Electrochemical Detection Of Ascorbic Acid Research Articles

Visible light photocatalytic degradation of crystal violet dye and electrochemical detection of ascorbic acid & glucose using BaWO4 nanorods

Barium tungstate (BaWO₄) rod like nanostructures were synthesized by slightly modified hydrothermal technique using sodium tungstate dihydrate (Na2WO₄. 2H2O) as tungstate ion source and barium nitrate [Ba(NO₃)₂] as barium ion source. The prepared nanostructures were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transform Infrared (FTIR) Spectroscopy.BaWO₄ nanorods were explored for their photocatalytic activity through decomposition of crystal violet (CV) dye under visible light under different pH conditions (acidic to basic) from 2 to 12. It was observed that BaWO₄ completely degrades CV within 60 min at highest pH of 12. BaWO₄ nanorods were also investigated for electrochemical detection of important analytes such as glucose and ascorbic acid using cyclic voltammetric technique. These studies exhibit the potential of BaWO₄ nanostructures for applications in environmental sciences as well as biosensor areas.

Facile green synthesis of reduced graphene oxide/tin oxide composite for highly selective and ultra-sensitive detection of ascorbic acid

In this work, we report a novel, cost effective and environmental-friendly green synthesis method of reduced graphene oxide (rGO) – tin oxide (SnO2) composite using lemon extract by hydrothermal process for selective and ultra-sensitive electrochemical detection of ascorbic acid. The electrochemical behavior of ascorbic acid at the surface of rGO-SnO2 composite modified glassy carbon electrode (GCE) was investigated by cyclic voltammetry (CV) technique whilst ascorbic acid sensing was performed by using differential pulse voltammetry (DPV) technique. An excellent sensitivity of 1200 μA mM−1 cm−2 (R2 = 0.990) towards ascorbic acid in the wide dynamic range of 400 μM −1600 μM without any surface fouling effect was observed which is, to the best of our knowledge, ~1.6 folds higher than previously reported ascorbic acid sensors. The as-fabricated sensor exhibited lower limit of detection (38.7 μM), superior reproducibility and selectivity towards interfering species such as glucose, urea, uric acid and Na+ ions. This enhanced sensing ability was studied and discussed in terms of forward biased nano-Schottky barriers at the rGO-SnO2 interface. The sensor was successfully evaluated for the detection of ascorbic acid in the vitamin C tablets and to predict unknown concentrations of ascorbic acid in PBS solution. This ultrasensitive, binder free rGO–SnO2 composite based sensor can be used for a simple, low cost and voltammetric detection of ascorbic acid in clinical diagnostics, pharmaceutical and food industries.

Preparation of flake hexagonal BN and its application in electrochemical detection of ascorbic acid, dopamine and uric acid

Flake hexagonal boron nitride (h-BN) was synthesized combining low temperature combustion synthesis (LCS) and carbothermal reduction and nitridation methods. The obtained h-BN is characterized as amorphous and layered structure with high density defects and active surface groups. The electrochemical properties of the flake BN modified glassy carbon electrode were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). These results demonstrate this kind of novel electrodes exhibit excellent electrocatalytic activity and high selectivity for electrochemical detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The liner relationships between current intensities and concentrations are found to be 30–1000, 0.5–150 and 1–300 μM, with detection limits of 3.77, 0.02 and 0.15 μM for AA, DA and UA, respectively. The sensor also exhibits good anti-interference ability, high stability and reproducibility.

Visible light assisted photocatalytic degradation of crystal violet dye and electrochemical detection of ascorbic acid using a BiVO4/FeVO4 heterojunction composite.

A BiVO4/FeVO4 nanocomposite photocatalyst was successfully synthesized via a hydrothermal method. The prepared heterojunction photocatalyst was characterized physically and chemically using XRD, SEM, EDX, XPS, BET, FT-IR, Raman, UV-vis DRS, EPR and photoluminescence techniques. BiVO4/FeVO4 was explored for its photocatalytic activity by the decomposition of crystal violet (CV) organic dye under visible radiation. This experiment showed that BiVO4/FeVO4 at a ratio of 2 : 1 completely degrades CV within 60 min. In addition, BiVO4/FeVO4 was investigated for the electrochemical detection of the useful analyte ascorbic acid using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry techniques. This work reveals the potential of the BiVO4/FeVO4 nanocomposite for applications in environmental disciplines as well as in biosensing.

