Rapid One‐Step Method for Total Fatty Acids in Soils and Sediments

Abstract

In this study, a method was developed to extract and methylate total fatty acids (TFA) from soils and sediments using an acid‐catalyzed esterification–transesterification approach; the TFA method was compared with other methods in common use for fatty acids in soils. The developed method was significantly more successful in the extraction and methylation of total soil and sediment fatty acids than other methods. It also extracted long‐chain hydrocarbons from soils and sediments. The TFA method is relatively simple and rapid, has high reproducibility, substantially reduced solvent use, and can easily accommodate a large number of samples at the same time. The optimized TFA method is based on a combined “one‐step” acid‐catalyzed approach often used for biological tissues, oils, feedstuff, and leafy materials. Acid‐catalyzed methylation is effective under many conditions, and methylates all fatty acids, including free fatty acids, fatty acid esters and amides, and fatty acid salts via both esterification and transesterification pathways. Used in conjunction with other methods, the TFA method can help to provide information about the distribution of ester‐linked fatty acids and free fatty acids or fatty acid salts in soils and sediments.