Browsing by Author "Munjanja, Basil K."

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    Occurrence of pesticides used in tobacco farming in edible vegetables and environmental samples
    (2013-09) Munjanja, Basil K.; Madzivire-Penduka, Cecilia; Sanganyado, Edmond
    A method was developed and validated for the analysis of chlorothalonil (CT), dimethoate (DM) and triadimenol (TD) in soil, surface water and edible green vegetables. In method development, A range of solvents were evaluated, and ethyl acetate was observed to be the best extracting solvent in soil and vegetable samples, while acetonitrile was the best extracting solvent in water samples. The effect of solvent type, solvent volume and extraction time on recovery of pesticides was studied. Analysis was carried on HPLC-UV a C18 column using a mobile phase comprising CH3CN/water (50:50, v/v) with a flow rate of 1.0ml/min in isocratic mode. The pesticides were extracted by ultrasonication and obtained recoveries in water, soil and vegetables ranged from 65-91 %. Furthermore, the detection limit in water, soil and vegetables was 0.01 µg/L, 2.8 µg/kg and 0.005 µg/kg, respectively. Limits of quantification ranged from 0.25-1.25µg/kg for vegetables, 1.35-2.3µg/kg and 0.02-0.05µg/l. Precision was measured in terms of the RSD, and values were less than 10%. The method was successfully applied to the analysis of incurred vegetable, soil and water samples from 3 farms from Bromley A2 agricultural area near Marondera, Zimbabwe. About 1.6µg/kg of CT was detected at one farm in soil samples, DM (0.025µg/l) was detected at another farm in well water. However, TD was not detected in all samples and no pesticides were detected in vegetable samples.