KINETICS AND EQUILIBRIA OF TEA INFUSION .12. EQUILIBRIUM AND KINETIC-STUDY OF MINERAL ION EXTRACTION FROM BLACK ASSAM-BUKIAL AND GREEN CHUN-MEE TEAS

The rates of infusion into distilled water of caffeine and of Cl-, H2P O4-, SO42-, C2O42-, K+ and Mg2+ ions have been measured at 80 degrees C, using both black orthodox Bukial and green Chun Mee tea leafs in th e size range 1.70-2.00 mm. The analytical techniques employed were HPL C and ion chromatography. The total moles of positive charge extracted per litre of infusion were several times as large as the moles of neg ative charge of all the anions analysed, pointing to large concentrati ons of organic anions including polyphenolates. The kinetic data were fitted to first order plots. From the resultant rate constants the dif fusion coefficients of the various species within the tea leafs were c alculated and compared with the corresponding diffusion coefficients i n pure water at 80 degrees C. The hindrance factors in the leafs were all of the order of 10(2).