 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 must document and report the failures
(e.g., as qualifiers on results), unless the failures are not
required to be reported as determined by the regulatory/control
authority. Results associated with a QC failure for an analyte
regulated in a discharge cannot be used to demonstrate regulatory
compliance. QC failures do not relieve a discharger or permittee of
reporting timely results.
    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 (LCS
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). Alternatively, acceptance criteria for analytes not listed
in Table 7 may be based on laboratory control charts. 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 section 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
purpose of the MS/MSD requirement is to provide data that
demonstrate the effectiveness of the method as applied to the
samples in question by a given laboratory, and both the data user
(discharger, permittee, regulated entity, regulatory/control
authority, customer, other) and the laboratory share responsibility
for provision of such data. The data user should identify the sample
and the analytes of interest (section 1.3) to be spiked and provide
sufficient sample volume to perform MS/MSD analyses. The laboratory
must, on an ongoing basis, spike at least 5% of the samples in
duplicate from each discharge being monitored to assess accuracy
(recovery and precision). If direction cannot be obtained from the
data user, the laboratory must spike at least one sample in
duplicate per extraction batch of up to 20 samples 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 mid-point 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 A1-A2/
(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 7, 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. 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) and is applied to
spike concentrations of 20 [mu]g/L and higher. If spiking is
performed at a concentration lower than 20 [mu]g/L, the laboratory
must use the QC acceptance criteria in Table 7, the optional QC
acceptance criteria calculated for the specific spike concentration
in Table 8, or optional in-house criteria (Section 8.3.4). To use
the acceptance criteria in Table 8: (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).
Alternatively, acceptance criteria may be based on laboratory
control charts. In-house LCS QC acceptance criteria must be updated
at least every two years.
    8.3.4 After analysis of a minimum of 20 MS/MSD samples for each
target analyte and surrogate, and if the laboratory chooses to
develop and apply in-house QC limits, the laboratory should
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. If
in-house QC limits are developed, 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 and the remaining analytes (those
other than the analytes included in the 80%) must meet the
acceptance criteria 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.
    8.4 Calibration verification/laboratory control sample (LCS)--
The working calibration curve or RF must be verified immediately
after calibration and at the beginning of each 12-hour shift by the
measurement of an LCS. The LCS must be from a source different from
the source used for calibration (section <IP_ADDRESS>), but may be the
same as the sample prepared for the DOC (section 8.2.1).
    Note: The 12-hour shift begins after analysis of BFB, the LCS,
and the blank, and ends 12 hours later. BFB, the LCS, and blank are
outside of the 12-hour shift (Section 11.4). 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 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 LCS (section 8.4.5). 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
(section 8.4.2). 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). 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 the pair of
tests.

