Determination of Mancozeb and Maneb using flow injection chemiluminescence detection

Abstract

A rapid flow injection chemiluminescence method is developed to determine mancozeb and maneb fungicides in natural water samples in the range 0.0025–0.25 ppm (R2 = 0.9996, n = 6) and 0.01–0.75 ppm (R2 = 0.9994, n = 6) with limit of detections of 0.001 and 0.005 ppm (S/N = 3), relative standard deviations of 1.75% and 1.8% and 200 h–1injection throughputs, respectively. The method is based on diperiodatonickelate(IV)-rhodamine 6-G-Brij-35 chemilu-minescence reaction in potassium hydroxide medium enhanced by mancozeb and maneb. Several other oxidising agents instead of diperiodatonickelate(IV) are checked and diperiodatoargentate(III) enhanced appreciably the emission chemiluminescence intensity. Mancozeb and maneb are extracted from water samples by solid-phase extraction technique with the calculated recoveries in the range of 92–108% and relative standard deviations of 1.41–2.67%. The probable chemiluminescence mechanism is proposed with the help of UV-Vis spectrophotometric and CL studies.