Oxidation Potential Of Ascorbic Acid Research Articles

Facile fabrication of NaOH nanorods on pencil graphite electrode for simultaneous electrochemical detection of natural antioxidants by deep eutectic solvent

We report the application of deep eutectic solvents (DES) based on ethylene glycol and urea as low-cost, green, and suitable electrolytes for electrochemical studies. The main aim of this study was to explore the capabilities of DES as an enhancer of electrochemical detection for the natural antioxidants of ascorbic acid (AA) and gallic acid (GA). A simple fabrication of a disposable and effective electrochemical sensing platform for the simultaneous determination of AA and GA based on the one-step electrochemical deposition of NaOH nanorods on pencil graphite electrode (PGE) was performed. The electrochemical behavior showed that the two antioxidants, AA and GA, could be electro-oxidized and discriminated simultaneously on the surface of the NaOH/PGE. The oxidation potentials of AA and GA shifted slightly towards negative, and the peak current values increased 2.0-fold in DES than in BR buffer medium. Due to the strong synergistic effect between the nanostructures of NaOH (large effective surface area) and DES (high electrical conductivity), the proposed electrode led to the enhancement analytical performances towards AA and GA. Cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy were used to examine the modified electrode's morphological and electrochemical characterization and performance parameters. The developed sensor exhibited good performance towards the determination of AA and GA with a low detection limit (1.4 µM for AA and 0.6 µM for GA), wide linear concentration ranges (2–200 µM for AA and 1–30 µM for GA), and good reproducibility (1.4 % for AA and 0.4 % for GA). The effects of possible interferences were investigated for their effect on the determination of AA and GA. With good selectivity and sensitivity, the sensor's reliability for the simultaneous detection of AA and GA in mineral water (flavored with green tea and vitamin C) was successfully tested. The mean analytical recovery was 100.4 ± 2.5 and 96.2 ± 0.6 for AA and GA, respectively. The results obtained with the presented sensor were confirmed by the HPLC method. This is a promising approach for the determination of the detection of AA and GA in different water samples.

Effect of Power Density on the Electrochemical Properties of Undoped Amorphous Carbon (a‐C) Thin Films

AbstractUndoped a‐C thin films were deposited with varying power density from 10 to 25 W/cm2 using unbalanced closed‐field magnetron sputtering (CFUBMS). The effect of power density on the physical and electrochemical properties was investigated by experimental characterization methods and atomistic simulations. XPS indicated that the films were composed mostly of sp2‐bonded carbon (55–58 at.%) with a small amount of oxygen (8–9 at.%) in the surface region. The films appeared completely amorphous in XRD. The ID/IG ratio obtained by Raman spectroscopy indicated an increase from 1.76 to 2.34 with power density. The experimental and simulated data suggested a possible ordering and/or clustering of the sp2 phase with power density as the cause of the improved electrical properties of the a‐C films. The electrochemical properties of a‐C were between those of glassy carbon and tetrahedral amorphous carbon with potential windows ranging from 2.77 to 2.93 V and double‐layer capacitance values around 0.90 μF cm−2. Electron transfer for Ru(NH3)63+/2+ and FcMeOH+1/0 was reversible whereas that for IrCl62−/3− was quasi‐reversible. Peak potential separation of dopamine and oxidation potential of ascorbic acid decreased with power density, correlating with the structural and electrical changes of the films. The a‐C thin films deposited by CFUBMS are inherently conductive and their physical properties can be adjusted by varying the deposition parameters to a wide range of electrochemical applications.

Determination of Ascorbic Acid in <i>Citrus Sinensis</i> and <i>Ananas Comosus</i> Using Poly (3, 4-Ethylenedioxythiophene) Modified Glassy Carbon Electrode

