Determination of fluoride in black, green and herbal teas by ionselective electrode using a standard-addition method

<span style="font-family: TribuneItalic; font-size: 9pt; color: #000000; font-style: normal; font-variant: normal;"><em>Tea leaves are very rich in fluoride, since tea plants take up fluoride from the soil and accumulate in its leaves. Some of this </em><span style="font-family: TribuneItalic; font-size: 9pt; color: #000000; font-style: normal; font-variant: normal;"><em>fluoride is released into the infusion, which is drunk as tea. Fluoride in tea could be beneficial for the prevention of dental caries, but </em><span style="font-family: TribuneItalic; font-size: 9pt; color: #000000; font-style: normal; font-variant: normal;"><em>it may result in excessive intake and lead to enamel fluorosis. The purpose of this work was to determine the fluoride levels in 12 </em><span style="font-family: TribuneItalic; font-size: 9pt; color: #000000; font-style: normal; font-variant: normal;"><em>different brands and types of tea by means of a computer-controlled ion-selective electrode potentiometry using a standard-addition </em><span style="font-family: TribuneItalic; font-size: 9pt; color: #000000; font-style: normal; font-variant: normal;"><em>method. It is a rapid method which showed good accuracy and precision. Fluoride contents of tea infusions after 5 min ranged from </em><span style="font-family: TribuneItalic; font-size: 9pt; color: #000000; font-style: normal; font-variant: normal;"><em>0.95 to 4.73 mg/l for black teas; from 0.70 to 1.00 mg/l for green teas, and from 0.26 to 0.27 mg/l for herbal teas. It was concluded </em><span style="font-family: TribuneItalic; font-size: 9pt; color: #000000; font-style: normal; font-variant: normal;"><em>that black teas and green teas examined may be important contributors to the total daily fluoride intake. However, the ingestion of </em><span style="font-family: TribuneItalic; font-size: 9pt; color: #000000; font-style: normal; font-variant: normal;"><em>some black teas that were found to have high fluoride content by children at the age of risk to dental fluorosis should be avoided.</em></span></span></span></span></span></span></span><br style="font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" />