engleski

Determination of total fluoride content in teas by using fluoride ion-selective electrode

The total fluoride content was analyzed in 30 tea samples. The analyzed samples were chamomile (Matricaria chamomilla), green tea (Camellia sinensis) and mint (Mentha piperita) in tea bags and bulk purchased at local supermarkets and marketplaces in Split, Croatia, were determined. Tea samples were digested in microwave in nitric acid and hydrogen peroxide mixture. Potentiometric determination by using fluoride ion-selective electrode was applied in this work. Average F− concentration in all tested samples was 0.183±0.161 mg L−1. In order to get a better insight into the fluoride content in different plant samples, a One-Way ANOVA (program R) was used for statistical data analysis. Concentration of F− follows normal distribution. F− concentrations (P < 0.001) were higher in bulk samples (0.354±0.039 mg L−1) than in tea bags ones (0.111±0.007 mg L−1) of mint samples. F− content was not statistically different among plant samples. Green tea samples have total content in range from 0.0163 to 0.509 mg L−1. Chamomile samples have total content in range from 0.0001 to 0.4367 mg L−1 with the highest recorded dispersion. When the total fluoride contents are compared with data of ones in tea infusion, it can be seen that the biggest fluoride extraction occurs during green tea brew.

uoride; tea; potentiometric; determination; ion-selective electrode

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