Chiang Mai Journal of Science

     The contamination of Thai agricultural products by chemical insecticides such as carbofuran, carbaryl, and methomyl poses significant threats to food safety, public health, and consumer confidence. To address this issue, an effective detection method for these carbamate insecticides in fruits and vegetables using QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction, followed by a high-performance liquid chromatograph-diode array detector (HPLC-DAD), was developed. Key parameters including extraction salt type, solvent mixture ratio between acetonitrile and water, and mobile phase flow rate were systematically optimized. The optimized chromatographic conditions consisted of an acetonitrile-water mixture (50:50, v/v) with a flow rate of 1.75 mL min⁻¹. Importantly, complete chromatographic separation was achieved within 3 minutes, markedly reducing the analysis time compared with conventional HPLC methods. Under these optimal conditions, excellent linear correlations were obtained between peak area and analyte concentration for carbofuran, carbaryl, and methomyl within the ranges of 100–1,000, 50–1,000, and 50–1,000 µg L⁻¹, respectively, with corresponding limits of detection of 51.11, 11.31, and 11.80 µg L⁻¹. The method demonstrated high precision with a relative standard deviation percentage <10%, and satisfactory recoveries between 68.45%–109.57%. Moreover, sodium sulfate (Na₂SO₄) was introduced as a cost-effective and environmentally friendly QuEChERS salt, providing high-resolution separation suitable for Thai agricultural matrices. This method offers a rapid, reliable, and sustainable approach for routine surveillance of carbamate insecticide residues in agricultural commodities in regional laboratories, supporting national food safety monitoring and regulatory compliance.