Dispersive liquid-liquid microextraction combined with sweeping micellar electrokinetic chromatography for the determination of some neonicotinoid insecticides in cucumber samples

A rapid, simple and sensitive method has been developed for the analysis of some neonicotinoid insecticides in cucumber samples by using dispersive liquid-liquid microextraction (DLLME) coupled with sweeping in micellar electrokinetic chromatography (MEKC). Under optimised conditions, the enrichment factors were achieved in the range from 4000 to 10,000. The linearity of the method was in the range from 2.7 to 200 ng g(-1), for thiacloprid, acetamiprid and imidacloprid, and in the range from 4.0 to 200 ng g(-1) for imidaclothiz in cucumber samples, with the determination coefficients (r(2)) ranging from 0.9924 to 0.9968. The limits of detection (LODs, S/N = 3) ranged from 0.8 to 1.2 ng g(-1). The relative standard deviations (RSDs) at the concentration levels of 10.0 and 50.0 ng g(-1) each of the neonicotinoid insecticides in cucumber samples varied from 3.8% to 6.3%. The developed method has been successfully applied to the analysis of the neonicotinoid insecticides in cucumbers with a satisfactory result. (C) 2012 Elsevier Ltd. All rights reserved.