Screening for petrochemical contamination in seafood by headspace solid-phase microextraction gas chromatography-mass spectrometry.

A headspace solid-phase microextraction gas chromatography-mass spectrometry (SPME GC-MS) method is described, to screen seafood for volatile organic compounds (VOCs) associated with petrochemical taint. VOCs are extracted from the headspace of heated sample homogenates by adsorption onto a SPME fiber and desorbed for analysis by GC-MS. Targeted compounds are determined semi-quantitatively using representative calibration standards for the various classes (alkanes, alkylbenzenes, indanes/tetralins, and naphthalenes) of VOCs analyzed. Sample preparation is minimal, and the analyses are rapid and automated with a capacity of 50 samples per day. The method was optimized in terms of headspace temperature, sample heating time, extraction time, and desorption time using oyster samples fortified with target compounds. Calibrations for hydrocarbon components were linear in the range of 8.3-167 ng/g; the limit of detection ranged between 0.05 and 0.21 ng/g, and the limit of quantitation between 0.16 and 0.69 ng/g. Good precision (RSD < 10 % at 16.7 ng/g for individual VOCs) and accuracy (recovery range 89-118 % at 25 ng/g) were obtained in oyster, crab, shrimp, and finfish matrices. The trueness of the method was demonstrated by quantifying VOCs at 1-2-ppb levels in oyster fortified with certified reference material NIST SRM 1491a. Following single laboratory validation, the method was employed for the determination of VOCs in seafood exposed to oil contaminated seawater and for the determination of background VOC levels in seafood species from the Gulf of Mexico and local food stores. The method as described can be used to supplement human sensory testing for petrochemical taint in seafood.