Determination of Multiple Pesticides Residues in Imported Tea in UAE Using Liquid and Gas Chromatography Tandem Mass Spectrometry

摘要

An accurate, rapid and reliable method for the simultaneous determination of 48 pesticide residues in United Arab Emirates imported tea by liquid and gas chromatography coupled with tandem mass spectrometry LC-MS/MS and GC-MS/MS is proposed. Samples purified by a modified quick, easy, cheap, effective, rugged, safe (QuEChERS) method, and analyzed by LC-ESI (+)-MS/MS and GC-EI-MS/MS in the presence of internal standards. In this research, in-house validation method applied to the quantification of pesticide residues contained in real tea samples obtained from local markets, which greatly improved the detection performance and the range of pesticide multi-residues. Five replicates samples of three green tea brands and five replicates samples of five black tea brands in addition to five replicates of two slimming tea brands available in UAE market were collected during 2014-2015 and analyzed. Buprofezin and Acetamiprid pesticides were found in green tea samples but at lower concentration levels, below the Maximum Residue Levels (MRL) values set by the CODEX and EU. Also, Difenoconazole found in slimming tea at lower concentration levels, below the Maximum Residue Levels (MRL).