Determination of Inorganic Anions in Chinese Tea by Ion Chromatography and Its Application to Classification of Tea

Ion chromatography was applied to the determination of F-, Cl-, NO2-, Br-, NO3-, H2PO4- and SO42- in Chinese tea. Shodex IC SI-52 4E anion-exchange column was used for separation, and a mixed solution of 3.6 mmol·L-1 Na2CO3 solution and methanol mixed in the ratio of 98 to 2 by volume was used as eluent. A total of 16 kinds of tea samples of different categories were taken as testing samples, based on the different contents of the 7 inorganic anions, the tea samples were classified by applying the clustering analysis.