Poly-xanthurenic acid modified electrodes: An amperometric sensor for the simultaneous determination of ascorbic and uric acids

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• 作者：Francisco de Assis dos Santos Silva^a ; ^d  ; [Author Vitae] ; Cleylton Bezerra Lopes^a ; ^b ; ^d  ; [Author Vitae] ; Lauro Tatsuo Kubota^c ; ^d  ; [Author Vitae] ; Phabyanno Rodrigues Lima^a ; ^b ; ^d ; ^{phabyanno.lima@ifal.edu.br}  ; [Author Vitae] ; Marí ; lia Oliveira Fonseca Goulart^a ; ^d ; ^{mofg@qui.ufal.br} ; ^{mariliaofg@gmail.com}  ; [Author Vitae]
• 关键词：Xanthurenic acid ; MWCNT ; Ascorbic acid ; Uric acid ; Electrocatalysis ; Chemically modified electrodes
• 刊名：Sensors and Actuators B ; Chemical
• 出版年：2012
• 期刊代码：161_09254005
• 类别：et
• 出版时间：20 June, 2012
• 卷：168
• 期：Complete
• 页码：289-296
• 文件大小：558 K

摘要

The poly-xanthurenic acid (poly-Xa)/multi-walled carbon nanotube (MWCNT)/glassy carbon modified electrode (poly-Xa/MWCNT/GCE) was successfully applied for the simultaneous determination of ascorbic (AA) and uric (UA) acids. Cyclic voltammetric results show that the modified electrode displays an excellent eletrocatalytic activity toward the oxidation of AA at a low potential (0.05 V m>versusm> Ag/AgCl) and anodic peak resolution (螖m>Em>_pa), close to 300 mV m>versusm> Ag/AgCl, in solutions containing AA and UA. Values in the order of 10⁶ L mol^鈭? s^鈭? were obtained for the kinetic constant m>km>_cat for the catalytic oxidation of AA, upon evaluation by cyclic voltammetry, chronoamperometry and RDE. Furthermore, the sensor provided limits of detection of 0.19 渭mol L^鈭? and 0.31 渭mol L^鈭? for AA and UA, respectively. The sensor was applied for the simultaneous determination of AA and UA in urine samples and the average recoveries for these samples were 99.9 (卤2.5)%and 99.9 (卤2.6)%, respectively.