Epigallocatechin Gallate-Modified Graphite Paste Electrode for Simultaneous Detection of Redox-Active Biomolecules.

In this study, simultaneous electrochemical detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA) was performed using a modified graphite paste electrode (MGPE) with epigallocatechin gallate (EGCG) and green tea (GT) powder. It was shown that the anodic peak current increased in comparison with that of the graphite paste electrode (GPE) in the cyclic voltammograms. The optimal pH for simultaneous determination of a quaternary mixture of AA–DA–UA was determined to be pH 2. The anodic peak potentials for a mixture containing AA–DA–UA were well separated from each other. The catalytic peak currents obtained at the surface of the MGPE/EGCG were linearly dependent on the AA, DA, and UA concentrations up to 23, 14, and 14 µM, respectively. The detection limits for AA, DA, and UA were 190, 90, and 70 nM, respectively. The analytical performance of this sensor has been evaluated for simultaneous detection of AA, DA, and UA in real samples. Finally, a modified electrode was prepared using GT and used for simultaneous determination of AA, DA, and UA. Based on the results, MPGE/GT showed two oxidation peaks at 0.43 and 0.6 V for DA and UA, respectively, without any oxidation peak for AA. The calibration curves at the surface of MGPE/GT were linear up to 14 µM with a detection limit of 0.18 and 0.33 µM for DA and UA, respectively. MGPEs provide a promising platform for the future development of sensors for multiplexed electrochemical detection of clinically important analytes.

Photochemical one-pot synthesis of reduced graphene oxide/Prussian blue nanocomposite for simultaneous electrochemical detection of ascorbic acid, dopamine, and uric acid

Abstract The practical application of Prussian blue (PB) for sensors is still limited due to its electrochemical properties that are dependent on factors such as the low stability at pH close to 7.0, the size and the shape of the material. In this sense, we report a green and facile strategy for one-pot synthesis of reduced graphene oxide/Prussian blue nanocomposites via photochemical method for sensing application. In the proposed method, graphene oxide was reduced simultaneously with the formation of PB nanocubes with controllable size, using sodium nitroprusside as precursor. The nanocomposite is more stable and sensible to electro-reduction of H2O2 when compared to PB at pH 7.4. The observed behavior is due to the ability of graphene to anchor the nanocubes and facilitate the electron transfer between the electrode and PB. Moreover, we also investigated the performance of the nanocomposite for simultaneous detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The sensor presented limits of detection of 34.7 μmol L−1, 26.2 μmol L−1, 8.0 μmol L−1, for AA, DA, and UA, respectively.

Determination of ascorbic acid in serum samples by screen-printed carbon electrodes modified with gold nanoparticles

This paper shows the ability of simple modified screen-printed devices for the electrochemical detection of ascorbic acid in different samples, including serum samples. Even if the presence of uric acid does not greatly affect the analysis of ascorbic acid using screen-printed carbon electrodes modified by gold nanoparticles, dopamine must be considered an interferent. Thus, the joint determination of the three compounds has been set out using methods of multivariate calibration. The validated models, built by partial least squares regressions, have been used to determine the concentration of ascorbic acid, dopamine and uric acid of spiked serum samples, with successful results.

