Electrochemical detection of fluoride ions using 4-aminophenyl boronic acid dimer modified electrode

Abstract

Fluoride is a widely used component in dental products, offering benefits such as cavity prevention through bacterial growth inhibition. However, excessive fluoride consumption can lead to fluorosis, which causes tooth discoloration and pitting, and in severe cases, skeletal fluorosis with joint pain and stiffness. Therefore, monitoring fluoride levels in dental products and drinking water is essential. In this study, we developed a rapid electrochemical detection method for fluoride ions using a preanodized screen-printed carbon electrode modified with 4-aminophenylboronic acid dimer (SPCE*/APBAD). The preanodization process involved applying a constant potential of +2 V for 5 min to capture APBAD. The resulting APBAD facilitated a chemical reaction between fluoride ions and boronic acid, forming a fluorophenylboronate complex. This complexation reaction enabled the detection of fluoride ions in a wide linear range (5 µM to 30 mM) with a detection limit of 0.3 µM. The detection behaviour of fluoride ion using SPCE*/APBAD has been studied using cyclic voltammetry, potentiometry, Density Functional Theoretical calculations and flow injection analysis. Furthermore, the practical utility of the sensor was validated by successfully detecting fluoride ions in toothpaste and water samples. The developed method offers a rapid and reliable means of monitoring fluoride ion levels for ensuring safe and beneficial use in dental products and drinking water.