Analysis of Abamectin Residues in Green Tea Using QuEChERS Method and Liquid Chromatography-tandem Mass Spectrometry

The present study estimated the residue levels of abamectin (B-1a) in green tea leaves and tea infusion. Samples were hydrated with water prior to extraction by using the quick, easy, cheap, effective, rugged, safe method and was analyzed with liquid chromatography-tandem mass spectrometry in positive ion mode. The matrix-matched calibration was linear over the concentration range of 0.01-2 mg/kg with determination coefficients (R-2) >0.995. Recovery rates at two spiking levels (0.1 and 0.5 mg/kg) ranged between 80.5-99.7% with a relative standard deviation <11%. The compound was stable at 20 degrees C for 174 days with a recovery estimate of 109.9%. Although the maximum residue limit was not established by the Ministry of Food and Drug Safety, Republic of Korea, the limit of quantitation was very low at 0.01 mg/kg. The method was successfully applied to field incurred samples and detected residue of 0.02 mg/kg in green tea samples sprayed twice (7-3 days). Abamectin was not transferred to tea infusion.