Development and optimization of gas chromatography coupled to high resolution mass spectrometry based method for the sensitive determination of Dechlorane plus and related norbornene-based flame retardants in food of animal origin

An analytical method has been developed for the trace determination of 10 dechlorane-related compounds (DRCs) in food products by gas chromatography - high resolution mass spectrometry (GC-HRMS). The highest sensitivity of this instrumental analysis method was achieved by selection of the GC column type, optimization of the heated zones within the instrument, and adjusting the electron impact energy. The efficiency of solid phase extraction as clean-up procedure was also optimized. Two different types of cartridges - neutral silica gel and Florisil^®, as well as seven organic solvents or their mixtures - n-hexane, cyclohexane, acetone, toluene, n-hexane/ethyl acetate, n-hexane/acetone, and n-hexane/dichloromethane - were evaluated. The analytical method was characterized as selective, precise, accurate, and linear over the concentration ranges from 1.00 to 100 pg μL^-1 for DRCs. Ultra-trace level sensitivity was achieved with the instrumental limits of quantification (i-LOQs) varying from ∼0.01 pg to ∼ 1 pg and method limits of quantification (m-LOQs) by the analysis of 10 g of sample varying from ∼0.04 to ∼ 5 pg g^-1. The developed method was successfully applied for the analysis of food samples and the analyses revealed the presence of majority of selected DRCs, with the Dechlorane Plus (DP) isomers occurring to a greater extent, pointing to the highest levels in cod liver and other fish products.

The occurrence of Dechlorane Plus and related norbornene-based flame retardants in Baltic wild salmon (Salmo salar)

Twenty five Baltic wild salmon (Salmo salar) specimens were analysed for the content of Dechlorane-related compounds (DRCs). Out of the ten analysed DRCs, seven compounds were detected in the muscle tissues of salmon, including Dechlorane (Dec) 602, Dec 603, syn- and anti-stereoisomers of Dechlorane Plus (DP), Dechlorane Plus monoadduct (1,3-DPMA), hexachlorocyclopentadienyl-dibromocyclooctane (DBHCTD), and Mirex. The concentrations of Dec 604 and two DP dechlorinated compounds - decachloropentacyclooctadecadiene (Cl10DP) and undecachloropentacyclooctadecadiene (Cl11DP) - were below the limit of detection in all samples. The aggregated concentrations of DRCs (ΣDRC) were in the range of 551-3339 pg g(-1) fresh weight (f.w.) with 1,3-DPMA being the predominant DRC component contributing up to 70% to the ΣDRC. The fractional abundance of syn- and anti-DP stereoisomers showed a pronounced enrichment of anti-DP and was close to the composition of OxyChem(®) DP commercial product. The obtained concentrations of DRCs were substantially lower than those reported in previous studies of biotic samples (among them fish, mollusks, white stork and peregrine falcon eggs) from inland freshwater reservoirs in more industrialised areas throughout Europe and North America. A statistically significant relationships between the concentrations of Dec 602 and the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) was observed.