Analytical Method for Determination of Organochlorine Pesticides in Tea Brews using Single-Drop Microextraction with GC-ECD

The single drop microextraction method was developed for the determination of ten organochlorine pesticides in tea brews using gas chromatograph-electron capture detector. The optimized parameters for effective extraction required a 2 L drop of n-hexane at the tip of a microsyringe immersed in 5 mL of a diluted tea brew sample for 25 min and stirred at 600 rpm. The limit of detection in the range of 0.01 to 0.025 g/L, with relative standard deviation of repeatability and reproducibility, was in the range of 110 and 824%. The relationship of the measured signal was a linear function (>0.9863) of concentration and the recovery method ranged from 92116%. The single drop microextraction method showed the advantage of being easy to operate, low consumption of organic solvent, and high extraction efficiency.