Analytical Sciences

Rapid Method for the Determination of Trace Fluoride and Activation of Ion-Selective Electrode

Sheng-xun SHI,*  Zhi-guang ZHU,* Ran SUO,** and Chun WANG***

*College of Chemistry and Environmental Science, University of Hebei, Baoding 071002, China
**College of Food Science, Agricultural University of Hebei, Baoding 071001, China
***College of Science, Agricultural University of Hebei, Baoding 071001, China

A method for activating ISE is proposed that can allow determination of the fluoride concentration at ng mL^-1 level with good precision and accuracy. Fluoride ISE is activated in 0.5 mol L^-1 HClO₄ medium and then fluoride is determined in the same medium. The linear range for the determination of fluoride is between 1.00 x 10^-2 - 1.00 x10^-7 mol L^-1, and the detection limit of the method is 1.0 ng mL^-1. The advantage of this method is that it is free from the use of TISAB solution while being, time-saving and labor-saving. A mechanism study of the activation of FISE in HClO₄ medium is explained. The method has been used for the determination of trace fluoride in milk and flour with satisfactory results.

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