Fluoride Testing (Arsenic-Free)

Instrumental Kits

Range Method Type Kit Cat. No.
0-3.00 ppm SPADNS (Arsenic-free) Vacu-vials K-4009
0-3.00 ppm SPADNS (Arsenic-free) SAM Photometer + Vacu-vials I-2021

New to the CHEMetrics range is an instrumental colourimetric test kit for the determination of Fluoride in aqueous solutions. The CHEMetrics Fluoride MDL+ Kit employs the Arsenic-Free SPADNS method, a non-toxic but equally effective alternative to the traditional SPADNS-based Fluoride test. Arsenic is carcinogenic and can potentially complicate disposal procedures. Each kit contains 27 tests. Suitable for potable water and industrial effluent testing.

The SPADNS (Arsenic Free) Method

The CHEMetrics Fluoride MDL+ Kit is based on the reaction between fluoride and a red zirconium-dye lake that has been formed with SPADNS. The extent of colour loss through reaction of fluoride with the dye lake is proportionate to the flouride concentration in the sample. The reagent is formulated with ascorbic acid to prevent chlorine interference. Analysis time is less than 2 minutes. The extent of colour loss in the reagent is measured using the V-3000 or SAM Photometer, or a spectrophotometer* with a cell size up to 50mm.

The CHEMetrics Fluoride MDL+ Kit, catalogue number K-4009, is a portable, instrumental test kit. Kit comes in a cardboard box and contains everything required to perform up to 27 tests.

APHA Standard Methods, 22nd ed., Method 4500 F- D - 1997.
USEPA Methods for Chemical Analysis of Water and Wastes, Method 340.1 (1974, 1978).
Bellack, E. and P.J. Schoube, 1958, Rapid Photometric Determination of Fluoride with SPADNS - Zirconium Lake. Anal. Chem. 30:2032.

* MDL+ reagent ampoules may be used in photometers and spectrophotometers applying user-generated calibrations. Such calibrations should be produced by means of established methodology using NIST-traceable Fluoride standards covering the dynamic range of the analysis. Neither Galgo nor CHEMetrics make any claims as to the accuracy of a user-generated calibration. The analyst must determine the suitability of a user-generated calibration subject to the operating conditions and specific instrument capabilities.


Fluoride is naturally occurring in most groundwater, rivers and lakes. Fluoride may also be added to municipal water in controlled amounts by injection of either hydrofluorosilicic acid, sodium silicofluoride or sodium fluoride, as part of local dental health initiatives. The upper limits in England and Ireland are 1.5 mg/l and 0.8 mg/l respectively. Fluoride salts are only mildly toxic but elevated fluoride levels in drinking water may contribute to skeletal fluorosis. Careful monitoring of dosing levels in potable water supplies is therefore of the utmost importance. Fluoride salts are also involved in the production of steel, aluminium, and uranium, as well as cement, enamel, and plastics.

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