Directly coupled high performance liquid chromatography - Inductively coupled plasma-mass spectrometry for the determination of organometallic species in tea

Organometallic complexes in three teas (Kenyan, Indian, and Chinese) have been studied by directly coupled high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) and a desolvation interface. The use of a polymer-based reverse phase column (Hamilton PRP-1) reduced interactions of the complexed metals with the stationary phase below those in a silica-based column. The optimal chromatography was found to be isocration elution using 90% dilute (2%) aqueous acetic acid and 10% acetonitrile at 1.0 ml min(-1). Organometallic forms of Cd, Cu, Hg, Mn, Mo, Ni, Pb, Sr, and Zn were found primarily associated with the flavanoid components. The organic components were confirmed using UV absorption detection. The organometallic complexes in the black teas (Kenyan and Indian) appear to be larger and less hydrophilic than those from the green tea(Chinese). (C) 1996 Academic Press, Inc.