Analytical Sciences

Amperometric Determination of Hydrogen Peroxide in Whitening Gels Using Boron-doped Diamond Electrode

Gustavo C. AZEVEDO, Roberto H. S. CASTRO, Maria Auxiliadora C. MATOS, and Renato Camargo MATOS

NUPIS (Núcleo de Pesquisa em Instrumentação e Separações Analíticas), Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, 36036-330, Juiz de Fora, MG, Brazil

The aim of this work was to develop an electrochemical cell and a methodology based on an amperometric determination of hydrogen peroxide in whitening gel samples under a boron-doped diamond electrode using flow injection analysis. Different parameters were evaluated to obtain the best conditions of analysis: among them, the flow of electrolyte at 2.8 mL min⁻¹, the loop sampling 175 μL (28.5 cm), an analytical length of 159 μL (25 cm) and an applied potential of +0.60 V vs. Ag/AgCl_(sat). The proposed method was suitable in terms of precision of results (RSD <10%); the accuracy was confirmed in the analysis of the gels through addition and recovery studies with results between 74 and 107%. The method was then applied to the analysis of tooth-whitening gel samples, acquired in different cities of the region. Regarding the results, a medium concentration value of 2.39% (w/w) was observed.

J-STAGE: View this article in J-STAGE