Bubble-in-drop microextraction of carbamate pesticides followed by gas chromatography-mass spectrometric analysis

Bubble-in-drop microextraction (BID) is a variation of single-drop microextraction in which an air bubble is deliberately introduced to the solvent to enhance extraction efficiency. Here, BID coupled with GC-MS was developed for the extraction, enrichment and determination of carbamate pesticides in environmental water samples. Conditions affecting BID performance including the type of extraction solvent and its volume, volume of air bubble, extraction time, stirring rate, salt concentration and sample pH were evaluated. Under the most favorable BID conditions, the method provided good linearities from 0.05 to 20.0 mu g L-1 with the coefficients of determination higher than 0.99. Enrichment factors were determined to be between 536 and 1097. The limits of detection and limits of quantification were in the ranges of 0.02 to 0.04 mu g L-1, and 0.05 to 0.13 mu g L-1, respectively. BID-GC-MS was successfully applied to the determination of carbamate pesticides in water samples with satisfactory recoveries from 81.7% to 99.0%, and intra-day and inter-day precision (relative standard deviations of <7% and <8%, respectively).