Advanced GC–MS and LC–MS Tools for Structure Elucidation in Effect-Directed Analysis

Abstract

An important step in effect-directed analysis (EDA) is the identification of the compound(s) causing the biological response of the bioassay. The combined use of gas chromatography (GC) and liquid chromatography (LC) with mass spectrometry (MS) is a powerful, complementary approach for identification of unknown compounds in EDA. In the last decade, MS techniques have evolved considerably with respect to high sensitivity scanning and non-target screening. These new techniques, often with high mass resolution, generate large amounts of data, making the evaluation of the data for further prioritization and selection of the peaks of interest a challenging task. The development of LC–MS strategies for structure elucidation of unknown compounds requires a major effort, as current LC–MS libraries are very limited. Comprehensive two-dimensional GC (GC × GC) coupled to low-resolution rapid-scanning MS is an established technology for the separation and identification of compounds in complex mixtures. However, to enable the empirical formula assignment of unknown compounds, it is required that GC × GC is combined with rapid-scanning accurate mass spectrometers.