caa a22 4500 463219368 CHVBK 20180405153207.0 cr unu---uuuuu 170326e20071201xx s 000 0 eng 10.1134/S1061934807120143 doi (NATIONALLICENCE)springer-10.1134/S1061934807120143 Coulometric determination of sulfur-containing amino acids using halogens as oxidizing titrants [Elektronische Daten] [G. Ziyatdinova, L. Grigor'eva, G. Budnikov] 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%. Pleiades Publishing, Ltd., 2007 Ziyatdinova G. Butlerov Institute of Chemistry, Kazan State University, ul. Kremlevskaya 18, 420008, Kazan, Tatarstan, Russia aut Grigor'eva L. Butlerov Institute of Chemistry, Kazan State University, ul. Kremlevskaya 18, 420008, Kazan, Tatarstan, Russia aut Budnikov G. Butlerov Institute of Chemistry, Kazan State University, ul. Kremlevskaya 18, 420008, Kazan, Tatarstan, Russia aut Journal of Analytical Chemistry Nauka/Interperiodica 62/12(2007-12-01), 1176-1179 1061-9348 62:12<1176 2007 62 10809 https://doi.org/10.1134/S1061934807120143 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1134/S1061934807120143 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ziyatdinova G. Butlerov Institute of Chemistry, Kazan State University, ul. Kremlevskaya 18, 420008, Kazan, Tatarstan, Russia aut NATIONALLICENCE 700 1- Grigor'eva L. Butlerov Institute of Chemistry, Kazan State University, ul. Kremlevskaya 18, 420008, Kazan, Tatarstan, Russia aut NATIONALLICENCE 700 1- Budnikov G. Butlerov Institute of Chemistry, Kazan State University, ul. Kremlevskaya 18, 420008, Kazan, Tatarstan, Russia aut NATIONALLICENCE 773 0- Journal of Analytical Chemistry Nauka/Interperiodica 62/12(2007-12-01), 1176-1179 1061-9348 62:12<1176 2007 62 10809 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer