Determinations for Pesticides on Black, Green, Oolong, and White Teas by Gas Chromatography Triple-Quadrupole Mass Spectrometry.

Black, green, white, and Oolong teas, all derived from leaves of Camellia sinensis, are widely consumed throughout the world and represent a significant part of the beverages consumed by Americans. A gas chromatography-triple quadrupole-based method, previously validated for pesticides on dried botanical dietary supplements, including green tea, was used to measure pesticides fortified into black and green teas at 10, 25, 100, and 500 µg/kg. Teas from 18 vendors of tea products were then surveyed for pesticides. Of 62 black, green, white, and Oolong tea products, 31 (50%) had residues of pesticides for which no United States Environmental Protection Agency tolerances are established for tea. The following pesticides were identified on tea leaves, with concentrations between 1 and 3200 µg/kg: anthraquinone, azoxystrobin, bifenthrin, buprofesin, chlorpyrifos, cyhalothrin, cypermethrin, DDE-p,p', DDT-o,p, DDT-p,p', deltamethrin, endosulfan, fenvalerate, heptachlor, hexachlorocyclohexanes (α,ß,γ,δ), phenylphenol, pyridaben, tebuconazole, tebufenpyrad, and triazophos. DDT-p,p' was found at much higher concentrations than DDE-p,p' or DDT-o,p' in 9 of 10 teas with DDTs. A comparison between three commercially available solid-phase extraction (SPE) column brands of the same type revealed that two brands of SPE columns could be interchanged without modification of the tea method.