Chiang Mai Journal of Science

     A dispersive micro-solid phase extraction (D-μ-SPE) has been investigated for simple microextraction and preconcentration of fi ve neonicotinoid insecticides residues followed by highperformance liquid chromatography. The neonicotinoid insecticides including thiamethoxam, clothianidin, imidacloprid, acetamiprid, and thiacloprid, were separated on LiChroprep^® 100 RP-8 endcapped column using 25% (v/v) acetonitrile with a fl ow rate of 1.0 mL min⁻¹. LiChroprep^® RP-18 (C-18) was chosen as an effi cient adsorbent in d-μ-SPE. The experimental parameters affecting the extraction performance of D-μ-SPE were investigated including salt addition, amount of sorbent, sample volume, and kind and volume of desorption solvent. Under the selected conditions, linearity was found in the range of 0.003-0.1 μg mL⁻¹. Low limit of detection and high enrichment factor (11 – 81) were obtained. The proposed method was successfully applied for the determination of neonicotinoid insecticide residues in surface water and fruit juice samples with high obtained recoveries.