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.