Application of clean-up using a ternary liquid phase system combined with preconcentration by a microextraction method in analysis of seven pesticides from soya milk.

BACKGROUND: A method has been developed based on a three-phase system followed by dispersive liquid-liquid microextraction for the extraction of seven pesticides from soya milk prior to their analysis by gas chromatography-flame ionization detection. The base of this method is different extraction capability of the components of soya milk by each involved phases. In this procedure, a homogeneous solution consists of soya milk and a water-miscible solvent (acetonitrile) is separated two phases in the presence of Na2 SO4 and the analytes are extracted into the produced acetonitrile droplets. The acetonitrile phase is mixed with a preconcentration solvent to perform the next microextraction procedure for further enrichment of the analytes.

RESULTS: Limits of detection and quantification were obtained in the ranges of 0.11-0.35 and 0.35-1.20 μg L-1 , respectively. Enrichment factors and extraction recoveries were in the ranges of 562-933 and 56-93%, respectively. The relative standard deviations were ≤7% for intra- (n = 6) and inter-day (n = 5) precisions at two concentrations of 10 and 50 μg L-1 of each analyte.

CONCLUSION: The proposed method was applied to the analysis of the pesticides in soya milk samples at μg L-1 concentration. This article is protected by copyright. All rights reserved.