Sequential injection analysis for the determination of fuberidazole and thiabendazole by variable-angle scanning fluorescence spectrometry

A study of the behaviour of fuberidazole (FBZ) (2-(2'-furyl)benzimidazole), and thiabendazole (TBZ) (2-(thiazol-4-yl)benzimidazoie) in a sequential injection system with a fluorimetric detector has been performed. Several variables such as pH, composition of buffers, volumes of sample and reagents, addition order, geometry of mixing coil and spectrofluorimetric parameters have been optimised. A pH 2 buffer solution was found to be optimal for both FBZ and TBZ. The calibration graphs are linear between 0.04 and 10 mug l(-1) for FBZ and between 0.08 and 20 mug l(-1) for TBZ with 3 sigma detection limits of 0.012 and 0.02 mug l(-1), respectively. The relative standard deviation (n = 10) was 0.3% for 1 mug l(-1) of FBZ and 0.5% for 2 mug l(-1) of TBZ. Resolution of the system was carried out by applying a multiple linear regression (MLR) calibration model. The method was applied to the determination of both fungicides added to natural waters. Recoveries between 96 and 106% were achieved. (C) 2001 Elsevier Science B.V. All rights reserved.