Simultaneous determination of fenamiphos, its sulphoxide and sulphone in water by high-performance liquid chromatography.

A method for the simultaneous determination of fenamiphos and its two metabolites, fenamiphos sulphoxide and fenamiphos sulphone, in water is described. The proposed method is based on the separation of the compounds on a silica gel column with ultraviolet detection and overcomes the problems of inadequate separation and possible decomposition associated with the gas-chromatographic determination of these compounds. The application of the method to groundwaters showed that a minimum detection level of the order of 10 micrograms l-1 could be achieved easily with pre-concentration of the samples on Sep-Pak C18 disposable cartridges.