This study describes the preparation and application of a poly (3, 4-Ethylenedioxythiophene) (PEDOT) modified glassy carbon electrode for ascorbic acid determination in fruit samples by square wave voltammetric method. The PEDOT modified electrode was prepared by electrochemical polymerizing of 3, 4-Ethylenedioxythiophene (EDOT) on a glassy carbon electrode in a non-aqueous medium (0.1 M Tetrabutylammoniumhexafluorophosphate and 0.1 M EDOT in acetonitrile). The best performance of the PEDOT modified electrode in 0.1 M phosphate buffer was obtained at pH 5.0. In addition to this other parameters like electrode thickness, square wave amplitude, and square wave frequency were optimized. Under these conditions, an oxidation potential of ascorbic acid was observed at 395.24 mV versus Ag/AgCl/ reference electrode. The square wave voltammetric study indicated that the PEDOT modified electrode showed a very good electrocatalytic activity by reducing the overpotential by 113.69 mV for ascorbic acid oxidation. The modified electrode also showed a linear response range between 50 and 90μM. The proposed method was checked by determining the recovery of ascorbic acid in two commercially available tablets and provided an excellent recovery (i.e. 99.43 and 93.80%). Finally the method was applied in Orange and Pineapple fruits and 68.11±0.012 and 45.46±0.023 mg ascorbic acid per 100 g of the sample was found in each fruits respectively.

Plasma-assisted synthesis of carbon fibers/ZnO core–shell hybrids on carbon fiber templates for detection of ascorbic acid and uric acid

Carbon fibers/ZnO core–shell hybrids were synthesized in this study by plasma-assisted strategy using carbon fiber templates. The hybrids were characterized by scanning electron microscopy and X-ray diffraction which revealed that the ZnO hybrids were attached on the surface of the carbon nanofibers. The hybrids were used to fabricate microelectrodes, exhibiting a strong electrocatalytic activity toward oxidation of ascorbic acid (AA) and uric acid (UA). Combination of the carbon fibers and ZnO largely increased the surface area of the electrodes, enhanced electron transfer on the electrode surface and widened the distance between oxidation potential of AA and UA. The hybrids therefore endowed the microelectrodes with portability, stability, higher selectivity and sensitivity. A biosensor was thus developed for detection of AA and UA concerning the above properties. The linear range for the AA and UA were 600–2000μM and 20–200μM, respectively. This work provides a portable and green route for constructing the biomedical sensor with promising prospect for clinical diagnosis.

Electrodeposition of palladium nanoparticles on porous graphitized carbon monolith modified carbon paste electrode for simultaneous enhanced determination of ascorbic acid and uric acid

A novel, simple and highly sensitive electrochemical method is developed for the determination of ascorbic acid (AA) and uric acid (UA) based on a palladium nanoparticles deposited on porous graphitized carbon monolith modified carbon paste electrode (PdNPs/CM/CPE). The chemical modified electrode was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The PdNPs/CM/CPE displayed excellent electrochemical catalytic activities toward AA and UA with bare CPE, PdNPs/CPE, CM/CPE and PdNPs/CM/CPE by cyclic voltammetry (CV). The oxidation potentials of AA and UA at the PdNPs/CM/CPE shifted negatively and the peak currents were much larger than other electrodes. The amperometric signal of PdNPs/CM/CPE showed a good linearity with correlation coefficient greater than 0.997. The low detection limits (S/N=3) for AA and UA were 0.53μmolL−1 and 0.66μmolL−1, respectively. The proposed method showed easy fabrication, high sensitivity and stability, and good reproducibility. In addition, the modified electrode was applied to determine the AA and UA in human serum sample.

Resolution of Dopamine in the Presence of Ascorbic Acid and Uric Acid by the Poly Oxalic Acid Modified Carbon Paste Electrode

A novel poly oxalic acid carbon paste electrode was fabricated by electro polymerization process and characterized in this study. This poly oxalic acid modified carbon paste electrode by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) exhibited an excellent electro catalytic activity towards the resolution of ascorbic acid (AA), dopamine (DA) and uric acid (UA) compared with bare carbon paste electrode. The effect of pH range from 5.5 to 8.0 was studied and the redox peak was pH dependent with a slope of 60 mV/pH and from the regression coefficient of the effect of scan rate shows that the process is adsorption controlled. The DPV study of 6.2 to 131 μM concentration range of DA shows 6 µM detection limit. The oxidation potentials of AA, DA and UA at the poly oxalic acid modified carbon paste electrode was shifted slightly negatively and the peak currents were much larger than the bare carbon paste electrode. DPV was used for the simultaneous determination of AA, DA and UA in their mixture, and the peak potential separations between AA and DA, DA and UA, AA and UA were197 mV, 169 mV and 367 mV respectively. The limit of detection for AA, DA and UA were 0.93 mM, 7.4 µM and13 µM respectively. This Oxalic acid modified carbon paste electrode showed many merits in stability, sensitivity, facility, economy and also applicable for real sample analysis.

