Determination of Chlorinated/Brominated Flame Retardants and their Metabolites in Breast Milk
A method was developed for the determination of trace-amount chlorinated/brominated flame retardants and their metabolites in breast milk by gas chromatography combined with mass spectrum in negative chemical ionization mode(GC/NCI-LRMS).Chlorinated/brominated flame retardants and their metabolites were classified into netural and phenolic fractions.Neutral targets included eight brominated diphenyl ether(BDE) congeners(including BDE-209),five MeO-BDE congeners and other new flame retardants or the metabolites.Phenolic targets referred to nine OH-BDEs congeners.The efficient separation of various neutral targets was obtained on a 30-m column(RTX-1614) and that of phenolic targets was achieved on a 30-m column(DB-5) in the optimized GC condition.In the extraction and clean-up procedures,before supersonic extracting,surrogate/internal standards were required spiking into breast milk,then the samples were separated into neutral and phenolic fractions by a liquid-liquid extraction methods.The extracts were cleaned-up further to remove other co-extracts by sulfuric acid silica prior to injection.It was noticeable that phenolic fractions required to be further derived by diazomethane before clean-up.The recoveries of decabrominated diphenyl ethers,other polybrominated diphenyl ethers,methoxyl-polybrominated diphenyl ethers,dechlorane plus and dechlorinated products,other flame retardants,hydroxylated polybrominated diphenyl ethers were 66.5%-75.4%,84.2%-126.4%,60.9%-115.1%,86.7%-104.9%,42.9%-113.8% and 64.7%-129.5%,respectively.The RSD of neutral targets were all below 22%,and those of the phenolic targets were all below 30%.The method was used for the determination of targets in breast milk collected from an e-waste dismantling area.The results of quality control showed the method was reliable investigation.