Simultaneous Determination of Dimethomorph and Chlorothalonil in Pesticide Formulation: HPLC Method Development and Validation

Abstract

The identification and accurate quantification of pesticides is important to verify the recommended
concentration of active content of each pesticide in formulated products to avoid adverse effects on human life due to
over dosage. In this study, method of quantitative determination of Dimethomorph and Chlorothalonil in pesticide
formulation was developed and validated by using ICH guidelines. Chromatographic separations with good resolution
were performed on Beckman C-18 column (5 µm x 150 mm x 4.6 mm), using 80:20, v/v – (CH3CN:H2O) as mobile
phase in isocratic mode at 230 nm. The retention time for Dimethomorph and Chlorothalonil at flow rate 1.2 mL/min
was 6.21 and 9.63 minutes, respectively. Calibration curves of both studied fungicides (Chlorothalonil and
Dimethomorph) were linear showing coefficient of determination greater than 0.996. %RSD value of inter-day
precision was found to be less than 3 for both pesticides and for intra-day precision these values were less than 2. Inter
laboratory comparison (ILC) method was applied to evaluate the accuracy of the proposed method and Z-score values
were found to be less than 2. The proposed method is therefore efficient, accurate, and cost-effective and can suitably
be used for simultaneous quantitative determination of Dimethomorph and Chlorothalonil in pesticide formulated
products.