Indirect amperometric detection of non-redox ions using a ferrocene-functionalized and oriented mesoporous silica thin film electrode. (20th February 2017)

• Record Type: Journal Article
• Authors: Karman, Cheryl; Vilà, Neus; Despas, Christelle; Walcarius, Alain
• Is Part Of: Electrochimica acta. Volume 228(2017)
• Page Start: 659
• Page End: 666
• Publication Date: 2017-02-20
• Subjects: Mesoporous silica film -- Ferrocene -- Redox-active modified electrodes -- Indirect amperometric detection -- Flow injection analysis -- Ion chromatography; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.01.126
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: Ferrocene-functionalized mesoporous silica films have been prepared on ITO electrodes. They can be used for indirect amperometric detection of non-electroactive anions. They can be applied in both flow injection analysis and suppressed ion chromatography. On-line regeneration is achievable by operating in square wave amperometry Abstract: Vertically oriented and ferrocene functionalized mesoporous silica thin films have been prepared by combining the electrochemically assisted self-assembly (EASA) method with click chemistry. The resulting films are electroactive, involving an electron hopping mechanism between adjacent ferrocene moieties. The electrochemical oxidation of ferrocene into ferricinium ion generates positive charges that are compensated by the ingress of anions into the film, opening the door to possible indirect amperometric detection of non-electroactive anions by flow injection analysis. Operating in an electrolyte-free flow, each injection of an anion (e.g., NO3 − ) at an electrode biased at a suitable positive potential (i.e., +0.5 V) gave rise to an amperometric response proportional to the anion concentration. However, to avoid the decrease of the electrochemical signal due to the progressive consumption of ferrocene in multiple successive analyses, it was necessary to regenerate the electrode by reduction of ferricinium moieties, which can be achieved in-situ by square wave amperometry. The feasibility to apply such indirect amperometric detection scheme in suppressed ion chromatography (for detecting anions in mixture) was also demonstrated.