Selective Detection of Dopamine and Its Metabolite, DOPAC, in the Presence of Ascorbic Acid Using Diamond Electrode Modified by the Polymer Film

Abstract

The surface of boron-doped diamond (BDD) electrode is modified by the polymer film for the first time. The cationic polymer film of N,N-dimethylaniline (DMA) is electrochemically deposited on BDD electrode surface. This polymer (PDMA) film-coated BDD electrode is used as a sensor which selectively detect dopamine (DA) in the presence of ascorbic acid (AA). This electrode also can detect both DA and its metabolite, 3,4-dihydroxy phenyl acetic acid (DOPAC) in the presence of AA in the range of the physiological concentrations of these species. Favorable ionic interaction (i.e., electrostatic attraction) between the PDMA film and AA or DOPAC lowers their oxidation potentials and enhances the current response for AA and DOPAC compared to that at the bare electrode. The PDMA film also shows a hydrophobic interaction with DA and DOPAC. In cyclic voltammetric measurements, the PDMA film-coated electrode can successfully separate the oxidation potentials for AA and DA coexisting in the same solution and the separation is about 200 mV. AA oxidizes at more negative potential than DA. In square-wave voltammetry, the sensitivity of the PDMA film-coated BDD electrode for DA in the presence of higher concentration of AA is higher than that of the PDMA film-coated glassy carbon electrode. The hydrodynamic amperometric experiments confirm that the oxidation of AA is not affected by the oxidized product of DA and vice versa. So, unlike the bare electrode the catalytic oxidation of AA by the oxidized DA is eliminated at the PDMA film-coated BDD electrode. The sensitivities of the modified electrode for AA, DA and DOPAC, which are present in the same solution with their physiological concentration ratios, are calculated to be 0.070, 0.363 and 0.084 mA mM À1 , respectively. The modified electrode exhibits a stable and sensitive response to DA.

Dopamine Sensor Based on a Boron-Doped Diamond Electrode Modified with a Polyaniline/Au Nanocomposites in the Presence of Ascorbic Acid

“…The sensor performances of the modified BDD electrodes reported in the literature for determination of DA are compared in Table 1. 7,9,20,25 As shown in Table 1, many sensors had a low sensitivity, narrow linear ranges, and a high detection limit. Although the PDMA film-coated BDD electrode has a higher sensitivity than our electrode, its linear range was very narrow.…”

“…4,5 Hence, both sensitivity and selectivity are very important factors in developing a DA sensor. Some approaches have been proposed for modifying the electrode surface by utilizing various materials or techniques, such as ion-exchange polymers, [6][7][8] inorganic materials, 9 carbon materials, 6 and self-assembled monolayers. 5,10 Boron-doped diamond (BDD) film has attracted considerable interest for use as active electrodes due to its superior chemical, physical, mechanical inertness and unique optical properties.…”

Sensitive and Selective Detection of Dopamine Using a DNA Immobilized Ethylenedidamine/Polyglutamic Modified Electrode

“…The construction of DNA sensors can be formed by either direct absorption or covalent bond of DNA on the top of polymer layer [14][15][16][17]. Although, some papers have reported the determination of neurotransmitter using polymer modified electrodes [18][19][20], limited attention has been towards to the application of this layer-bylayer modified DNA and conducting polymers biosensors for the determination of neurotransmitter. In this work, a voltammetric sensor was fabricated by depositing a layer of DNA onto ethylenediamine (En), which was covalent bonded on a previous polyglutamic acid (PGA) modified glass carbon electrode (GCE) (DNA/En/PGA/GCE).…”

Electrochemical behaviour of dopamine at covalent modified glassy carbon electrode with l-cysteine: preliminary results

“…Electrochemical techniques have attracted great interest in many cases, and these techniques can be fast in detection, low in cost, and with the merits of low detection limit and high accuracy. The cyclic voltammetric response for DA has been studied at a variety of modified electrode surfaces [13][14][15][16][17][18][19][20][21][22][23] . In recent years, carbon nanotubes have been widely used as electrochemical sensors and biosensors 24 .…”