Fluoride Concentration Determination through Calibration Curve and Standard Addition Methods by ISE

3551 Words15 Pages
Abstract: This experiment involves the determination of F¬- ions in Crest® Cavity Protection toothpaste, Minneapolis tap water, and an unknown solution, and comparing the experimental results to values that are expects. The methods of analysis included the usage of a fluoride Ion Selective Electrode (ISE), in conjunction with two methods of interpretation of the voltage provide by the ISE. These methods included a simple calibration curve comparing mV verses pF, and a standard addition method. Each of these methods was prepared by standardized solutions with a known amount of Fluoride in order to have a reference. It was found however that the method of utilizing a calibration curve proved fruitless in determining fluorine ion concentration, as the calculated value of fluoride ion’s in drinking water was 13.29ppm, where the required value by law must fall within the range of 0.9-1.5ppm. Since this calculated value is so ridiculous, the method of standard addition, in which the calculated value of the unknown solution being measured was much higher than the calibration curve (4.81E-3M verses 3.78E-4M), should be a preferred method for calculated low concentration ion solutions compared to that of a linear calibration curve. Introduction: Fluoride is a necessary component in minimizing tooth decay by helping rebuild enamel. Because of this chemicals very effective ability to complete this task, the fluoride ion can be found in toothpaste. The associated salt (NaF) is often put into substances that are utilized every day, such as tap water and certain food products, in order to help prevent dental problems of the general population. The purpose of this experiment is to determine the exact concentration of fluoride in an unknown solution, Minneapolis tap water, and an anti cavity toothpaste (in our case Crest Cavity Protection). The method chosen to conduct this

More about Fluoride Concentration Determination through Calibration Curve and Standard Addition Methods by ISE

Open Document