Development of salt and pH–induced solidified floating organic droplets homogeneous liquid–liquid microextraction for extraction of ten pyrethroid insecticides in fresh fruits and fruit juices followed by gas chromatography-mass spectrometry

Abstract

A new microextraction method named salt and pH–induced homogeneous liquid-liquid microextraction has been developed in a home–made extraction device for the extraction and preconcentration of some pyrethroid insecticides from different fruit juice samples prior to gas chromatography–mass spectrometry. In the present work, an extraction device made from two parallel glass tubes with different lengths and diameters was used in the microextraction procedure. In this method, a homogeneous solution of a sample solution and an extraction solvent (pivalic acid) was broken by performing an acid–base reaction and the extraction solvent was produced in whole of the solution. The produced droplets of the extraction solvent went up through the solution and solidified using an ice-bath. They were collected without centrifugation step. Under the optimum conditions, limits of detection and quantification were obtained in the ranges of 0.006–0.038, and 0.023–0.134ngmL–1, respectively. The enrichment factors and extraction recoveries of the selected analytes ranged from 365–460 to 73–92%, respectively. The relative standard deviations were lower than 9% for intra– (n = 6) and inter–day (n = 4) precisions at a concentration of 1ngmL–1 of each analyte. Finally, some fruit juice samples were effectively analyzed by the proposed method.