Selective and comprehensive analysis of organohalogen compounds by GC × GC–HRTofMS and MS/MS

Thousands of organohalogen compounds, including hazardous chemicals such as polychlorinated biphenyls (PCBs) and other persistent organic pollutants(POPs), were selectively and simultaneously detected and identified with simple, or no, purification from environmental sample extracts by using several advanced methods. The methods used were software extraction from two-dimensional gaschromatography–high-resolution time-of-flight mass spectrometry (GC × GC–HRTofMS) data, measurement by negative chemical ionizationwith HRTofMS, and neutral loss scanning (NLS) with GC × GC–MS/MS. Global and selective detection of organochlorines and bromines in environmental samples such as sediments and fly ash was achieved by NLS using GC × GC–MS/MS (QQQ), with the expected lossesof 35Cl and 79Br. We confirmed that negative chemical ionizationwas effective for sensitive and selective ionization of organohalogens, even using GC × GC–HRTofMS. The 2D total ion chromatograms obtained by using negative chemical ionizationand selective extraction of organohalogens using original software from data measured by electron impact ionizationwere very similar; the software thus functioned well to extract organohalogens. Combining measurements made by using these different methods will help to detect organohalogens selectively and globally. However, to compare the data obtained by individual measurements, the retention times of the peaks on the 2D chromatograms need to match.