Ion exchange voltammetry at branched polyethylenimine cross-linked with ethylene glycol diglycidyl ether and sensitive determination of ascorbic acid

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• 作者：Vellaichamy Ganesan ; Pankaj Kumar Rastogi ; Rupali Gupta ; Matthew T. Meredith ; Shelley D. Minteer
• 关键词：Ion exchange voltammetry ; Polymer modified electrodes ; Ascorbic acid oxidation ; Electrocatalysis
• 刊名：Electrochimica Acta
• 出版年：2013
• 出版时间：30 August, 2013
• 年：2013
• 卷：105
• 期：Complete
• 页码：31-39
• 全文大小：1496 K

文摘

The construction and characterization of an electrochemical sensing platform based on a cationic polymer modified electrode are described in this work. The cationic polymer is prepared as a thin film on a glassy carbon electrode (GC) surface by in situ cross-linking of branched polyethylenimine (BPEI) with ethylene glycol diglycidyl ether (EGDE). Positively charged amino groups of this polymer (BPEI-EGDE) act as effective anion exchange groups. The ion exchange properties of BPEI-EGDE are investigated by determining the permeability of electroactive anions through the polymer film using cyclic voltammetry. Furthermore, the modified electrodes are used for the electrochemical detection of ascorbic acid (AA), which is feasible with the films alone or when hexacyanoferrate ([Fe(CN)₆]^4?), is electrostatically confined (by ion exchange) in the cationic BPEI-EGDE film. When compared with bare GC electrodes, a large decrease in AA oxidation overpotential is observed at the [Fe(CN)₆]^4?-modified electrode surface. Kinetic parameters of electrocatalytic oxidation of AA by electrogenerated [Fe(CN)₆]^3? are evaluated by cyclic voltammetry and chronoamperometry. Finally, this method is employed for the determination of AA in a pharmaceutical tablet.