Pesticide residues in tea leaves always raise public concerns as drinking tea is an integral part of everyday routine for many people. Also, pesticide residues may cause acute or chronic adverse health effects. There are hundreds of pesticides in the tea and the residue level of pesticide in the tea brew is closely related with the water solubility of pesticide. The higher water solubility of pesticide showed higher extractive rate of pesticide during the brewing process from dry tea. With development of new technology, an efficient and sensitive method has been established for simultaneous determination of 653 pesticides in teas by GC/MS and HPLC/MS/MS. The method involved extraction with acetonitrile followed by clean up using Agela's Cleanert-TPT SPE and subsequent identification and quantitation of 490 pesticides by GC/MS and 448 pesticides by HPLC/MS/MS. more information