Analysis of Some Pesticide Residues in Cauliflower by High Performance Liquid Chromatography

Problem statement: Increased use of chemicals on vegetables started gaining momentum and continued its up-trend in Bangladesh. Wide spread use of pesticides in agriculture concern of residue accumulation, which may remain in food and agricultural environment causing concern of human health and risking ecological balance. Attempt made to ensure that their applications were correct and safe and result in no residues in food beyond codex developed maximum residue limits. Approach: This study reported a method based on High Performance Liquid Chromatography (HPLC) for determination of pesticide residues used in Cauliflower. Cauliflower sprayed with, 4 different pesticides (diazinon, malathion, chlorpyrifos and cypermethrin) at recommended dose and double of recommended dose were analyzed for their residual contents. Samples were collected at same day after application of pesticide. Commercial samples of cauliflowers were collected from different markets of Dhaka city. Reversed-phase HPLC system with UV detection was used for the separation, identification and quantification of all these analytes using acetonitrile-water (70:30, v/v) as mobile phase. Results: Limit of detection of 0.02 mg kg^-1 was obtained. Calibration curves that constructed for the analytes spiked into samples followed linear relationships with good correlation coefficients (R²>0.990). In the analysis, from vegetables treated with diazinon and chlorpyrifos at recommended and double of recommended doses, residual amounts above respective MRL values were found. Conclusion: Method used permitted the determination of these pesticides in cauliflower at concentration level demanded by current legislation. Attention paid on excess use or abuse of pesticides by judicious application for safety of public health in Bangladesh. Additional data to monitor residues in food and to fill gaps in current knowledge would be helpful in assessing human exposure risks from ingestion of contaminated cauliflower or other vegetables.