Voltammetric peak separation of dopamine from uric acid in the presence of ascorbic acid at greater than ambient solution temperatures.
Peak overlap in voltammetry poses challenges for the quantitative analysis of electroactive species. Dopamine and uric acid are typically challenging to determine voltammetrically because of their very similar oxidation peak potentials. We report preliminary results of the use of a screen-printed carbon electrode for the determination of dopamine and uric acid in an electrolyte solution maintained above ambient temperatures. Higher temperatures resulted in dramatic shifting of the dopamine oxidation peak toward lower potentials, while the uric acid peak was essentially stationary. Ascorbic acid, an interference in voltammetric uric acid determinations, is effectively suppressed at higher temperatures. This resulted in a greater peak separation of dopamine from uric acid at higher temperatures, which is desirable for better peak integration. In addition, greater current responses for both species were recorded at higher temperatures. The cause for such an increase in peak current is unraveled using ac impedance measurements. Presented are preliminary results for determining dopamine and uric acid at temperatures higher than ambient. Much improved voltammetric peak separation and sensitivity is obtained at these higher temperatures compared to ambient.
Zen
Jyh-Myng
JM
Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan. jmzen@dragon.nchu.edu.tw
Hsu
Cheng-Teng
CT
Hsu
Yi-Lan
YL
Sue
Jun-Wei
JW
Conte
Eric D
ED
D001205:Ascorbic Acid / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D004298:Dopamine / Q000032:analysis* / Q000652:urine; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D006358:Hot Temperature; D006801:Humans; D014527:Uric Acid / Q000032:analysis* / Q000737:chemistry
D014527:Uric Acid; D002244:Carbon; D001205:Ascorbic Acid; D004298:Dopamine