Determination of Fluoride Ion in Different Samples of Teaand Coffee Circulating in the Libyan Market Using FluorideSelective Electrode

Abstract

Tea and coffee are one of the most popular drinks in the world due to its many and varied benefits. It is known that the content of fluoride in tea leaves reaches to 400 mg / kg, but its concentration in tea infusion drinks after preparing tea ranges between (0.5 - 1.50 mg /L), and the amount of fluoride in a single cup of tea does not depend only on its size, but also depends on the type of tea, the amount used, and the period of steeping, whether it is boiled or if the tea was prepared in advance with water containing fluorine. 58 different brands and types of tea, coffee and Nescafe were collected from Libyan Market, where they were dried and a certain weight was taken, after that, the process of boiling tea and coffee was carried out at a temperature of 100 ^oC and at four different time periods where each sample was repeated three different times, and was finally measured by (Ion Meter). The obtained results showed that the concentration of fluoride ion in ordinary red tea is higher than the concentration of it in regular green tea, exception of Chinami green tea infusions, the concentration of fluoride  in it (1.526±0.032 mg /L) and was higher than other samples of regular green and red tea  infusions. The concentration of fluoride in the sachet tea syrup (tea bags : red, green, and flavors) was close, so the highest concentration of it was in  red LOYD tea sample (0.66 ±0.01 mg /L), and the lowest concentration of it was in  Ahmed tea with chamomile and lemon flavor (0.198±0.01 mg /L), and the lowest concentration was in coffee BON AROMA branded Nescafe (0.0065±0.0005 mg /L) and the highest concentration in INTE NSO GOLD branded Nescafe coffee (0.0192±0.0004 mg /L). The results also showed that the time factor does not affect the concentration of fluoride ion after preparation the tea and coffee, as it was found that the fluoride ion may be released quickly from the tea leaves when boiled in water more than 10 minutes.  The results obtained from this study showed that the fluoride ion concentration in all studied samples was within the limitation of WHO standards, except the Chenmai green tea syrup , and the concentration of fluoride in it was (1.562 ± 0.032 mg /L)