Air-assisted liquid–liquid microextraction used for the rapid determination of organophosphorus pesticides in juice samples

A novel and simple air-assisted liquid–liquid microextraction (AALLME) is introduced to analyze the organophosphorus pesticide (OPP) residues in fruit juice samples, using the gas chromatography-flame photometric detection (GC-FPD). In this method, fine extraction solvent drops are rapidly formed and dispersed into the aqueous samples, by using a syringe to withdraw and push-out the mixture of aqueous sample solution and extraction solvent several times. The parameters affecting the extraction efficiency were investigated including the type and volume of the extraction solvent, salt addition, extraction times, and pH. Under optimized conditions, the method showed good linearities with the correlation coefficients (γ) higher than 0.9988, and the sensitivity with the limits of detection (LODs) between 0.02 μg L−1 and 0.6 μg L−1. The method was applied to determine the OPP residues in juice samples and the recoveries were ranged from 79% to 113% with relative standard deviations (RSDs) of 0.4–9.9%. The feasibility of the method in real samples was proved.