Simultaneous Determination of Ascorbic Acid, Dopamine and Uric Acid, at a Graphene Paste Electrode Modified with Functionalized Graphene Sheets

The present study reports the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) in phosphate buffer solution (pH 7.0) using graphene paste electrode modified with functionalized graphene sheets (GPE-MFGSs). The presence of FGS inhibited the adsorption of AA owing to the electrostatic repulsion, but was favorable for the affinity adsorption of DA and UA via the ion exchange and hydrogen bonding mechanisms, respectively. This led to the decrease in the oxidation potential of AA and the significantly enhanced oxidation peak currents of DA and UA at the GPE-MFGSs. By cyclic voltammetry and differential pulse voltammetry, the oxidation potentials of AA, DA, and UA, at the GPE-MFGSs in a ternary mixture were found to be well resolved so that their simultaneous determination could be achieved. Furthermore, the influence of some experimental variables such as graphene paste composition, working solution pH, scan rate and pulse amplitude was studied. In addition, by differential pulse voltammetry, the linear dependence of peak current on the concentration was obtained in the ranges of 0.05–9.0, 0.03–13, and 0.03–5.5 µM with the lowest detection limits of 0.02, 0.01, and 0.01 µM for AA, DAand UA, , respectively.

Design of a nanostructured electromagnetic polyaniline–keggin iron–clay composite modified electrochemical sensor for the nanomolar detection of ascorbic acid

ABSTRACTThis article demonstrates the design and fabrication of an electrochemical sensor based on a platinum electrode for ascorbic acid (AA) modified by an electromagnetic polyaniline–Keggin iron–clay (PPICS) composite. The polyaniline–polyhydroxy iron–clay composite was prepared by the polymerization of [Anilinium]+[PDPSA]− in the presence of Keggin iron intercalated clay and was characterized for its particle size, morphology, electrical conductivity, and saturation magnetization. The oxidation potential of AA was observed at +0.4 V on the bare electrode and shifted to a negative potential of −0.32 V on the modified electrode. Common possible interferences of the sample matrices were tested, and the results reveal that the PPICS‐modified electrode exhibited a high selectivity and sensitivity toward AA. This unique low‐cost and user‐friendly sensor was validated for the nanomolar detection of AA present in real samples. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40936.

Electrochemical sensor based on carbon-supported NiCoO2 nanoparticles for selective detection of ascorbic acid

An electrochemical sensor for selective detection of ascorbic acid (AA) in the presence of dopamine (DA) and uric acid (UA) was fabricated by modifying the glassy carbon electrode (GCE) with carbon-supported NiCoO2 (NiCoO2/C) nanoparticles. The electrochemical impedance spectroscopic (EIS) studies reveal the little charge transfer resistance for the modified electrode. The electrocatalytic activity of the modified electrode for the oxidation of AA was investigated. The current sensitivity of AA was enhanced to about five times upon modification. The voltammetric response of AA was well resolved from the responses of DA and UA, and the oxidation potential of AA was negatively shifted to −0.20V. The biosensor tolerated a wide linear concentration range for AA, from 1.0×10−5M to 2.63×10−3M (R2=0.9929), with a detection limit of 0.5μM (S/N=3). Our results demonstrate that the NiCoO2/C nanomaterials has excellent AA sensing capability, including a fast response time, high reproducibility and stability, with great promise in the quantification of AA in real samples. That makes it a unique electrochemical sensor for the detection of AA which is free from the interference of DA, UA and other interferents.

Effects of reaction parameters on the preparation of submicron Cu particles by liquid phase reduction method and the study of reaction mechanism

Abstract Submicron Cu particles were prepared by reducing Cu 2 + ions with ascorbic acid via liquid phase reduction method. The oxidation potential of ascorbic acid (C 6 H 8 O 6 ) was measured to evaluate the feasibility of the redox reaction at different pH. Ascorbic acid was able to reduce the Cu 2 + to Cu particles when the solution pH varied between 3 and 7. The effects of the reaction parameters, including the solution pH, the concentration of PVP (polyvinylpyrrolidone) and Cu 2 + , on the preparation of Cu particles were also investigated. The reaction path varied with the solution pH. Cu particles could be directly reduced from Cu 2 + at pH 3, whereas they are reduced through Cu 2 O at pH 5 or 7. PVP was effective in inhibiting the agglomeration of Cu particles through steric effect.

