Characterization of photodegradation products of alachlor in water by on-line solid-phase extraction liquid chromatography combined with tandem mass spectrometry and orthogonal-acceleration time-of-flight mass spectrometry

On-line solid-phase extraction liquid chromatography in combination with ma ss spectrometry (MS), i.e. MS/MS and orthogonal-acceleration time-of-flight MS, was used for the characterization of photodegradation products of alac hlor in river water, Various MS/MS scan functions were used, In particular the precursor-ion and the daughter-ion modes, to screen for degradation pro ducts with structures closely related to that of alachlor and to obtain inf ormation on characteristic fragments of the degradation products. Elemental compositions of compounds found and some of their fragments were calculate d from the accurate mass information obtained with orthogonal-acceleration time-of-flight MS. Some ten degradation products could be characterized by combining various types of mass spectral information. Since quite a number of isomers were identified, structures of the degradation products were pro posed by considering the most likely fragmentation patterns in MS/MS experi ments. Degradation products of alachlor found in the current study were com pared with those reported in the literature. Copyright (C) 2000 John Wiley & Sons, Ltd.