Potentiometric determination of nitrate in products used for the treatment of dentinal hypersensitivity

Abstract

In this paper, a rapid, simple and inexpensive potentiometric method for the determination of the potassium nitrate contained in different dentinal desensitizer products is described. The nitrate-selective electrode, using a tetraoctylammonium salt as sensor, was constructed without an internal filling solution. The ionic strength of the sample solutions was fixed by means of a 0.33 mol l −1 K 2SO 4 solution and direct potentiometry was used as the analytical technique of measurement. Precision and accuracy of the method developed were adequate since the mean of the relative standard deviations was 1.2% and the average percentage of spike recoveries was 100.9%. Eleven samples of toothpastes, gels and mouthwashes were analyzed by the proposed potentiometric method and the quality of the results was compared by means of linear regression analysis with those obtained by high-performance liquid chromatography (HPLC), adopted as the reference technique. Satisfactory agreement was observed.