Electroanalysis Of Dopamine Research Articles

A Sensor for Selective Dopamine Determination Based on Overoxidized Poly‐1,5‐Diaminonaphthalene on Graphene Nanosheets

AbstractAn effective nanocomposite sensor for selective electroanalytical dopamine (DA) determination using overoxidized conducting polymer of poly‐1,5‐diaminonaphthalene (OPoly‐1,5‐DAN) functionalized graphene nanosheets (GNS) was achieved. The OPoly‐1,5‐DAN/GNS nanocomposite polymer was prepared via an electropolymerization of 1,5‐DAN on GNS/GCE after 7 cycles of potential scan (−0.2 V to +0.9 V), followed by an electrooveroxidation of the nanocomposite Poly‐1,5‐DAN/GNS by the potential cycle (0.0 V to +1.8 V) for 2 scans. The OPoly‐1,5‐DAN was effectively designed by GNS as a uniformly distribution of nanocomposite that caused more accumulations of analyte due to large electrocatalytic active positions created on electrode surface. The high specific and sensitive performance of the OPoly‐1,5‐DAN/GNS nanocomposite polymer was conducted to greater effective electrons transferring behavior for DA with copresent of vitamin C (VC). The stable and suitable formation of OPoly‐1,5‐DAN/GNS nanocomposite polymer showed rapid charge transport voltammogram and obvious electrocatalytic activity to DA and eliminated VC response. Moreover, the OPoly‐1,5‐DAN/GNS displays an excellent responses to DA determination with wide linear range (LR) 1.0–150 μM and lower detection limit (DL) 8.82±0.1 nM as comparing with other studies. Additionally, the excellent reproducibility of OPoly‐1,5‐DAN/GNS as well as long‐term stability indicated that it is an excellent and effective electrochemical DA sensor. Finally, the electroanalytical application of the OPoly‐1,5‐DAN/GNS nanocomposite polymer was employed for the electroanalysis of DA in human urine.

Copper-silver bimetallic nanoelectrocatalyst on pencil graphite substrate for highly selective amperometric dopamine sensor

Herein we report preparation of copper-silver bimetallic nanostructures with excellent electrocatalytic properties. Copper nanostructures were formed by template electrodeposition method while bimetallic nanostructures were prepared by galvanic replacement of copper with silver. Electrocatalytic activity of these nanocatalysts were demonstrated using electroanalysis of dopamine as model analyte. A maximum sensitivity of 1.56 μA/μM/cm2 and a lower limit of detection of 26 nM together with good recovery in real sample analysis provided the practical feasibility of the sensor. In summary, this work demonstrates a facile route for the fabrication of cost-effective bimetallic nanoelectrocatalysts under ambient conditions within a short duration of time.

Co/Co‐N@Nanoporous Carbon Derived from ZIF‐67: A Highly Sensitive and Selective Electrochemical Dopamine Sensor

AbstractCo/Co‐N nanoparticles incorporated nitrogen‐doped nanoporous carbon (Co/Co‐N@NPC) nanostructures were fabricated via pyrolysis of metal organic framework, ZIF‐67, under argon atmosphere. The ZIF‐67 derived Co/Co‐N@NPC modified carbon paste electrode exhibited excellent performance during electroanalysis of dopamine, displaying two linear ranges; 10 nM to 50 μM, and 50 μM–500 μM with sensitivity of 12.4±0.3 μA/μM/cm2 and11.69±0.06 μA/μM/cm2, respectively. The modified electrodes were observed to be highly selective towards dopamine even in presence of other interfering biomolecules such as ascorbic acid, glucose and uric acid. To the best of our knowledge, the sensing ability of Co/Co‐N@NPC with a lower limit of detection as 6 nM is the best compared to the previously reported cobalt mediated sensors for dopamine. Practical feasibility of the sensor was demonstrated in real sample analysis of dopamine measurement in human urine samples and dopamine hydrochloride injection samples.

Selective electrochemical determination of dopamine at p-nitroaniline film-hole modified glassy carbon electrodes

Herein, we report determination of dopamine (DA) at modified glassy carbon electrode (GCE) with a film produced by reduction of diazonium generated from p -nitroaniline (PNA). Pores were created purposely by stripping pre-deposited gold nanoparticles (AuNPs) in the modifier film. The modified electrodes were characterized electrochemically by common redox probes: hydroquinone (HQ), hexacyanoferrate [(Fe(CN)6)] 3- and hexamine ruthenium(III) [Ru(NH3)6] 3+ . Comparison was made for the cyclic voltammetric and amperometric response of DA using the modified electrodes against the bare GCE in phosphate buffer solution (PBS) of pH 7.5. The bare and modified GCE showed a linear response to DA in the concentration range of 0.2-2.2 mM and 5-35 µM with detection limit of 0.015 mM and 0.6112 µM, respectively. The modified electrode showed high sensitivity, well selectivity, good anti-interference ability, durable stability and good electrode reproducibility for determining DA. The reported modified electrode is a promising sensor for use in electroanalysis of DA. KEY WORDS : Diazonium, p -Nitroaniline, Gold nanoparticles, Dopamine, Ascorbic acid, Glassy carbon electrode Bull. Chem. Soc. Ethiop. 2017 , 31(3), 361-372 DOI: http://dx.doi.org/10.4314/bcse.v31i3.1

Electroanalysis of Dopamine Using Reduced Graphene Oxide-Palladium Nanocomposites

Electroanalysis of Dopamine Using Reduced Graphene Oxide-Palladium Nanocomposites

Sodium Dodecyl Sulphate/Poly(Brilliant Blue)/Multi Walled Carbon Nanotube Modified Carbon Paste Electrode for the Voltammetric Resolution of Dopamine in the Presence of Ascorbic Acid and Uric Acid

Sodium dodecyl sulphate/poly(brilliant blue)/multi walled carbon nanotube modified carbon paste electrode was fabricated for the electroanalysis of dopamine in the presence of ascorbic acid and uric acid in phosphate buffer solution of pH 7.4. The key parameters such as sensitivity, selectivity, antifouling property and stability were achievedby the modified electrode. The redox peaks obtained at modified electrode shows good electrocatalytic activity towards the oxidation of dopamine. From the effect of scan rateand concentration the electrode phenomenon was confirmed to be adsorption-controlled process. The lower limit of detection of dopamine was 2.69 × 10-7M, and the simultaneous analysis shows a good result with peak to peak separation between dopamine and other two analytes ascorbic acid and uric acid by both cyclic voltammetry and differential pulse voltammetric techniques.

