Abstract
It is found that cysteine and methionine quantitatively react with electrogenerated halogens under the conditions of galvanostatic coulometry. Cysteine reacts with all titrants, and methionine reacts only with chlorine and bromine. The stoichiometric coefficients of reactions between cysteine and halogens are 1:3, 1:3, and 1:1 for chlorine, bromine, and iodine, respectively. These coefficients for methionine reactions with chlorine and bromine are 1:2 and 1:1, respectively. It is shown that cysteine can be selectively determined in its mixtures with methionine by coulometric titration with electrogenerated iodine. It is found that twofold amounts of methionine do not interfere with the determination of cysteine. A procedure is developed for the direct coulometric determination of methionine in tablets with a relative standard deviation of 3–5%.
Similar content being viewed by others
References
Elad, D. and Ginsburg, D., J. Am. Chem. Soc., 1954, vol. 76, no. 1, p. 312.
Huang, T.H., Kuwana, T., and Warsinke, A., Biosens. Bioelectron, 2002, vol. 17, nos. 11–12, p. 1107.
Stone, C.G., Cardosi, M.F., and Davis, J., Anal. Chim. Acta, 2003, vol. 491, no. 2, p. 203.
Shaidarova, L.G., Ziganshina, S.A., Tikhonova, L.N., and Budnikov, G.K., Zh. Anal. Khim., 2003, vol. 58, no. 12, p. 1277 [J. Anal. Chem. (Engl. Transl.), vol. 58, no. 12, p. 1144].
Bakhsh, R.J., Reza, O., and Mansoure, K., Bull. Chem. Soc. Jpn., 2005, vol. 78, no. 5, p. 818.
Perez-Ruiz, T., Martinez-Lozano, C., Tomas, V., and Martin, J., Talanta, 2002, vol. 58, no. 5, p. 987.
Nie, L., Ma, H., Sun, M., Li, X., Su, M., and Liang, S., Talanta, 2003, vol. 59, no. 5, p. 959.
Tanaka, F., Mase, N., and Barbas, C.F., Chem. Commun., 2004, no. 15, p. 1762.
Chwatko, G. and Bald, E., Talanta, 2000, vol. 52, no. 3, p. 509.
Song, Z., Fang, H., Jianwei, Z., Lijing, W., Feng, Z., and Pengyuan, Y., Talanta, 2002, vol. 58, no. 3, p. 451.
Ohmori, S., Kawaseb, T., Higashiurab, M., Chisakab, Y., Nakatab, K., and Yabasakic, Y., J. Chromatogr. B, 2001, vol. 762, no. 1, p. 25.
Wuilloud, R.G., Kannamkumarath, S.S., Wuilloud, J.C.A., and Caruso, J.A., ICP Inf. Newsl., 2003, vol. 29, no. 6, p. 525.
Budnikov, G.K., Ziyatdinova, G.K., and Valitova, Ya.R., Zh. Anal. Khim., 2004, vol. 59, no. 6, p. 645 [J. Anal. Chem. (Engl. Transl.), vol. 59, no. 6, p. 573].
Sharaf, M.A., Illman, D.L., and Kowalski, B.R., Chemometrics, New York: Wiley, 1986.
Author information
Authors and Affiliations
Additional information
Original Russian Text © G.K. Ziyatdinova, L.V. Grigor’eva, G.K. Budnikov, 2007, published in Zhurnal Analiticheskoi Khimii, 2007, Vol. 62, No. 12, pp. 1304–1308.
Rights and permissions
About this article
Cite this article
Ziyatdinova, G.K., Grigor’eva, L.V. & Budnikov, G.K. Coulometric determination of sulfur-containing amino acids using halogens as oxidizing titrants. J Anal Chem 62, 1176–1179 (2007). https://doi.org/10.1134/S1061934807120143
Received:
Issue Date:
DOI: https://doi.org/10.1134/S1061934807120143