An efficient clean-up method for the GC–MS determination of methylsulfonyl-PCBs/DDEs extracted from various marine mammal tissues

Existing methods for analyzing methylsulfonyl-PCBs in animal tissues require multiple laborious clean-up steps prior to quantitation. In this paper, we report a new, efficient method for the isolation and determination of methylsulfonyl-PCB metabolites in the blubber, liver, kidney, lung, and milk from mammals of marine origin using: solvent extraction, GPC fractionation, and clean-up on an adsorption chromatography column prior to analysis by gas chromatography–mass spectrometry. The method is rapid and can be completed in about half the analysis time required by most other reported methods. The method exhibits excellent analyte recoveries (89–95%), and good reproducibilities with CVʹs ranging from 3–12% depending on analyte concentration. Detection limits are approximately 1 ng/g lipid. The method is further validated by comparing its quantitative results to that of an independent reference analytical method for several different marine mammal blubber samples. Finally, the method is applied to profile the distribution of methylsulfones among the various tissue types studied for a single bottle-nose dolphin (Tursiops truncatus) sample. In addition, the extent of their transplacental transfer from mother to unborn fetus for several pilot whale (Globicephala melaena) mother-fetus pairs is examined.