I U X2 More Formatting A A Q 4. A fluoride ion selective electrode was used to analyse for fluoride as part of the QC procedures during the production of Listerine Fluoride Defense Anticavity Mouthwash. The mouthwash contains 0.02% sodium fluoride which is equivalent to 90 ppm of fluoride. The QC specification for the mouthwash is 90 ± 5 ppm of fluoride. During production three standards and six periodic samples were analysed each hour. The mouthwash samples were diluted 100 fold before the pH and ionic strength were adjusted using an appropriate TISAB before analysis. The following data was obtained for the standards and the calibration curve is shown below. (i) (ii) Solution E (MV) 1.00 x 104 MF 40.5 5.00 x 10-5 MF 1.00 x 10-5 M F 60.2 100.0 Six samples were analysed and the following potentials, measured in mV, were obtained; 58.9, 61.0, 60.7, 59.3, 59.6 and 61.7. Use this data to determine the fluoride concentration in the mouthwash in ppm (RAM fluoride 19.0). Comment on whether the levels of fluoride found in the mouthwash conform to the QC specifications.