Oxidation and flow-injection amperometric determination of 5-hydroxytryptophan at an electrode modified by electrochemically assisted deposition of a sol-gel film with templated nanoscale pores

TALANTA

卷:82

Article

Ranganathan, David^1,2  Zamponi, Silvia²  Berrettoni, Mario^3,4  Mehdi, B. Layla¹  Cox, James A.¹ 

[1] Miami Univ, Dept Chem & Biochem, Oxford, OH 45056 USA

[2] Univ Camerino, Dept Chem Sci, I-62032 Camerino, Italy

[3] Univ Bologna, Dept Phys & Inorgan Chem, I-40136 Bologna, Italy

[4] INSTM Bologna, Unita Ric, I-40136 Bologna, Italy

关键词: Sol-gel films;    Electrochemically assisted deposition;    5-Hydroxytryptophan;    Voltammetry;    Flow-injection analysis;   

DOI  :  10.1016/j.talanta.2010.06.025

来源: Elsevier

【 摘 要 】

The oxidation of 5-hydroxytryptophan (5-HTPP) yielded a passivating polymeric film at an indium tin oxide (ITO) electrode. Coating ITO with a nanoscale sol-gel film with a mesoporous structure was shown to change the pathway of the chemical reaction coupled to the electron transfer. The sol-gel film was deposited by an electrochemically assisted process, and the mesoporosity was imparted by including generation-4 poly(amidoamine) dendrimer in the precursor solution. The dendrimer was removed subsequently with an atmospheric oxygen plasma. This electrode remained active during cyclic voltammetry and controlled potential electrolysis of 5-HTPP, which was attributed to dimer, rather than polymer, formation from the oxidation product. Mass spectrometry confirmed this hypothesis. The anodic current was limited by the electron-transfer kinetics. Modification of the so-gel film by inclusion of cobalt hexacyanoferrate, which catalyzes the oxidation, resulted in a diffusion-limited current. Determination of 5-HTPP by flow-injection amperometry had a detection limit of 17 nM. (C) 2010 Elsevier B.V. All rights reserved.

【 授权许可】

Free