抄録
Methyl (MCF) and ethyl chloroformate (ECF) derivatizations are potentially useful for rapid and simple esterification (i.e., at room temperature for 5 min) prior to compound-specific stable isotope analysis (CSIA) of fatty acids. In this study, we have used acetonitrile as an organic solvent in the esterification process to improve the yields of derivatives, and we evaluated whether the improved esterification is suitable for carbon and hydrogen CSIA. Six saturated (14:0, 16:0, 18:0, 20:0, 22:0, and 24:0) and three unsaturated (18:1 n-9, 18:2 n-6, and 18:3 n-3) fatty acids were used in this study. The yields of derivatives are 67-107% for MCF and 84-89% for ECF derivatizations, which are approximately twice the yields obtained in MCF and ECF derivatizations that did not use acetonitrile. The accuracy of the CSIA is <±0.4‰ (1σ) for carbon and <± 11‰ (1σ) for hydrogen, with no significant differences in these uncertainties observed for saturated and unsaturated fatty acids. Thus, MCF and ECF derivatizations using acetonitrile are suitable for the CSIA of fatty acids.
