The compound-independent calibration of polybrominated diphenyl ethers isomers using gas chromatography-inductively coupled plasma mass spectrometry

Abstract

Compound-independent calibration (CIC) is a quantitative method that can quantify other compounds using a structure-independent compound as the calibrant. In this study, the potential and application of CIC method for the determination of polybrominated diphenyl ethers (PBDEs) using GC-ICP-MS was investigated. The effects of sample introduction conditions, the flow rate of the carrier gas, splitless delay time and the matrix of the complex sample on the response of 11 PBDEs compounds were explored. When pulsed splitless injection was used, the transmission efficiency of analytes from the inlet to the column can speed up with increasing injection temperature and pulse pressure, the elemental response of bromine of each analyte becomes closer. Under optimized chromatographic conditions, the response is independent of the compound can be found from the slope of the pure solution standard from tri- to hepta- brominated compounds (BDE 28 as reference) ranged from 0.968 to 1.001 (R2>0.998).The degradation ratio of BDE 209 in the GC-ICP/MS system was estimated by the CIC method to be 18.7%. During the determination of fish tissue sample, big difference of the elemental response ratio (BDE 28 as reference) was obtained range from 0.678 to 0.976. However, a similar elemental response was observed among isomers range from 0.990 to 1.056. This may mean that the isomers can be calibrated to each other in a complex matrix sample. The CIC method was validated by determination 3 PBDEs in NIST SRM 1947 frozen fish tissue certified reference materials using isomers as reference compounds. The recoveries of BDE 49 and BDE 66 were 105.7% and 88.1% by using BDE 47 as calibrants, and that of BDE 155 was 108.8% by using BDE 154 as calibrant.