Polarographic Study About The Determination Of Fe(iii) Using The Technique Of Differencial Pulse Polarography [estudo Polarográfico Sobre A Determinação De Fe(iii) Utilizando-se A Técnica Da Polarografia De Pulso Diferencial]

Abstract

A differential pulse polarographic study with the objective to determine iron (III) in presense of copper (II) in a supporting electrolyte based on citrate -EDTA was made. The best experimental conditions found were a supporting electrolyte of citrate 0.25 mol L-1, EDTA 0.050 mol L-1 and KNO3 0.50 mol L-1, pH 5.00. In this media iron (III) showed a polarographic peak in -0.08 V and the copper (II) in -0.34 V, both vs. Ag/AgCl (saturated KCl). Thus, a analytical method was developed and applied to determine iron (III) in brass alloy, a matrix were copper is in large excess over iron. The results obtained showed no interference of copper in the iron determination. The value of 0.21% of iron in the sample alloy composition was obtained and the method was validated by atomic absortion and recovery test, and the results exhibited a good agreement with the proposed method.246790794Bond, A.M., (1980) Modern Polarographic Methods in Analytical Chemistry, , M. Dekker, New YorkWang, J., (1985) Stripping Analysis, , VCH Publishers, Deerfield BeachLu, J., Wang, J., Yarnitzky, C., (1995) Electroanalysis, 7, p. 79Hernández, L., Zapardiel, A., Pérez-Lópes, J.A., Bermejo, E., (1987) Anal. Chim. Acta, 198, p. 239Visalakshi, G., Narasimhan, S.V., Venkateswarlu, K.S., (1988) Anal. Chim. Acta, 212, p. 335Bond, A.M., Pfund, B.V., (1993) Anal. Chim. Acta, 277, p. 145Bharatibai, J.B., Padma, D.K., Rajagopalan, S.R., (1994) Fresenius J. Anal. Chem., 349, p. 477Wang, S., Du, L., Bin Li, A.Z., (1997) Anal. Lett., 30, p. 2099Cox, J.A., Majda, M., (1980) Anal. Chim. Acta, 118, p. 271Van Den Berg, C.M.G., Huang, Z.Q., (1984) J. Electroanal. Chem., 177, p. 269Wang, J., Mahmoud, J., (1987) Fresenius Z. Anal. Chem., 327, p. 789Hua, C., Jagner, D., Renman, L., (1988) Talanta, 35, p. 597Gao, Z., Kok, S.S., (1996) Talanta, 43, p. 727El-Maali, N.A., Temerk, Y.M., El-Aziz, M.S.A., (1997) Anal. Chim. Acta, 353, p. 313Kolthoff, I.M., Lingane, J.J., (1965) Polarography, 2, p. 499. , Interscience Publishers, 2a edSouchay, P., Faucherre, J., (1949) Anal. Chim. Acta, 3, p. 259Riley, T., Watson, A., (1987) Polarography and Other Voltammetric Methods, p. 220. , John Wiley & Sons, ChichesterMiller, J.C., Miller, J.N., (1990) Statistics for Analytical Chemistry, pp. 115-117. , Ellis Horwood, Chichester, 3a edChristian, G.D., (1994) Analytical Chemistry, p. 10. , John Willey &ampSons, New York, 5a e