Determination of 20 Polybrominated Diphenyls and Polybrominated Diphenyl Ethers in Polystyrene Casings of Electrical Appliances by Pyrolysis-Gas Chromatography-Mass Spectrometry

The sample of polystyrene casing was pretreated by machining to pass through sieve with 1 mm mesh, and 0.5 mg of the fine sample particles was taken and pyrolyzed in a pyrolyzer at 340℃ for 60 s by raising the temperature from the initial value of 100℃ at a rate of 20℃·min^-1, to liberate the 20 polybromo compounds (PBBs and PBDEs) from the polystyrene sample. The PBBs and PBDEs were introduced instantly into DB-1 chromatographic column and separated under the condition of split-flow sample introduction and programed temperature elevation with helium gas as carrier, and then determined by MS with EI ionic source and under SIM mode. Linear relationships between values of mass fractions and peak areas of the 20 compounds were found in the same range of 100-2 000 mg·kg^-1. Detection limits (3S/N) found for these analytes were all less than 15 mg·kg^-1. Tests for recovery were made by addition of mixed standard solution at 3 concentration levels, giving values of recovery ranged from 77.9%-119%. Values of RSDs (n=7) found were all less than 20%. Three substantial samples were analyzed by this method and checked by the standard method (appendix A of GB/T 26125-2011). Consistent results were found for the two methods.