Highly sensitive and selective electrochemical determination of dopamine and ascorbic acid at Ag/Ag2S modified electrode

✍ Scribed by Chen-Yan Li; Ying-Jie Cai; Chien-Hsin Yang; Chen-Hao Wu; Yen Wei; Ten-Chin Wen; Tzong-Liu Wang; Yeong-Tarng Shieh; Wen-Churng Lin; Wen-Janq Chen

• Book ID: 103828450
• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 324 KB
• Volume: 56
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2010.11.091

✦ Synopsis

A biosensor electrode possessing highly sensitive and selective determination of dopamine (DA) is fabricated. This electrode, a silver (Ag) thin film on indium-tin-oxide glass, is treated with a silver sulfide (Ag 2 S) film using electrochemical deposition. Active Ag ion is easier to form on Ag 2 S than on pristine Ag, which prefers to attract ascorbic acid (AA). The Ag 2 S layer reduces the oxidation potential of AA due to the electrostatic interaction, which results in well-separation of mixed oxidation responses to both of DA and AA. Besides, the Ag 2 S-modified electrode exhibits dramatic electrocatalytic effect on the oxidation of DA in the presence of AA. In 0.1 M phosphate buffer solution at pH ∼ 7.0, the differential pulse voltammetric peak intensity linearly correlates with DA concentration in two regions, viz. 1.0-10, and 10-100 M, with correlation coefficient of 0.998 and 0.995, respectively. The lowest concentration limit of 1.0 M DA can be detected. The interference of AA effectively diminishes in the mixed solution. These features make the Ag 2 S significant for selective and sensitive measurement of DA in the presence of excess AA.