A series of test samples with varying concentrations of fluoride ranging from 0.1 to 100 mg/L were prepared by dissolving 0.2210 g of NaF in 1 L of de-ionized (DI) water and diluted as per the required concentration. 40 μL of 4% TBDPSC solution prepared in THF was then added to 1 mL of each of these solutions.