Voltammetric determination of ascorbic acid by using a disposable screen printed electrode modified with Cu(OH)2 nanorods

The authors describe a disposable non-enzymatic sensor for ascorbic acid (AA) that was obtained by modifying a screen printed electrode (SPE) with Cu(OH)2 nanorods (NRs). The NRs were synthesized by a wet chemical process which involves sequential addition of NH3 and NaOH to CuSO4 solution. NR formation was confirmed by thermogravimetric, spectroscopic, microscopic, and diffraction studies. The Cu(OH)2 NRs were mixed with carbon ink and printed onto an SPE. Electrochemical detection of AA was carried out at pH 7.4, at a typical voltage as low as 0 mV versus saturated calomel electrode with a scan rate of 100 mV/s, and is assumed to involve the chemical reduction of Cu(II) by AA followed by electrochemical oxidation of Cu(I). The sensor has a linear response in the 0.0125 to 10 mΜ AA concentration range. Response to AA is free from interference by urea, glucose, uric acid, dopamine, metal ions such as Fe2+, Zn2+ and Ni2+, NaCl, KCl and ethanol. It was applied to the determination of AA in a vitamin C tablet and in urine.

Boron and Nitrogen Doped Graphene via Microwave Exfoliation for Simultaneous Electrochemical Detection of Ascorbic Acid, Dopamine and Uric Acid

AbstractBoron and nitrogen doped graphenes show opposite effect on the electronic structure, one with electron withdrawing and another one with electron donating effects. It is of high importance to investigate the influence of B or N doping on biomarkers detection and compare it to non‐doped graphene. Here we show that B‐doped graphene shows significant enhancement in detection currents in the cyclic voltammetry of the above mentioned compounds.

Electrochemical Detection of Neurotransmitters Using Modified PEDOT Electrodes

This paper presents recent results from authors’ labs on the electrochemical detection of ascorbic acid (AA), serotonin (5-HT) and dopamine (DA) at poly[3,4-ethylenedioxythiophene], PEDOT, and PEDOT-Au electrodes. We could show that the technique used for preparing the PEDOT and the PEDOT-Au electrodes strongly affects the quality of the sensors. Pulse plating gave the best films with regard to their morphology and charge storage. Parameters of the pulse sequence, such as anodic and cathodic potentials, as well as pulse duration, were optimized. Acoustic impedance data (obtained by an Electrochemical Quartz Crystal Microbalance in dispersive mode) show that such films prepared by pulse plating display also maximal elastic storage and loss moduli. The detection limits for the above mentioned neurotransmitters were studied by differential pulse voltammetry in phosphate buffer solution, PBS (Fig. 1), in the presence and absence of AA. Compared to pristine PEDOT, the Au modified electrodes showed a considerable increase of sensitivity and selectivity for neurotransmitters detection. Fig. 1. The DPV curves measured in PBS with different concentrations of (a) 5-HT and (b) DA, on PEDOT layers in the presence of 300μM AA Figure 1

A glassy carbon electrode modified with MoS2 nanosheets and poly(3,4-ethylenedioxythiophene) for simultaneous electrochemical detection of ascorbic acid, dopamine and uric acid

We describe a chemical exfoliation method for the preparation of MoS2 nanosheets. The nanosheets were incorporated into poly(3,4-ethylenedioxythiophene) (PEDOT) by electrodeposition on a glassy carbon electrode (GCE) to form a nanocomposite. The modified GCE is shown to enable simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Due to the synergistic effect of MoS2 and PEDOT, this electrode displays better properties in terms of electrocatalytic oxidation of AA, DA and UA than pure PEDOT, which is illustrated by cyclic voltammetry and differential pulse voltammetry (DPV). Under optimum conditions and at pH 7.4, the respective sensitivities and best working potentials are as follows: AA: 1.20 A∙mM−1∙m−2, 30 mV; DA: 36.40 A∙mM−1∙m−2, 210 mV; UA: 105.17 A∙mM−1∙m−2, 350 mV. The calculated detection limits for AA, DA and UA are 5.83 μM, 0.52 μM and 0.95 μM, respectively. The modified electrode was applied to the detection of the three species in human urine samples and gave satisfactory results.

