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 ¼ 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 AE 8 (range 74-94)%, and results of ASE were comparable to soxhlet (difference total PCBs 516%). 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 ¼ 38). The PCB profile was dominated by congeners 153 and 138, with maximum concentrations of 30 and 21 ng g À1 trout (fresh weight), respectively, highlighting that PCB concentrations might vary considerably in fish depending on species, eating habits and weight.

Recent development in analysis of persistent organic pollutants under the Stockholm Convention

“…PLE is becoming more popular because it can be highly automated and unattended extractions can be performed overnight to improve sample throughput. In addition to that, many authors [9,10,25,26,28,33,42,47,48] attempted in-cell clean-up by packing different absorbents and copper with samples inside the cell for simultaneous extraction and clean-up with good analyte recovery and precision.…”

“…So far, routine procedures {e.g., sulfuric-acid treatment [15,21] and gel-permeation chromatography [10]}, and multi-column separation using acidified and/ or alkalinized silica, alumina, and Florisil, silver-nitrateimpregnated silica absorbents [8,[12][13][14][15][16][20][21][22][23]60] are being widely adopted and becoming absolutely necessary. Some authors [9,11,25,26,28,33,42,47] combined extraction and clean-up in one run and substantially reduced the solvent used and time required for sample preparation.…”

Distribution and Health Risk Assessment of Selected Endocrine Disrupting Chemicals in Two Fish Species Obtained from Choba River in Rivers State, Nigeria

“…Shaogang et al [25] reported a total PCB level of 0.864µg/g for fish samples analyzed in China which was found to be higher than the concentration obtained in this study. Also, a total PCB concentration of 0.094 µg/g for fish sample (trout) caught in Luxembourg was reported by Cocco et al [26].…”

Estimation of daily intake of polychlorinated biphenyls not similar to dioxins (NDL-PCB) from fish consumption in Spain in different population groups

“…The final extract of the sample was evaporated to dryness under a stream of nitrogen, reconstituted by the addition of 0·5 ml hexane and then transferred to two vials with a 250 μl insert for determination by GC–MS/MS. The detection by GC–MS/MS was performed in a gas chromatograph coupled to a triple-quadrupole mass detector (TSQ Quantum™, ThermoFisher Scientific) equipped with a DB-XLB column (30 m length, 0·250 mm diameter, 0·50 μm film thickness) ( 24 , 25 ) .…”