Fluoride Concentration in Samples of Peruvian Salt

Method: Seven 1 kg packages of salt of 3 brands were purchased in two supermarkets of Lima, Peru. Six aliquots of each package were weighed (around 2.5 g) and dissolved in the proportion of 0.025 g/mL of purified water. To 1.0 mL of these solutions, 1.0 mL of TISAB II was added and the activity of ion fluoride in the mixture was determined with specific electrode. To assess the homogeneity of fluoride concentration in the salt, triplicate of 15 g of each package was fractioned in a set of sieves (0.590 to 0.177 mm) and fluoride concentration in each fraction was determined in duplicate. Fluoride concentration in the salt solutions was determined with ion specific fluoride electrode calibrated with standards fluoride solutions ranging from 0.25 to 16.0 µg F/mL, which were mixed with TISAB II containing 0.0125 g NaCL (pa)/mL).

Result: In 4 packages the fluoride concentration found was in accordance with the Peruvian regulation (214.5±10.4; 221.8±14.3; 226.9±19.1 and 237.2±52.0 mg F/kg) but in the other 3 it was lower (145.2±7.9; 145.7±23.3 and 158.4±20.6 mg F/kg). Variability in fluoride concentration was observed either among brands or within the same brand. Also, the fluoride concentration in particles of salt separated by size showed that in none of the package of salts analyzed the concentration was homogeneous (ranging from 72.0 to 1449.7 mg F/kg).

Conclusion: The findings suggest that the manufacturing of fluoridated salt in Peru should be improved. (Supported by FUNCAMP, Proc. 4252)