The effect of cytosine on the two-step electroreduction of Zn 2+ ions in acetic buffers

• Published in: Electrochimica acta Vol. 51; no. 11; pp. 2278 - 2281
• Main Authors: Nieszporek, J., Gugała, D., Sieńko, D., Szaran, J., Saba, J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2006
• Subjects: Cytosine; Electroreduction of Zn 2+ ions; Inhibition; Kinetics of electrode process; Mercury electrode; Electroreduction of Zn 2+ ions; Kinetics of electrode process; Cytosine; Inhibition; Mercury electrode
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2005.03.079

Cytosine plays an important role in many biological processes since it constitutes the buildings blocks of DNA and RNA. A two-step reduction of Zn 2+ ions at the dropping mercury electrode in acetic buffers at pH 4 and 5 in the presence of cytosine was examined. The measurements were performed using an impedance method in a wide potential and frequency ranges. The values of the standard rate constants k s in the both studied system decrease from 3.8 × 10 −3 to 2 × 10 −3 cm s −1 at pH 4 and from 5.1 × 10 −3 to 2.5 × 10 −3 cm s −1 at pH 5. The values of the standard rate constants k s1 characterizing the stage of the first electron transfer decrease similarly. However, the values of the standard rate constants k s2 characterizing the stage of the second electron exchange decrease more markedly in the buffer at pH 4 than in the buffer at pH 5.