Rapid analysis of polychlorinated biphenyls in fish by pressurised liquid extraction with in-cell cleanup and GC-MS

Abstract

An improved, rapid method for polychlorobiphenyl (PCB) extraction from lipid rich matrices and determination by GC-MS is presented. PCBs accumulate in the environment, can be extremely persistent, and health complications including neurotoxic effects have been reported. Thus, monitoring these persistent organic pollutants seems prudent. The analytical procedure for PCB assessment from environmental samples typically consists of the three steps extraction, purification and analysis by GC coupled with electron-capture detection or mass spectrometry. The aim of the present study was the implementation of a protocol allowing for determining selected indicator PCBs (n = 6) following a single extraction/purification step. Pressurised liquid extraction (PLE) combined with different silica layers directly in the extraction cell allowed efficient removal of lipids and direct analysis by GC-MS. Accuracy was determined by comparison with a reference standard (SRM 1946), and the equivalence of PLE to an established extraction method (soxhlet) was verified. Mean recovery of the combined procedure from trout spiked with a mixture of 50 ng of each PCB was 87 ± 8 (range 74–94)%, and results of ASE were comparable to soxhlet (difference total PCBs <16%). In addition, the protocol showed higher throughput (20 min/extraction cycle) and required less organic solvents (90 mL/sample). This method was then applied for monitoring PCBs in a variety of Luxembourgish fresh water fish (trout, eels, roaches, n = 38). The PCB profile was dominated by congeners 153 and 138, with maximum concentrations of 30 and 21 ng g−1 trout (fresh weight), respectively, highlighting that PCB concentrations might vary considerably in fish depending on species, eating habits and weight.