Simultaneous electrochemical determination of ascorbic acid, dopamine and uric acid using a palladium nanoparticle/graphene/chitosan modified electrode

A palladium nanoparticle/graphene/chitosan/glassy carbon electrode (PdNPs/GR/CS GCE) was prepared and characterized in this paper. This chemical modified electrode displayed excellent eletrochemical catalytic activities towards ascorbic acid (AA), dopamine (DA) and uric acid (UA) compared with bare GCE, PdNPs/GCE and GR/CS GCE by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). All oxidation potentials of AA, DA and UA at the PdNPs/GR/CS GCE shifted negatively and the peak currents were much larger than other electrodes. DPV was used for simultaneous determination of AA, DA and UA in their mixture, and the peak potential separations between AA and DA, DA and UA, AA and UA were 252mV, 144mV and 396mV, respectively. The limits of detection (S/N=3) for AA, DA and UA were 20μM, 0.1μM and 0.17μM, respectively. This PdNPs/GR/CS GCE showed many merits in stability, sensitivity, facility and economy.

An electrochemical biosensor for ascorbic acid based on carbon-supported PdNinanoparticles

Carbon-supported PdNi nanoparticles (PdNi/C) were synthesized using a novel synthetic route, and characterized by transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The overall metallic content (Pd+Ni) was 10% (w/w) and uniformly distributed in the carbon black (90%) matrix. The electrocatalytic performance of the PdNi/C modified glassy carbon electrode (GCE) was investigated for ascorbic acid (AA) oxidation, and showed better catalytic activity than an equal amount of commercially available palladium carbon catalyst. The oxidation potential of AA was negatively shifted to −0.05V. The biosensor tolerated a wide linear concentration range for AA, from 1.0×10−5M to 1.8×10−3M (R=0.9973), with a detection limit of 0.5μM (S/N=3). Our results demonstrate that PdNi/C nanomaterials have excellent AA sensing capability, including a fast response time, high reproducibility and stability, with great promise in the quantification of AA in real samples. These qualities make the Pd-based bimetallic catalysts promising candidates for amperometric sensing.

An electrochemical biosensor for determination of ascorbic acid by cobalt (II) phthalocyanine–multi-walled carbon nanotubes modified glassy carbon electrode

Cobalt (II) phthalocyanine–multi-walled carbon nanotubes (CoPc–MWNTs) were synthesized and characterized by energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The cobalt (II) phthalocyanine–multi-walled carbon nanotubes modified glassy carbon (CoPc–MWNTs/GC) electrode was prepared using the drop coating method. The electrocatalytic performance of the chemically modified electrode was investigated for ascorbic acid (AA) oxidation. Our results demonstrate that the modified electrode has excellent electrocatalytic activity towards the oxidation of AA in 0.1 M phosphate buffer solution (PBS, pH 7.0). The oxidation potential of AA was negatively shifted to 0.19 V [vs. saturated calomel electrode (SCE)]. The biosensor tolerated a wide linear concentration range for AA, from 1.0 × 10 −5 M to 2.6 × 10 −3 M ( R = 0.9991), with a detection limit of 1.0 × 10 −6 M (S/N = 3). The CoPc–MWNTs modified glassy carbon electrode has several excellent properties, including a fast response time, high reproducibility and stability.

Electrochemical Determination of Dopamine on a Glassy Carbon Electrode Modified by Using Nanostructure Ruthenium Oxide Hexacyanoferrate/Ruthenium Hexacyanoferrate Thin Film

Application of mixed ruthenium oxide hexacyanoferrate/ruthenium hexacyanoferrate glassy carbon electrode for electrochemical determination of dopamine (DA) is described for the first time. The overlapped voltammetric oxidation potentials of ascorbic acid (AA) and DA are separated and shifted to more facile direction, +170 and +320 mV versus Ag/AgCl, respectively. Voltammetric response of the electrode toward the DA showed a dynamic calibration curve with two linear parts, from 0.50 to 10.00 μM and 25.00 to 550.00 μM DA, and a detection limit of 0.195 μM. The sensitivity (0.2917 μA/μM) and detection limit (0.195×10−7 μMDA) of this electrode are 21 times higher and 11.5 times lower than those found in our previous paper. The sensor response of 9.95 μMDA was not affected by 5.0 mM of glucose, 4.5 mM of fructose, 0.58 mM of sucrose, 0.28 mM of cystine, 0.25 mM of ascorbic acid, 79.60 μM of cysteine, and 49.70 μM of uric acid and urea. The fabricated sensor was successfully tested for determination of DA in injection medicine and human blood plasma samples.