Simultaneous Determination of Dopamine and L-Ascorbic Acid by Modified Carbon Paste Electrode with Ni (II) Cyclam Complex

The electroanalysis of dopamine (DA) and ascorbic acid (AA) by square wave voltammetry has been performed at a modified carbon paste electrode with macrocyclic ligand 1, 4, 8, 11-tetraazacyclotetradecane (cyclam) and monolayer of Ni (II) cyclam. In pH 7.2 buffer solutions, the electrostatic reaction of AA with di-positive monolayer shifts the oxidation potential to less positive potential, while the electrostatic repulsion of DA with the monolayer shifts the oxidation potential of DA to more positive potential. The separation between the oxidation peaks of AA and DA at the present di-positive monolayer modified electrode (252 mV) was larger than that (187 mV) at the cyclam modified electrode. In addition, the catalytic oxidation of AA by oxidized DA has been advantageously eliminated at the modified carbon paste electrode with cyclam and Ni (II) cyclam complex. Thus, the determination of DA in the presence of an excess of AA is possible with the present modified electrodes.

Self-assembled sulfonated β-Cyclodextrin layer on gold electrode for the selective electroanalysis of dopamine

Gold electrode with self-assembled D,L-cysteine grafted β-cyclodextrin sulfonic acid (Cys-β-CD∼SO3) layer was fabricated and used to investigate the electrochemical behavior of dopamine. The experimental results indicated that the self-assembled Cys-β-CD∼SO3 layer modified gold electrode has selective electrochemical response to dopamine with high sensitivity and excellent tolerance of ascorbic acid, which is the most common accompanying component in biological samples. Dopamine could be accurately determined in the concentration range of 1–200 μM in the presence of ascorbic acid of 5 mM. The relative standard deviation of 1.9% (n = 5) was achieved at a dopamine concentration of 5 × 10−5 M. The proposed sensor was successfully applied to the determination of dopamine in human blood serum samples.

Application of self-assembled ‘molecular wires’ monolayers for electroanalysis of dopamine

The selective electroanalysis of dopamine (DA) using the self-assembled monolayers of an oligo(phenyleneethynylene)s (OPEs) type molecular wire have been studied for the first time. Cyclic voltammetry measurement showed the OPE modified electrodes preferentially inhibit the electrochemical reaction of ascorbic acid (AA). Using square-wave voltammetry technique, DA was quantitatively determined in the presence of high concentration AA. This work reveals that, besides molecular electronics, biosensor could be an attractive new field of application for the OPE type molecular wires.

Electroanalysis of dopamine at a gold electrode modified with N-acetylcysteine self-assembled monolayer

Electroanalysis of dopamine at a gold electrode modified with N-acetylcysteine self-assembled monolayer

Electroanalysis of dopamine at a gold electrode modified with N-acetylcysteine self-assembled monolayer

Voltammetric behavior of dopamine (DA) on a gold electrode modified with the self-assembled monolayer (SAM) of N-acetylcysteine has been investigated, and one pair of well-defined redox peaks of dopamine is obtained at the SAM modified gold electrode. The oxidation peak current increases linearly with the concentration of dopamine in the range of 1.0×10−6to2.0×10−4moll−1. The detection limit is 8.0×10−7moll−1. This method will be applicable to the determination of dopamine in injection of dopamine hydrochloride, and the good recovery of dopamine is obtained. Furthermore, The SAM modified gold electrode can resolve well the voltammetric responses of dopamine and ascorbic acid (AA), so it can also be applied to the determination of dopamine in the presence of ascorbic acid.

Electroanalysis of dopamine and NADH at conductive diamond electrodes

Highly boron-doped diamond thin-film electrodes were examined for various possible applications in electroanalysis. Electrochemical oxidation of dopamine and NADH was investigated using cyclic voltammetry and chronoamperometry. Comparison experiments were performed using glassy carbon electrodes. Anodically treated diamond electrodes made it possible to determine dopamine selectively with high sensitivity in the presence of a large excess of ascorbic acid in acidic media. A detection limit of 50 nM was obtained using chronoamperometry. The treated electrodes were found to be stable for several months. Electrochemical oxidation of NADH was carried out at as-deposited diamond electrodes, with which very stable and reproducible cyclic voltammograms for NADH oxidation were obtained, unlike glassy carbon, at which a significant positive shift (∼200 mV) in the peak potential was observed within 1 h. The amperometric detection limit was found to be ∼10 nM. Interference of ascorbic acid was minimal using untreated electrodes when the concentration of ascorbic acid was comparable to the NADH concentration. Diamond microelectrodes small enough to consist of only one or two high quality microcrystals were fabricated in order to compare the electrochemical behavior with that of polycrystalline thin film electrodes, which contain large numbers of grain boundaries, at which non-diamond (sp2) carbon can exist. This work demonstrates the potential of diamond electrodes for electroanalytical applications.