Yaygın İnorganik Anyonların Çay Örneklerinde İyon Kromatografik Tayini

Abstract

A simple, rapid, and accurate technique based on ion chromatography coupled with a suppressed conductivity detector was described to determine the inorganic anions – fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulphate in tea bag samples. A Dionex IonPac AS9-HC 4×250 mm analytical column with a Dionex IonPac AG9-HC 4×50 mm guard column was used for the chromatographic separation of the analytes. The eluent was 12 mM KOH and the limit of quantification for the inorganic anions were in the range 0.02 - 0.20 mg L-1. Tea infusions were prepared traditionally by pouring the tea bags with 200 mL of boiling ultra-pure water. Influence of the brewing time on the extraction of inorganic anions from the tea bags was examined and optimum brewing time was determined as 6 min according to the results obtained. Finally, the ion chromatographic technique was applied to analyze the inorganic anions in some black, green, and white tea bag samples and five anions were determined quantitatively. The nitrite and bromide amount in all the samples were well below the quantification limit of the method.