THE USE OF SILICA-TITANIA XEROGELS FOR THE SOLID PHASE SPECTROPHOTOMETRIC DETERMINATION OF FLUORIDE IONS IN THE ARTIFICIAL SALIVA
Silica-titania xerogels modified with the pyrocatechol violet have been proposed as new sensor materials for fluoride determination in the artificial saliva. The determination is based on the ability of fluoride ions to disrupt the colored titanium(IV)-pyrocatechol violet complexes. The complex reactions of matrix embedded titanium(IV) with pyrocatechol violet (resulting in blue colored xerogels) and with fluoride ions (resulting in bleaching of colored xerogels) have been investigated. The selected conditions have been used for developing the procedures of fluoride determination in the artificial saliva and water. Varying the volume of the analyzed solution two analytical ranges (0.05-1 ppm (LOD 2 ppm) and 5-100 ppm (LOD 0.02 ppm)) have been obtained. The procedures’ accuracy has been evaluated using the spiked probes of the artificial saliva achieving the RSD of 5-23%. The developed sensor materials can be used for studying the efficiency of various fluor-containing products for medical diagnostics, scientific research, and also for the construction of new dental materials.