Gradient flow titration for the determination of fluoride ion in natural waters

The determination of fluoride ions in water samples was accomplished by usi ng a gradient flow titration. A standard commercial combined electrode is u sed in a cell configuration that combines the gradient chamber and the elec trode in a single unit. The methodology developed gives results with a rela tive standard deviation of about 3%. The average recoveries after spiking n atural samples with fluoride are in the range 100-102%. The method was used successful in determining the fluoride concentration in water samples. (C) 2000 Elsevier Science B.V. All rights reserved.