Dual chromatographic analysis of pesticide residues in eggplants: a green approach to food safety monitoring

The determination of pesticide residues is crucial for safeguarding human health, ensuring food safety, and contributing to environmental sustainability. Chlorfenapyr (CLF), abamectin (ABM), and fenpyroximate (FNP) are widely employed in eggplant (Solanum melongena L.) cultivation for pest control. This study presents the first reported simultaneous analysis of these pesticides using two validated chromatographic methods: high-performance thin-layer chromatography (HP-TLC, Method A) and reversed-phase high-performance liquid chromatography (RP-HPLC, Method B). Method A employed a mobile phase of methanol/chloroform/glacial acetic acid/triethylamine (7.00:2.50:0.50:0.10, v/v) with densitometric UV detection at 225 nm. The retention factors (Rf) for CLF, ABM, and FNP were 0.13, 0.34, and 0.85, respectively. Method B utilized a mobile phase of acetonitrile/5 mM ammonium acetate buffer (pH 4.0) (70:30, v/v) at a flow rate of 1.20 mL/min, with UV detection at 255 nm. The retention times for CLF, ABM, and FNP were 3.4, 6.1, and 8.4 min, respectively. Both methods were validated according to the key principles of ICH guideline Q2(R2) for the validation of analytical procedures, demonstrating robustness for assaying the ternary pesticide mixture in pure forms, commercial formulations (with excipients), and spiked eggplant samples. Both developed methods exhibited excellent detection and quantification capabilities. Method A demonstrated LODs ranging from 0.0006 to 0.0027 µg/band and LOQs from 0.0019 to 0.009 µg/band. Method B achieved even lower detection limits, with LODs from 0.0029 to 0.0296 µg/mL and corresponding LOQs from 0.0089 to 0.089 µg/mL for the target pesticides.