Determination of benzimidazole anthelmintics using HPLC after vortex-assisted mixed anionic–cationic surfactant-enhanced emulsification microextraction with solidification of floating organic droplet procedure

A new approach based on vortex-assisted surfactant-enhanced emulsification microextraction with solidification of floating organic droplet (VASEME–SFO) using mixed anionic–cationic surfactant as emulsifier was developed for the preconcentration of benzimidazole anthelmintics prior to HPLC analysis. Binary mixtures of anionic–cationic surfactants formed by anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) were used to enhance the extraction efficiency of benzimidazoles. 1-Octanol was used as an extraction solvent. The optimum conditions of the mixed anionic–cationic VASEME–SFO, were 0.01 mol L−1 SDS, 0.01 mol L−1 CTAB, 300 μL 1-octanol, 5% (w/v) Na2SO4, vortex time 1 min and centrifugation time 10 min. Linearity was found over the range 5–1000 μg kg−1, with correlation coefficients greater than 0.99. The high enrichment factor of the target analytes was in the range 33–60 and low limit of detection (0.3–0.5 μg kg−1) could be obtained. This newly established procedure was successfully applied for the analysis of benzimidazole residues in liver and kidney samples.