Solid-phase extraction in combination with GC/MS for the quantification of free fatty acids in adipocere

Abstract

Current research investigating the effect of specific aquatic microenvironments on the formation of adipocere using domesticated pigs (Sus scrofa) has demonstrated the need for a fast and reliable method to separate and identify fatty acids present in adipocere. Adipocere is defined as a late-stage post-mortem decomposition product consisting of a mixture of free fatty acids (FPA), which have formed under favorable conditions due to the hydrolysis of triglycerides in adipose tissue. Whilst good separations of adipocere lipids have been achieved using TLC, this method is time consuming when processing large numbers of samples. This paper describes a rapid and simple method for the extraction, identification and quantification of FFA commonly found in adipocere, by solid-phase extraction (SPE) using aminopropyl disposable columns in combination with GC/MS. The recoveries of FFA associated with adipocere were all above 90%, with coefficients of variation below 10%, indicating that the technique was reproducible. The limits of quantification were registered at levels of parts per million. Standard curves were linear over the range of 50-1000 μg/mL, with all correlation coefficient values greater than 0.998. A marked increase in concentration of saturated fatty acids was observed during adipocere formation, ranging from 20 to 55% for palmitic acid, 13 to 23% for stearic acid and 2.8 to 4.1% for myristic acid. These results demonstrate the suitability of aminopropyl disposable SPE columns to efficiently and rapidly isolate FFA from adipocere prior to quantitative GC/MS analysis. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim