Contents of fatty acids in surface sediment samples from the northwestern South China Sea

The method used for extraction, purification, and isolation of n-fatty acids were similar to those described by Mollenhauer and Eglinton (2007). About 70–140 g samples and an aliquot of ~3 g of each sample (for quantification) were Soxhlet extracted with DCM: MeOH (9:1, v/v). After saponification, the neutral lipids were recovered with n-hexane and the remaining solution was acidified to pH 1, from which FAs were extracted into DCM. The extracted FAs were converted to methyl ester derivatives (FAMEs) and contents were measured by an Agilent 7890A gas chromatograph (GC) equipped with a DB-5MS capillary column (60 m, 250 µm, 0.25 µm) and a flame ionization detector (FID).