Determination of l-Ascorbic Acid by a Flow Injection Analysis with Copper(II)-Mediated Electrochemical Detection

Sano, Akira; Kuwayama, Tomoko; Furukawa, Mayuuko; Takitani, Shoji; Nakamura, Hiroshi

doi:10.2116/analsci.11.405

Cited by 11 publications

(5 citation statements)

References 21 publications

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“…In the presence of ascorbic acid the highest anodic peak current was observed at pH 5.0. The maximum value of current at this pH was in agreement with those reported earlier, for the determination of ascorbic acid by reduction of copper(II) ions [45,46]. The small decrease of the anodic current for pH<5.0 is due to the influence of H + in the equilibrium of reaction of the ascorbic acid with Cu(II) (Scheme 1).…”

Section: Effect Of Phsupporting

confidence: 91%

Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations

et al. 2003

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A carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin (CuP-Poly) is proposed for voltammetric determination of L-ascorbic acid in pharmaceutical formulations. The modified electrode allows the detection of L-ascorbic acid at lower anodic potentials than observed at unmodified electrodes. Several parameters that can influence the voltammetric response of the proposed electrode such as carbon paste composition, pH, scan rate, and possible interference were investigated. The peak current was proportional to the concentration of ascorbic acid in the range 2.0 x 10(-5) to 3.2 x 10(-3) mol L(-1) with a detection limit of 1.0 x 10(-5) mol L(-1). The stability and repeatability of the electrode for the determination of L-ascorbic acid are also discussed. Amperometric response was also recorded for electrocatalytic oxidation of the L-ascorbic acid. Concentrations of the vitamin C in pharmaceutical formulations (tablets) measured using the modified electrode and a titrimetric method are in agreement at the 95% confidence level and within an acceptable range of error.

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Section: Effect Of Phsupporting

confidence: 91%

Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations

et al. 2003

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“…Spectrophotometry (22)(23)(24)(25)(26)(27)(28)(29)(30)(31), differential pulse polarography (32), and adsorption potentiometry (33) have been used to determine both AA and DHA (upon reduction to AA) in fruit juices and other industrial products. However, these methods lack the adequate selectivity to analyze vascular and nonvascular plant extracts (22,23).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Determination ofl-Ascorbic Acid, Glutathione, and Their Oxidized Forms in Ozone-Exposed Vascular Plants by Capillary Zone Electrophoresis

Herrero‐Martínez¹,

Simó‐Alfonso²,

Ramis‐Ramos³

et al. 2000

Environ. Sci. Technol.

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Simultaneous determination of ascorbic acid (AA), glutathione (GSH), and oxidized glutathione (GSSG) in vascular plants has been achieved by capillary zone electrophoresis. A background electrolyte containing a phosphate buffer of pH 7 and hexadimethrin bromide for dynamic control of electroosmotic flow was used. Separation was performed in less than 5 min. The signal was simultaneously monitored at 265 and 200 nm. Dehydroascorbic acid (DHA) was determined in another aliquot of the same plant extract upon reduction with dl-homocysteine. Limits of detection of AA, GSH, and GSSG ranged from 0.2 to 0.8 μg mL-1, which corresponded from 0.04 to 0.16 mg per 100 g fresh weight of tomato, watermelon, and potato leaves. Plants exposed to a high ozone concentration (1600 μg m-3) in a laboratory fumigation system during 1, 2, 3, and 5 h showed progressive ozone-induced oxidative stress. This could be seen as a simultaneous decrease of the AA/(AA+DHA) and GSH/(GSH+GSSG) ratios; however, the decline rate was higher for AA/(AA+DHA) than for GSH/(GSH+GSSG) in plants cultivated in the field, in open-top chambers, during ca. 50 days with much lower ozone concentrations (mean concentrations, 10 and 80 μg m-3).

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“…Electroanalytical techniques can be used to overcome many of the problems associated with difficult analysis in complex matrices. Since AA is an electroactive compound; it is determined by using electrochemical methods such as potentiometry (Amini et al 2001;Sano et al 1995), amperometry (Fei et al 2004;Pournaghi et al 2002;Zhang et al 2000), and voltammetry (Gao et al 1993;Zare et al 2005;Dursun and Nisli 2004).…”

Section: Introductionmentioning

confidence: 99%

Flow Injection Photoamperometric Investigation of Ascorbic Acid Using Methylene Blue Immobilized on Titanium Phosphate

Dilgin

Nisli

2006

Analytical Letters

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Methylene blue (MB) was incorporated into titanium phosphate (TiP) after pretreatment of TiP with the gas, n-butyl amine. The dye is strongly retained and not easily leached from the layered host matrix. The adsorbed MB on TiP was used to prepare modified carbon paste electrodes (MCPE), which were studied voltammetrically and in amperometric flow injection (FI) mode for the electrocatalytic oxidation of ascorbic acid (AA). The electrochemical behavior of the immobilized dye was investigated with cyclic voltammetry, at a pH 7.0 phosphate buffer containing 0.5 M KCl, at different potential scan rates. The MB immobilized on the support underwent a quasireversible electrochemical redox reaction. A homemade flow-through electrochemical cell with a suitable transparent window for irradiation of the electrode surface was constructed and used for amperometric FI studies. The photoamperometric-FI conditions were optimized for sensitivity and reproducibility at a flow rate of 1.5 mL/min, a transmission tubing length of 25 cm, a sample injection volume of 100 mL, and a constant applied potential of þ100 mV vs. SCE. The calibration curve for AA was linear over the concentration range from 1.0 Â 10 26 to 2.5 Â 10 25 mol l 21 for both amperometric and photoamperometric studies. But the slope of the photoelectrocatalytic FIA 451procedure was improved about 52% compared with those obtained without irradiation. The results obtained for AA determination in some pharmaceutical products are in good agreement with those obtained using the procedure involving the reaction between triiodide and AA.

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Determination of l-Ascorbic Acid by a Flow Injection Analysis with Copper(II)-Mediated Electrochemical Detection

Cited by 11 publications

References 21 publications

Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations

Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations

Simultaneous Determination ofl-Ascorbic Acid, Glutathione, and Their Oxidized Forms in Ozone-Exposed Vascular Plants by Capillary Zone Electrophoresis

Flow Injection Photoamperometric Investigation of Ascorbic Acid Using Methylene Blue Immobilized on Titanium Phosphate

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