Online Analysis of Volatile and Semivolatile Organic Compounds in Water Matrices Using a Dual-Channel Comprehensive Two-Dimensional Gas Chromatography Coupled with Time-of-Flight Mass Spectrometry System

Abstract

Monitoring organic compounds in aquatic matrices can be a complex and time-consuming process. To address this issue, we present a novel approach that uses a dual-channel comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS) system equipped with an automatic pretreatment platform for online monitoring of volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) in water matrices. Our automatic pretreatment platform incorporates headspace sampling (HS) and liquid–liquid extraction (LLE) to extract VOCs and SVOCs from water matrices. The GC × GC–TOFMS system features a dual-channel analytical structure column configuration, allowing for the sequential analysis of VOCs in the GC–TOFMS mode and SVOCs in the GC × GC–TOFMS mode. We quantitatively detected 55 and 104 target VOCs and SVOCs, respectively, in a water sample using the instrument system. Our method demonstrated excellent correlation coefficients ranging from 0.990 to 1.000, method detection limit ranging from 0.08 to 4.78 μg·L−1, relative standard deviation below 19.3%, and recovery rates ranging from 50.0% to 124.0%. To validate the online monitoring capabilities of our system, we tested the target SVOCs at three different concentration levels over a 3-day period. Most compounds exhibited recovery rates ranging from 70.0% to 130.0%. Furthermore, we applied our method to analyze a real water sample and successfully detected more than 100 target and nontarget VOCs/SVOCs, including alcohols, aldehydes, ketones, acids, esters, and phenols. Our results indicated the potential of our novel instrument system for effective screening and analysis of organic contaminants in aquatic matrices. This innovation provides a promising solution for improving the efficiency and accuracy of organic compound monitoring in water matrices.

Keywords: Comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry, Online water sample pretreatment platform, Dual-channel detection of both VOCs and SVOCs