Accurate mass determinations for the confirmation and identification of organic microcontaminants in surface water using on-line solid-phase extraction liquid chromatography electrospray orthogonal-acceleration time-of-flight mass spectrometry

The identification of polar microcontaminants in surface water is an import ant issue in environmental analysis. Liquid chromatography/mass spectrometr y (LC/MS) is frequently applied for this purpose. However, even in combinat ion with tandem mass spectrometry (MS/MS), unambiguous identification of th e compounds detected is often difficult. The potential of an alternative st rategy, based on the ability of an orthogonal-acceleration time-of-flight m ass spectrometer to routinely perform accurate mass determination at 10 ppm in on-line LC/MS, is explored. On-line solid-phase extraction LC electrosp ray orthogonal acceleration time-of-flight mass spectrometry is shown to en able the determination of pesticides from various compound classes in surfa ce water in the concentration range of 0.1 to 10 mu g/L. In addition, the a bility to discriminate and unambiguously identify pesticides in mixtures of isobaric and/or isomeric compounds is investigated. Copyright (C) 1999 Joh n Wiley & Sons, Ltd.