Low-density extraction solvent-based solvent terminated dispersive liquid-liquid microextraction combined with gas chromatography-tandem mass spectrometry for the determination of carbamate pesticides in water samples.

A simple and fast method of low-density extraction solvent-based solvent terminated dispersive liquid-liquid microextraction (ST-DLLME) was developed for the highly sensitive determination of carbamate pesticides in the water samples by gas chromatography-tandem mass spectrometry (GC-MSMS). After dispersing, the obtained emulsion cleared into two phases quickly when an aliquot of acetonitrile was introduced as a chemical demulsifier into the aqueous bulk. Therefore, the developed procedure does not need centrifugation to achieve phase separation. It was convenient for the usage of low-density extraction solvents in DLLME. Under the optimized conditions, the limits of detection for all target carbamate pesticides were in range of 0.001-0.50 ng mL(-1) and the precisions were in the range of 2.3-6.8% (RSDs, 2 ng mL(-1), n=5). The proposed method has been successfully applied to the analysis of real water samples and good spiked recoveries over the range of 94.5-104% were obtained. Copyright 2009 Elsevier B.V. All rights reserved.