Sensitive Methodology for Simultaneous Determination of Residues of Imidacloprid and its Metabolites in Sugarcane Leaves and Soil

An analytical method to quantify imidacloprid and its metabolites in sugarcane leaves and soil using HPLC has been developed. The samples were extracted with acetonitrile + water (80 + 20, v/v), soil samples partitioned with dichloromethane, and leaf samples with hexane + ethyl acetate (9 + 1, v/v) and dichloromethane. Further, the extracts were dried, filtered, and concentrated under vacuum into HPLC-grade acetonitrile. Residues were estimated using an HPLC equipped with a photodiode array detector system, C-18 column with a mobile phase of acetonitrile + water (40 + 60, v/v) at 0.3 mL/min to separate imidacloprid and its six metabolites in single run of 20 min. The mean percent recoveries of imidacloprid and its metabolites ranged from 80.45 to 99.80 from sugarcane leaves and 80.20 to 99.70 from sugarcane soils. The analytical method was validated in terms of selectivity, linearity, reproducibility, repeatability, and accuracy. The repeatability values ranged from 0.24 to 3.15% and 1.69 to 4.94%, along with 2.73 to 3.82% and 1.12 to 4.96%, for imidacloprid and its metabolites in leaves and soil, respectively. The reproducibility of imidacloprid and its metabolites in leaves and soil ranged from 2.20 to 4.27% and 2.53 to 4.08%, respectively, and all measurements were within 15% at all concentration levels.