Abstract
An easy and simple analytical method was standardized and validated for the estimation of residues of spirotetramat and its metabolite spirotetramat cis enol in various substrates: okra fruits, brinjal leaves and fruits, green chili, red chili, and soil. The samples were extracted with acetonitrile, diluted with brine solution, partitioned into dichloromethane, dried over anhydrous sodium sulfate, and cleaned up by treatment with activated charcoal powder. Final clear extracts were concentrated under vacuum and reconstituted with HPLC grade acetonitrile. Residues were estimated using HPLC with a photodiode array detector and a C18 column, and confirmed by HPTLC. Acetonitrile was used as the mobile phase at 0.4 mL/min. Both spirotetramat and spirotetramat cis enol presented distinct peak at retention times of 8.518 and 7.598 min, respectively. Consistent recoveries ranging from 82 to 97% for spirotetramat and spirotetramat cis enol were observed when samples were spiked at 1.00 to 0.03 mg/kg levels. The LOQ of the method was found to be 0.03 mg/kg. The analytical method was validated in terms of parameters, including selectivity, linearity, precision, and accuracy.
