Dye-assisted analysis of fluoride in water using UV–visible spectrophotometry: a preliminary study

Abstract

Dye-assisted method for the analysis of fluoride content of water has been developed in this study using dyes obtained from some flowering plants. This was done to evaluate the potentials of locally accessible dyes in spectrophotometrically detecting F– levels in fluoride-containing water samples. Dye solutions obtained from scarlet jungle flame, Hibiscus flower, Peacock flower or Barbados pride, Royal poinciana, Pink bauhinia, Barbados lily, or Easter lily were adopted to monitor absorbance and corresponding concentrations of serially prepared F concentrations in a range of 0.001–0.012 ppm. Dye from the Hibiscus flower gave an optimal performance with R2 ¼ 0.9792. Using this dye, the F– content in water samples obtained from tap waters from Moremi Estate, Modomo, Asherifa, Postgraduate Hall of Obafemi Awolowo University, Ile-Ife, and a well water sample from Modomo gave 0.052, 0.053, 0.053, 0.058, and 0.061 ppm, respectively. A comparison of these values indicated that all the water samples monitored were safe for human consumption without experiencing health challenges as the maximum F– limit for potable water recommended by WHO was not exceeded. This study concluded that dye from Hibiscus flower could satisfactorily assist in monitoring F– content in water where ion-selective electrodes are not readily accessible.