Journal of the Brazilian Chemical Society
Print version ISSN 0103-5053
BRAGA, Otoniel C.; CAMPESTRINI, Iolana; VIEIRA, Iolanda C. and SPINELLI, Almir. Sulfadiazine determination in pharmaceuticals by electrochemical reduction on a glassy carbon electrode. J. Braz. Chem. Soc. [online]. 2010, vol.21, n.5, pp.813-820. ISSN 0103-5053. http://dx.doi.org/10.1590/S0103-50532010000500008.
Sulfadiazine was quantified in two samples of pharmaceutical preparations by square-wave voltammetry. The analytical signal response was obtained by electrochemical reduction instead of oxidation of the sulfa drug at a glassy carbon electrode. The determination was carried out in 0.04 mol L-1 Britton-Robinson pH 6.8 buffer solution. Sulfadiazine reduction was observed at -1.49 V vs. Ag/AgCl in one well-resolved irreversible peak. The analytical curve was obtained in the concentration range of 62.7 to 340 µmol L-1 (r = 0.9986) with a detection limit of 10.9 µmol L-1. For one sample analyzed, recovery values were in the range of 94.9 to 101.1%, while for the other sample they were within 96.0 to 104.6%, indicating no matrix interference effects on the analytical results for both sulfadiazine samples. The accuracy of the electroanalytical method was compared to the standard amperometric titration method.
Keywords : sulfadiazine; pharmaceuticals; electrochemical reduction; square-wave voltammetry; glassy carbon electrode.