Analysis of ascorbic acid by electrochemical detection

A glassy carbon electrode (GCE) modified by copper-doped titanium dioxide nanoneedles has been fabricated and used for the electrochemical detection of ascorbic acid (AA) in KCl solution. Two pairs of peak currents on quasi-reversible electrochemical cyclic voltammogram peaks (cvps) are located at +0.16 V,–0.03 V (cvp 1 and cvp 2) and +0.01 V,–0.44 V (cvp 1′ and cvp 2′), respectively. The relationship between the peak current and AA concentration is linear in the concentration range from 0.0005 to 2 mM. There is also a linear relationship between the peak current and the scan rate. The detection limit is 0.37 μM and 0.25 μM for cvp 1 and cvp 2, respectively, at a signal-to-noise ratio of 3. A GCE modified by copper-doped titanium dioxide nanoneedles exhibts good stability and has promising characteristics for the detection of AA.

Electrochemical Detection of Ascorbic Acid with Aluminium Bismuthate Nanorods Modified Electrode

Electrochemical Detection of Ascorbic Acid with Aluminium Bismuthate Nanorods Modified Electrode

Enhanced Sensitivity for Electrochemical Detection Using Screen-Printed Diamond Electrodes via the Random Microelectrode Array Effect.

The electrochemical properties of screen-printed diamond electrodes with various insulating polyester (PES) resin binder/boron-doped diamond powder (BDDP) ratios were investigated for high sensitivity electrochemical detection. For PES/BDDP weight ratios in the range of 0.3-0.5, the BDDP-printed electrodes exhibited cyclic voltammetry (CV) characteristics for Fe(CN)6(3-/4-) that are typical of a planar electrode, whereas microelectrode-like characteristics with sigmoidal CV curves were observed for PES/BDDP ratios of 1.0-2.0. Cu elemental mapping images of copper-electrodeposited BDDP-printed electrodes indicated the formation of island structures with conductive BDDP domains surrounded by an insulating PES matrix for large PES/BDDP ratios. The electrochemical detection of ascorbic acid (AA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) was also investigated using polycrystalline BDD thin-film and BDDP-printed electrodes (PES/BDDP ratio = 0.3 and 1.0). As a result, the signal-to-background (S/B) ratios for the voltammetric detection of AA and 8-OHdG were in the order BDDP-printed electrode (PES/BDDP = 1.0) > BDDP-printed electrode (PES/BDDP = 0.3) > polycrystalline BDD thin film electrode, based on the large faradaic current with respect to the background current. Therefore, the BDDP-printed electrode with a large insulating binder/BDDP ratio has the potential for use as a disposable electrode for electrochemical detection. The electrode is cheaper, lighter and more sensitive than conventional BDD electrodes.

Rapid synthesis of hollow Ni(OH)2 with low-crystallinity for the electrochemical detection of ascorbic acid with high sensitivity

Ni(OH)2 performed good properties to ascorbic acid detection with the linear range of 10 μM to 0.20 mM, the detection limit of 3 μM (S/N = 3). The sensitivity is 1747.71 μA mM−1 cm−2, which is due to the hollow Ni(OH)2 with low crystallinity.

One-pot facile fabrication of graphene-zinc oxide composite and its enhanced sensitivity for simultaneous electrochemical detection of ascorbic acid, dopamine and uric acid

Reduced graphene oxide-zinc oxide (RGO–ZnO) composite was facilely fabricated by a spontaneous reduction of graphene oxide via zinc slice in one-pot approach at room temperature, and used to modify glassy carbon electrode (GCE) for developing of electrochemical biosensor (RGO–ZnO/GCE). The as-prepared RGO–ZnO was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM) and transmission electron microscope (TEM). It was revealed that the existence of ZnO in RGO–ZnO/GCE largely enhanced the electroactive surface area (EASA) and therefore the sensitivity for electrochemical sensing. In the mixtures of ascorbic acid (AA), dopamine (DA) and uric acid (UA), the biosensor exhibited three well-resolved voltammetric peaks (ΔEAA–DA=236mV, ΔEDA–UA=132mV, ΔEAA–UA=368mV) in the differential pulse voltammetry (DPV) measurements, allowing a simultaneous electrochemical detection of these biomolecules. The liner relationships between current intensities and concentrations were found to be 50–2350μM, 1–70μM and 3–330μM, with detection limits of 3.71μM, 0.33μM and 1.08μM for AA, UA and DA, respectively. The as-prepared RGO–ZnO/GCE biosensor displayed a good reproducibility and stability and was applied for detection of of AA, DA and UA in real plasma and urine samples with satisfying results.

