Development of workflows for non-target screening and structure elucidation of environmental contaminants

Chemische Analyse

One of the major bottlenecks in effect-directed analysis and non-target screening is the elucidation of unknown structures of candidate toxicants in environmental samples and fractions thereof. In classical chemistry, structures are positively elucidated with nuclear magnetic resonance spectroscopy (NMR). NMR requires compound amounts and purities which are typically not available from environmental samples. Thus, we develop multi-lines-of-evidence approaches exploiting as much information as possible available from chemical analysis and biotesting for structure elucidation of environmental chemicals. We use this information together with models predicting toxicity and compound behavior in chromatography and mass spectrometry in order to exclude candidate structures with misfits between observation and prediction. Major tools which are developed advanced and integrated in analytical workflows, e.g. in the European ITN EDA-EMERGE, include

• state-of-the-art analysis using LC-MS/MS (AB SCIEX, QTRAP6500), LC-HRMS/MS (Thermo LTQ Orbitrap XL) and GC-MS/MS (Agilent 7000 Triple Quad)
• computer tools for peak picking and establishment of molecular formulas
• prediction tools for chromatographic retention and MS fragmentation
• toxicity prediction to focus on candidates with potential effects
• the establishment of a comprehensive database MassBank (link) for mass spectra (particularly LC-HRMS/MS) of environmental pollutants