Simultaneous Analysis of Pesticides Residual in Black Tea and its Infusion- a Study of Risk assessment

Background: A simple and accurate analysis method based on QuEChERS procedure was validated and developed by gas chromatography/tandem mass spectrometry (GC-MS/MS) for the simultaneous determination of 33 pesticide residues in 60 black tea samples and the measurement of transfer rate of pesticides during brewing.Materials and Methods: The detection of pesticides was done by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring (MRM) mode. The efficiency of the method for all pesticides was evaluated in terms of linearity (R2> 0.99), recoveries ranged from 72% to 121% with relative standard deviations (RSDs) lower than 20%.The limits of detection (LOD) and the limits of quantification (LOQ) ranged from 0.09 to7.26 μg/kg and 1.5 to 24 μg/kg, respectively.Results: The results obtained showed pesticide residue in 52(86%) out of tea samples was above of the LOD. Twenty-four (40%) of the samples contained pesticide more than of maximum residue limit (MRL) set by EC. The most transfer rates of detected pesticides (buprofezin, trifluralin, hexaconazole, chlorpyrifs, and triflumizole) of made tea to the brewing was related to hexaconazoleand followed by triflumizole. The concentrations of pesticides during infusion clearly decreased with the increase of the brewing time.Conclusion: The risk assessment study for detected pesticides in brewing tea samples indicated there was no health risk for consumer.

Keywords:

Pesticides reside , Black tea , QuEChERS , GC-MS/MS , Risk assessment