Analytical Method Validation for the Determination of Meptyldinocap As 2,4-Dinitrooctylphenol Metabolite in Mango and Soil Using LC-MS/MS and Dissipation Study of the Fungicide in Indian Mango Field Ecosystem

摘要

An analytical method for the quantitative determination of meptyldinocap (2,4-DNOPC) as 2,4-dinitrooctylphenyl (2,4-DNOP) in mango and soil was developed as well as validated using liquid chromatography tandem mass spectrometry (LC-MS/MS). The method comprised an extraction with an acetone:methanol:4 N HCI (100:10:5, v/v/v) mixture followed by hydrolytic conversion of parent 2,4-DNOPC to the corresponding phenol metabolite (2,4-DNOP), and cleanup was done by liquid:liquid partition using ethyl acetate. Final quantitation was performed by LC-MS/MS of 2,4-DNOP with negative electrospray ionization using gradient elution. The method wasvalidated at concentrations ranging from 0.025 to 2 μg/g, and the limit of quantification (LOQ) of meptyldinocap in mango and soil samples was 0.025 ftglg. The recovery of meptyldinocap from mango and soil sample was found to be 93-98% spiked at different levels with analyte, and the relative standard deviation for repeatability (RSD_r) and reproducibility (RSD_R) were acceptable (2-6%). The method was rugged as evident from a low measurement uncertainty at 0.05 μg/g. In order to evaluate its safety use in India a multilocational field dissipation study on meptyldinocap in mango was conducted by following the proposed analytical method.