Monitoring of fluoride in the public water supply using electrometric or colorimetric analyses

Abstract The surveillance of the concentration of fluoride in the public water supply aims to ensure the balance between the benefits (carie prevention) and risk (dental fluorosis) of water fluoridation programs. The aim of this study was to check the accuracy of two analytical methods for monitoring the concentration of fluoride in the public water supply of a Brazilian city. The STROBE checklist was used to aid the conduction of this study and report the results. It was an analytical, observational, and prospective study using the water supply of Uberlândia, MG, Brazil. We collected 126 water samples at 21 sites for six consecutive months and analyzed them using the fluoride ion selective electrode (F-ISE) method and colorimetry with SPADNS. The statistical analysis was performed descriptively and then the ANOVA and Student t-test for paired samples were applied. The results showed that the F-ISE method had a lower coefficient of variation (12.3%) than the SPADNS method (57.4%). There was no significant variation of the fluoride concentration in the water through the supply network evaluated either by F-ISE as SPADNS. We concluded that the electrometric method should be the first choice for use by laboratories that monitor fluoride concentration in the public supply water.