Kinetic-Spectrophotometric Determination of Thiocyanate in Human Saliva Based on Landolt Effect in Presence of Astrafloxine FF

Abstract

In the present study a kinetic-spectrophotometric method for thiocyanate determination is described. The suggested method for the determination of thiocyanate is based on its “Landolt effect” on the reaction of bromate with hydrobromic acid, which leads to the formation of only one halogen bromine. The reaction was monitored spectrophotometrically at the maximum wavelength of astrafloxine FF light absorption at 535 nm. The absorbance of reactants mixture decreased with an increase of the reaction time. The calibration curve for thiocyanate determination was obtained in the concentration range of 0.03–2.0 μg mL⁻¹ under the optimal conditions (pH 1.5; C_BrO3- = 7.6 × 10^-4 mol L^-1; C_{astrafloxine FF} = 1 × 10^-5 mol L^-1). The limit of detection was 0.01 μg mL⁻¹. The method was successfully applied to the determination of thiocyanate in human saliva samples with satisfactory results.