Rapid analysis of organochlorine and pyrethroid pesticides in tea samples by directly suspended droplet microextraction using a gas chromatography-electron capture detector.

A simple and efficient directly suspended droplet microextraction (DSDME) has been developed to extract and pre-concentrate organochlorine and pyrethrin pesticides from tea samples prior to analysis by a gas chromatography-electron capture detector (GC-ECD). The optimal experimental conditions of DSDME were: 100 μL isooctane exposed for 15 min to 5 mL of the tea aqueous sample stirred at 1100 rpm. For most of the target analytes, the optimal pretreatment of DSDME processes led to no significant interference of tea matrices. The approach was applied to the determination of organochlorine and pyrethroid pesticides in tea samples, with a linearity range of 0.0005-2 μg/mL. The relative recoveries of all the pesticides ranged between 80.0% and 120.8% with relative standard deviations (RSDs) in the range of 0.8-19.9% (n=5). The limits of detections (LODs) ranged between 0.04 and 1 μg/L for all the target pesticides.