Specific Ion Electrode Determination of Fluoride in Multivitamin Preparations

A simple, rapid, and specific method for direct determination of ionized fluoride in multivitamin preparations is described. Samples and fluoride standards, prepared in a high-ionic strength buffer solution (1 M tris-HCl buffer), are measured directly using a fluoride-specific ion-activity electrode. Total ionized fluoride in the measured sample solution is obtained from a standard fluoride calibration curve. The time required for electrode recalibration and subsequent analysis is significantly reduced by using the indicated single-point technique of standardization and determination. Precision and accuracy studies are included.