Simultaneous determination of norepinephrine, uric acid, and ascorbic acid at a screen printed carbon electrode modified with polyacrylic acid-coated multi-wall carbon nanotubes

A screen printed carbon electrode (SPCE) modified with polyacrylic acid-coated multi-wall carbon nanotubes (PAA-MWCNTs) has been prepared by the dispersion of MWCNTs in PAA aqueous solution via sonication and the followed drop-coating for the simultaneous determination of norepinephrine (NE), uric acid (UA), and ascorbic acid (AA). The presence of PAA inhibited the adsorption of AA owing to the electrostatic repulsion, but was favorable for the affinity adsorption of NE and UA via the ion exchange and hydrogen bonding mechanisms, respectively. This led to the decrease in the oxidation potential of AA and the significantly enhanced oxidation peak currents of NE and UA at the PAA-MWCNTs/SPCE. By cyclic voltammetry and differential pulse voltammetry, the oxidation potentials of NE, UA, and AA at the PAA-MWCNTs/SPCE in a ternary mixture were found to be well resolved so that their simultaneous determination could be achieved. Furthermore, the interaction of NE, UA, and AA with PAA accounted for their electrochemical responses at different pH values. Also, the effect of pH revealed that the oxidation of NE, UA, and AA at the PAA-MWCNTs/SPCE all involved the transfer of two electrons. In addition, by differential pulse voltammetry, the linear dependence of peak current on the concentration was obtained in the ranges of 0–10, 0–30, and 100–1000 μM with the lowest detection limits of 0.131, 0.458, and 49.8 μM for NE, UA, and AA, respectively.

Simultaneous detection of dopamine and ascorbic acid using polyglycine modified carbon paste electrode: A cyclic voltammetric study

A carbon paste electrode (CPE) was modified by electropolymerisation of glycine in 0.2 M acetate buffer solution (ABS) at pH 5.0. Cyclic voltammetric technique (CV) was used to study the electrochemical properties of the polymer film. The polyglycine modified CPE was used for the electrochemical detection of dopamine (DA) and ascorbic acid (AA). The polyglycine modified CPE showed excellent electrocatalytic activity for the oxidation of DA and AA. Polymer film has negative charges in its backbone, and DA exists as the positively charged species whereas AA exists as the negatively charged one. In cyclic voltammetric measurements favorable ionic interaction (i.e. electrostatic attraction) between DA and polyglycine contributes to the oxidation potential of DA compared to that of bare electrode. The oxidation potential of AA is negatively shifted due to electrostatic repulsion of anionic AA with the polyglycine film. Polyglycine modified CPE exhibited excellent ability to separate DA from AA by means of cyclic voltammetric technique and the separation potential of their anodic peak potential was apart as wide as 0.197 V in pH 5.0 ABS containing 0.1 mM DA and 1 mM AA at the scan rate of 50 mV/s. The detection limit of the current technique was found to be 1 × 10 −7 M for DA in the presence of 1 × 10 −3 M of AA. Hence this electrode can be used for the selective determination of DA in the presence of high concentration of AA.

Electrochemical Behavior of Ascorbic Acid on Hexaaza Macrocyclic Copper(II) Complex Modified Au Electrode and Its Analytical Application

AbstractA novel hexaaza macrocyclic copper(II) complex modified Au electrode was developed and used for the measurement of ascorbic acid. Its electrochemical behavior was investigated by cyclic voltammetry and scanning electrochemical microscopy. This modified electrode exhibited electrocatalytic response to the oxidation of ascorbic acid. Compared with a bare gold electrode, the modified electrode exhibited a 250 mV shift of the oxidation potential of ascorbic acid in the cathodic direction and a marked enhancement of the current response. The response current revealed a good linear relationship with the concentration of ascorbic acid in the range of 5.0×10−7 to 4.0×10−5 mol/L and the detection limit of 4.8×10−8 mol/L (S/N=3) in the pH 4.0 Tris‐HCl buffer of ascorbic acid in fruits without any other pretreatment. The concentrations of ascorbic acid measured by this method were in good agreement with the literature values. It is very promising for the modified electrode to be used as an electrochemical sensor for the detection of ascorbic acid.

