Multiresidue Analysis of Pesticides in Three Indian Soils: Method Development and Validation Using Gas Chromatography Tandem Mass Spectrometry

Abstract The paper aimed to develop an effective multiresidue extraction method in three major soil types, namely i) new alluvial soil (NAS); ii) red lateritic soil (RS) and iii) black soil (BS) in the Indian subcontinent for determining the residues of pesticides from various chemical classes. To establish an effective pre-treatment process, an ethyl acetate-based extraction method with a freezing out cleanup step was employed. The analysis was performed using gas chromatography-tandem mass spectrometry (GC-MS/MS). The validation experiments were performed on 220 GC-amenable pesticides by spiking all soil samples. The linearity of the calibration curves was satisfactory in matrix-matched standards and yielded the coefficients of determination (R2) ≥0.99 for approximately 98% of the target analytes in all matrices. At 10 ng/g, the recoveries of the spiked pesticides were in the range of 70–120%, with associated precision-RSD values ≤20% for approximately 85%, 88.6% and 89% of the compounds for BS, RS and NAS respectively. At the higher spiking levels of 20 and 50 ng/g, average recoveries and RSDs readily met the validation criteria of all the studied pesticides. Overall, the method holds potential as a suitable procedure for multiresidue analysis in soils for safety evaluation and risk assessment purposes.