Voltammetric and Flow Injection Amperometric Determination of Cysteine at a Glassy Carbon Electrode in the Presence of Copper(II) Ions

Authors : Zekerya DURSUN, İlyas ŞAHBAZ, F Nil ERTAŞ, Gürel NİŞLİ

Pages : 513-520

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The voltammetric behaviour of cysteine was investigated in the presence of Cuinsert ignore into journalissuearticles values(II); ions at a rotating glassy carbon electrode insert ignore into journalissuearticles values(RGCE);. Two reduction peaks related to the successive reduction of the cysteine complexes of Cuinsert ignore into journalissuearticles values(II); and Cuinsert ignore into journalissuearticles values(I); ions were observed at --0.30 and --0.60 V vs. SCE respectively. These peaks were increased upon the addition of cysteine into a pH 9.20 borate buffer solution containing 0.1 M KNO3 and 1.0 x 10-5 M Cuinsert ignore into journalissuearticles values(II); ions. The calibration curve was linear in the concentration range of 5.0 x 10-10- 2.0 x 10-8 M for cysteine by utilising the peak current at --0.6 V vs. SCE. In the flow technique, 50 m L portions of off-line prepared mixtures of 1.0 x 10-5 M Cuinsert ignore into journalissuearticles values(II); and varying concentrations of cysteine were injected into the carrier solution of pH 9.20 borate buffer containing 0.1 M KNO3 flowing through 25 cm transmission tubing insert ignore into journalissuearticles values(i.d. 0.75 mm); at a rate of 1.5 mL/min. The signals were monitored at -- 0.60 V vs. SCE. The calibration graph was found to be linear in the concentration range 1.0 x 10-9 -- 1.0 x 10-7 M with a relative standard deviation of 1.0% insert ignore into journalissuearticles values(n = 5); for 5.0 x 10-8 M cysteine. The detection limit was calculated as 5 x 10-10 M for S/N = 3 ratio.
Keywords : Turk J Chem, 27, 2003, 513 520 Turk J Chem, vol 27, iss 4