A Novel Method for Profiling and Quantifying Short- and Medium-Chain Chlorinated Paraffins in Environmental Samples Using Comprehensive Two-Dimensional Gas Chromatography-Electron Capture Negative lonization High-Resolution Time-of-Flight Mass Spectrometry

摘要

Chlorinated paraffins (CPs) are complex technical mixtures containing thousands of isomers. Analyzing CPs in environmental matrices is extremely challenging. CPs have broad, unresolved profiles when analyzed by one-dimensional gas chromatography (GC). Comprehensive two-dimensional GC (GCxGC) can separate CPs with a high degree of orthogonality. A novel method for simultaneously profiling and quantifying short- and medium-chain CPs, using GCxGC coupled with electron capture negative ionization high-resolution time-of-flight mass spectrometry, was developed. The method allowed 48 CP formula congener groups to be analyzed highly selectively in one injection through accurate mass measurements of the [M - Cl]~- ions in full scan mode. The correlation coefficients (R~2) for the linear calibration curves for different chlorine contents were 0.982 for short-chain CPs and 0.945 for medium-chain CPs. The method was successfully used to determine CPs in sediment and fish samples. By using this method, with enhanced chromatographic separation and high mass resolution, interferences between CP congeners and other organohalogen compounds, such as toxaphene, are minimized. New compounds, with the formulas C_9H_(14)Cl_6 and C_9H_(13)Cl_7, were found in sediment and biological samples for the first time. The method was shown to be a powerful tool for the analysis of CPs in environmental samples.