An electrochemical biosensor based on cobalt nanoparticles synthesized in iron storage protein molecules to determine ascorbic acid.

The electrochemical detection of ascorbic acid (AA) was investigated using a cobalt(III)-ferritin immobilized on a self-assembled monolayer modified gold electrode in phosphate buffer solution (pH7.5). The modified electrode showed excellent electrochemical activity for oxidation of AA. The response to AA on the modified electrode was examined using cyclic and differential pulse voltammetry techniques. The resulting biosensor showed a linear response to AA in a concentration range from 6.25×10-6 to 2.31×10-5 M with sensitivity of 86,437 μAM-1 and detection limit of 4.65 × 10-6 M based on a signal-to-noise ratio of 3. Electrochemical parameters including the charge transfer coefficient (α) and the apparent heterogeneous electron transfer rate constant (ks ) for AA were found to be 0.52 and 1.054 Sec-1 , respectively. It has been shown that, using this modified electrode, AA can be determined with high sensitivity, low detection limit, and high selectivity.

Preparation in-situ of carbon nanotubes/polyaniline modified electrode and application for ascorbic acid detection

A novel grown in-situ carbon nanotube/polyaniline chemically modified electrode (GSCNT/PANI-CME) was synthesized for the electrochemical detection of ascorbic acid (AA). First, nickel catalyst was obtained by direct current electrochemical deposition on a graphite electrode (GE) surface. Second, CNTs were grown in-situ to obtain CNTs chemically modified electrode (GSCNTs-CME) by catalytic chemical vapor deposition. Third, the grown CNTs were acid treated to carboxylate and remove nickel particles. Finally, PANI was prepared in-situ by electrochemical polymerization on the GSCNTs-CME to obtain GSCNTs/PANI-CME. The obtained electrodes were characterized by scanning electron microscopy and cyclic voltammetry. The results showed that CNTs grew uniformly on the GE surface and the original tubular structure was remained. PANI was uniformly coated on the surface of CNTs in the obtained composite, which was a typical three-dimensional network structure. The GSCNTs/PANI-CME exhibited an excellent electrocatalytic activity to AA. The oxidation peak current was increased linearly with the concentration of AA in the range from 1.0×10−6molL−1 to 4.5×10−4molL−1, with a detection limit of 1.0×10−7molL−1 (S/N=3). The experimental data showed that the obtained electrode was selective, stable and reproducible. The recoveries were between 97.4% and 102.1%.

Biomass-derived functional porous carbons as novel electrode material for the practical detection of biomolecules in human serum and snail hemolymph.

The biomass-derived activated carbons (ACs) have been prepared with high surface areas up to 793 m2 g−1 is by ZnCl2 activation at three different temperatures, viz. AC700, AC800, and AC900. The AC samples were characterized by a variety of analytical and spectroscopy techniques. The as-synthesized ACs were adopted for the simultaneous electrochemical detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). For comparison, reduced graphene oxide (RGO) was employed for the proposed sensor. The high surface area, modulated pore size and the presence of oxygen surface functional groups like heteroatoms (83.427% C, 1.085% N, 0.383% S, and 0.861% H) in the biomass-derived AC is found to be responsible for the excellent catalytic activities of biomolecules. Fascinatingly, the facile sensor further used to detect biomolecules levels in the snail hemolymph and human blood serum. Notably, the obtained analytical parameters for the biomolecules detection over the AC modified GCE, outperforming several carbon-based modified electrodes in literatures.

Selective electrochemical detection of ascorbic acid in canned juice using aniline/N-(1-naphthyl)ethylene-diamine modified MWCNT electrode

Selective electrochemical detection of ascorbic acid in canned juice using aniline/N-(1-naphthyl)ethylene-diamine modified MWCNT electrode