DETERMINATION OF IONIC SPECIES IN TEA INFUSIONS BY ION CHROMATOGRAPHY

The distribution levels of inorganic anions of tea infusions were measured either for monitoring consumers' health issues, or for optimization of manufacturing processes. A simple, rapid, and accurate method was used for the quantitative determination of fluoride, chloride, nitrate, phosphate, and sulphate ions in green, black, and white tea infusions, by ion chromatography with conductometric detection. The separation was performed using an anion-exchange column at 30 degrees C by isocratic elution with an aqueous 1.7 mM Na2CO3 + 1.8 mM NaHCO3 eluent. Without special sample processing, the method was successfully applied for 24 tea types available in Romanian shops. The ionic content was subjected to multivariate analysis in order to reduce dimensionality and detect the factors responsible for the registered variability.