Multiresidue analysis of pesticides in three Indian soils: method development and validation using gas chromatography tandem mass spectrometry

The paper reports a multiresidue method that was validated on 220 multi-class pesticides in three major Indian soils, namely, (i) new alluvial soil (NAS); (ii) red lateritic soil (RS) and (iii) black soil (BS) from three different regions. An ethyl acetate-based extraction method with a freezing-out cleanup step was employed for sample preparation, followed by gas chromatography-tandem mass spectrometric analysis. The method that was initially optimized on BS worked satisfactorily for the other two soil matrices. At the spiking level of 10 mu g/kg (LOQ), the recoveries were satisfactory (within 70-120%) with precision-RSDs, <= 20% (n = 6) for 85, 88.6, and 89% of compounds in BS, RS, and NAS respectively. At 20 mu g/kg, the method performance was satisfactory in each soil for all pesticides. When this validated method was applied to analyse 25 field samples, 6 pesticides were detected in them. In each case, precision (RSD) was <20%. The method sensitivity, accuracy and precision complied with the SANTE/2020/12830 guidelines. The method can be applied for environmental monitoring and risk assessment purposes, thus aiding in regulating pesticide usage in agricultural fields. The limitations and future scope of the study are also discussed.