    8.4.5 After analysis of 20 LCS samples, and if the laboratory
chooses to develop and apply in-house QC limits, the laboratory
should calculate and apply in-house QC limits for recovery to future
LCS samples (section 8.4). Limits for recovery in the LCS 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, and the remaining analytes
(those other than the analytes included in the 80%) must meet the
acceptance criteria in Table 7. 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. Many of the analytes and surrogates do not have
acceptance criteria. The laboratory should use 60-140% as interim
acceptance criteria for recoveries of spiked analytes that do not
have recovery limits specified in Table 7, and least 80% of the
analytes should meet the 60-140% interim criteria until in-house LCS
limits are developed. Alternatively, acceptance criteria for
analytes that do not have recovery limits in Table 7 may be based on
laboratory control charts. In-house QC acceptance criteria must be
updated at least every two years.
    8.5 Blank--A blank must be analyzed prior to 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: At a
concentration greater than the MDL for the analyte, at a
concentration greater than one-third the regulatory compliance
limit, or 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. If, however,
continued re-testing results in repeated blank contamination, the
laboratory must document and report the failures (e.g., as
qualifiers on results), unless the failures are not required to be
reported as determined by the regulatory/control authority. Results
associated with blank contamination for an analyte regulated in a
discharge cannot be used to demonstrate regulatory compliance. QC
failures do not relieve a discharger or permittee of reporting
timely results.
    8.6 Surrogate recoveries--The laboratory must evaluate surrogate
recovery data in each sample against its in-house surrogate recovery
limits for surrogates that do not have acceptance criteria in Table
7. The laboratory may use 60-140% as interim acceptance criteria for
recoveries for surrogates not listed in Table 5. At least 80% of the
surrogates must meet the 60-140% interim criteria until in-house
limits are developed. Alternatively, surrogate recovery limits may
be developed from laboratory control charts.
    8.6.1 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). Alternatively, surrogate recovery limits may
be developed from laboratory control charts. In-house QC acceptance
criteria must be updated at least every two years.
    8.6.2 If any recovery fails its criteria, attempt to find and
correct the cause of the failure. See section 8.1.7 for disposition
of failures.
    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 each internal standard in each sample, blank,
and MS/MSD must be within 50% to 200% (1/2 to 2x) of its respective
response in the mid-point calibration standard. If, as a group, all
internal standards 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 alternative
internal standard for quantitation of the analyte referenced to the
affected internal standard. It may be necessary to use the data
system to calculate a new response factor from calibration data for
the alternative internal standard/analyte pair. If an internal
standard fails the 50-200% criteria and no analytes are detected in
the sample, ignore the failure or report it if required by the
regulatory/control authority.
    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 (Px)
and the standard deviation of the percent recovery (sp). Express the
accuracy assessment as a percent interval from Px-
2sp to Px + 2sp. For example, if
Px = 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). If
desired, statements of accuracy for laboratory performance,
independent of performance on samples, may be developed using LCSs.
    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 alternative 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.
    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 MDLs and MLs for many of the analytes are given
in Table 1. Retention times for many of the analytes are given in
Table 3. 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. Prior to performing analyses, and between
analyses, it may be necessary to bake the purge-and-trap and GC
systems (section 3.3).
    10.2 Attach the trap inlet to the purging device, and set the
purge-and-trap system to purge. 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, and begin the temperature program of 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. 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
standards or samples will be analyzed, perform the tests in sections
11.2-11.3 to verify system performance. Use the instrument operating
conditions in the footnotes to Table 3 for these performance tests.
Alternative 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 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.
Tests for BFB, the LCS, and the blank are outside of the 12-hour
shift, and the 12-hour shift includes samples and matrix spikes and
matrix spike duplicates (section 8.4). The total time for analysis
of BFB, the LCS, the blank, and the 12-hour shift must not exceed 14
hours.

12. Qualitative Identification

    12.1 Identification is accomplished 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 the quantitation and secondary 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 The retention time for the analyte should be within
 10 seconds of the analyte in the LCS run at the
beginning of the shift (section 8.4).

    Note:  Retention time windows other than  10 seconds
may be appropriate depending on the performance of the gas
chromatograph or observed retention time drifts due to certain types
of matrix effects. Relative retention time (RRT) may be used as an
alternative to absolute retention times if retention time drift is a
concern. RRT is a unitless quantity (see section 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. When significant retention time
drifts are observed, dilutions or spiked samples may help the
analyst determine the effects of the matrix on elution of the target
analytes and to assist in qualitative identification.

    12.1.3 Either the background corrected EICP areas, or 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
the quantitation and secondary 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 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 produce very similar mass spectra
should be identified as individual isomers if they have sufficiently
different gas chromatographic retention times. Sufficient gas
chromatographic resolution is achieved if the height of the valley
between two isomer peaks is less than 50% of the average of the two
peak heights. Otherwise, structural isomers are identified as
isomeric pairs. The resolution should be verified on the mid-point
concentration of the initial calibration as well as the laboratory
designated continuing calibration verification level if closely
eluting isomers are to be reported.

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] TR28AU17.013

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 this 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 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,'' ``limit of quantitation,'' ``quantitation limit,'' and
``minimum level'' to be synonymous.
    <IP_ADDRESS> Report a result for each analyte in each field sample
or QC standard at or above the ML to 3 significant figures. Report a
result for each analyte found in each field sample or QC standard
below the ML as ``12, are hazardous and must be
handled and disposed of as hazardous waste, or neutralized and
disposed of in accordance with all federal, state, and local
regulations. It is the laboratory's responsibility to comply with
all federal, state, and local regulations governing waste
management, particularly the hazardous waste identification rules
and land disposal restrictions. The laboratory using this method has
the responsibility to protect the air, water, and land by minimizing
and controlling all releases from fume hoods and bench operations.
Compliance is also required with any sewage discharge permits and
regulations. For further information on waste management, see ``The
Waste Management Manual for Laboratory Personnel,'' also available
from the American Chemical Society at the address in Section 15.3.
    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
``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,<PHONE_NUMBER>.

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\
----------------------------------------------------------------------------------------------------------------
                                                                   CAS Registry    MDL ([mu]g/L)   ML ([mu]g/L)
                             Analyte                                    No.             \2\             \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
Acrolein................................................        107-02-8
Acrylonitrile...........................................        107-13-1
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