Photochemically-induced fluorescence determination of sulfonylurea herbicides using micellar media

An analytical method based on the use of UV irradiation to produce fluoresc ent derivatives from four non-fluorescent sulfonylurea herbicides, includin g chlorsulfuron, metsulfuron methyl, 3-rimsulfuron and sulfometuron methyl is described. Their photochemically-induced fluorescence (PIF) properties i n several solvents (water, dimethyl sulfoxide (DMSO), dimethyl formamide (D MF), acetonitrile, methanol, ethanol, propan-2-ol and their binary mixtures with water) and micellar solutions of sodium dodecyl sulfate (SDS), and ce tyltrimethylammonium chloride (CTAC) are reported. Physicochemical variable influencing the sensitivity of the method have been optimized. A PIF metho d is developed for the determination of the four herbicides under study. Mi cellar media are found to provide the best analytical figures of merits. Li near dynamic ranges are established over about two orders of magnitude. The limit of detection (LOD) range from 0.2 to 6 ng ml(-1) according to the co mpound, with relative standard deviation (RSD) between 1.2 and 3.9%. Exampl es of applications to the analysis of these herbicides in spiked river wate r samples are given. The mean recoveries range from 80 to 104%. (C) 1999 El sevier Science B.V. All rights reserved.