Detecting trace levels of contaminants in water samples requires an optimized set of methods for sample preparation, liquid chromatography (LC), and mass spectrometry (MS). For advice about these methods, LCGC talked to Damià Barceló, a leading researcher in water and environmental analysis. Barceló is a research professor with the Scientific Research Council (CSIC) of the government of Spain, at the Institute of Environmental Assessment and Water Research (IDAEA) in Barcelona. He is also the director of the Catalan Institute for Water Research (ICRA) in Girona. He has published more than 775 peer-reviewed papers on water and environmental research.