Synergistic effect of a catechin-immobilized poly(3,4-ethylenedioxythiophene)-modified electrode on electrocatalysis of NADH in the presence of ascorbic acid and uric acid

Catechin is a polyphenolic flavonoid that can be isolated from a variety of natural sources, including tea leaves, grape seeds, and the wood and bark of trees such as acacia and mahogany. In our experiments, catechin was immobilized on PEDOT/GC (poly(3,4-ethylenedioxythiophene)/glassy carbon)-modified electrodes and used as a mediator for NADH (nicotinamide adenine dinucleotide) oxidation. The effect of the PEDOT thickness on the surface coverage of the catechin molecules was studied using cyclic voltammetry. The electrochemical properties and the effect of pH on the redox properties of the immobilized catechin molecules were studied by cyclic voltammetry in phosphate solution. The electrocatalytic oxidation of NADH at different electrode surfaces such as the bare GC-, the PEDOT/GC-, the catechin/GC- and the catechin/PEDOT/GC-modified electrodes was explored in phosphate solution at pH 7. In the catechin/PEDOT/GC-modified electrode, the PEDOT film plays an important role in resolving the oxidation potentials of ascorbic acid and NADH into two peaks that occur at the same potential for the catechin/GC-modified electrode surface. The heterogeneous electron transfer rate constant for NADH oxidation at the catechin/PEDOT/GC-modified electrode was determined using the rotating disk electrode technique and found to be 9.88 × 10 3 M −1 s −1. The amperometric determination of NADH at the catechin/PEDOT/GC electrode was tested. The sensitivity of the electrode was 19 nA/μM.

Simultaneous voltammetric detection of dopamine and ascorbic acid using didodecyldimethylammonium bromide (DDAB) film-modified electrodes

A voltammetric method using a surfactant didodecyldimethylammonium bromide (DDAB) film-modified electrode was developed for simultaneous measurement of various combinations of neurotransmitters and ascorbic acid. The DDAB-modified film has the positive charge and neurotransmitters (dopamine, norepinephrine, and epinephrine) existed as the positively-charged species in the neutral solution whereas AA (ascorbic acid) as a negatively-charged one. Both the cyclic voltammetry (CV) and square-wave voltammetry were used for the measurement of neurotransmitters by means of the DDAB/GC-modified electrode in phosphate buffer solution of pH 6.5. Well-separated voltammetric peaks were observed for dopamine and ascorbic acid at the DDAB/GC-modified electrodes. The oxidation potential of ascorbic acid was shifted to a more positive potential due to a positive electro-catalytic activity of the DDAB/GC-modified electrode while neurotransmitters such as dopamine or norepinephrine or epinephrine were oxidized at a more positive potential due to electrostatic repulsion. The rotating ring disk electrode (RRDE) method was applied to study the redox reaction mechanism of dopamine and ascorbic acid. The DDAB/GC electrode resolved the voltammetric signals of the above analytes successfully.

Electrochemical determination of ascorbic acid in fruits on a vanadium oxide polypropylene carbonate modified electrode

A novel vanadium oxide polypropylene carbonate modified glassy carbon electrode was developed and used for the measurement of ascorbic acid (AA). The electrode was prepared by casting a mixture of vanadium tri(isopropoxide) oxide (VO(OC 3H 7) 3) and poly(propylene carbonate) (PPC) onto the surface of a glassy carbon electrode. The electrochemical behavior of the VO(OC 3H 7) 3–PPC film modified glassy carbon electrode was investigated by cyclic voltammetry and amperometry. This modified electrode exhibited electrocatalytic response to the oxidation of ascorbic acid. Compared with a bare glassy carbon electrode, the modified electrode exhibits a 220 mV shift of the oxidation potential of ascorbic acid in the cathodic direction and a marked enhancement of the current response. The response current revealed a good linear relationship with the concentration of ascorbic acid in the range of 4 × 10 −8 and 1 × 10 −4 mol L −1 and the detection limit of 1.5 × 10 −8 mol L −1 ( S/ N = 3) in the pH 8.06 Britton–Robinson solution. Quantitative recovery of the ascorbic acid in synthetic samples has been obtained and the interferences from different species have been studied. The method has been successfully applied to the determination of ascorbic acid in fruits. The concentrations of ascorbic acid measured by this method are in good agreement with the literature value. It is much promising for the modified films to be used as an electrochemical sensor for the detection of ascorbic acid.