Re: Assay of flouride levels in drinking water.

To the Editor: With great interest we read the article about fluoride levels in drinking water in the central province of Saudi Arabia.1 In this study, the fluoride concentration was measured by the atomic absorption spectrophotometry method. There are some standard methods for assay of fluoride in the scientific literature, which include: 1) ion-selective electrode, 2) colorimetry, 3) complexone, 4) ion chromatography, and 5) electrometry. 2,3

Atomic absorption spectrophotometry is usually used for assay of cationic metal ions such as potassium, iron, lead, etc.3 Atomic absorption spectrophotometry is a questionable method for assay of fluoride concentration in drinking water and has not been documented.