Improving CHN measurements in carbonate-rich marine sediments
Stephen C. Phillips, Joel E. Johnson, Eduardo Miranda, Corinne
Disenhof  Limnol. Oceanogr. Methods 9:194-203 (2011) | DOI:
10.4319/lom.2011.9.194  ABSTRACT: CHN elemental analysis is a
common and effective method for determining total carbon (TC),
total organic carbon (TOC), inorganic carbon (IC) by difference,
and total nitrogen (TN) in marine sediments. In this article, we
identify and describe three problems related to CHN measurement
in carbonate-rich (>30% CaCO3) marine sediments and suggest
mitigation methods to obtain the most accurate measurements of
TC, TOC, IC, and TN. These problems involve (1) sample size
limitations, (2) incomplete carbonate digestion during in-situ
acid addition, and (3) nitrogen contamination during acid
additions. Carbonate-rich marine sediments often have low TOC
and TN content and are susceptible to incomplete combustion, due
to their high IC (CaCO3) content, and require careful sample
size selection to optimize