title: Electrochemical behavior of ascorbic acid at a 2,2'-[3,6-Dioxa-1,8-octanediylbis(nitriloethylidyne)]-bis-hydroquinone carbon paste electrode.
abstract: Electrocatalytic oxidation of ascorbic acid (AA) at a carbon paste electrode, chemically modified 2,2'-[3,6-dioxa-1,8-octanediylbis(nitriloethylidyne)]-bis-hydroquinone, was thoroughly investigated. The results of cyclic voltammetry, double potential-step chronoamperometry, linear sweep voltammetry and differential pulse voltammetry (DPV) studies were used for the prediction of the mechanism of electrochemical oxidation of AA mediated with 2,2'-[3,6-dioxa-1,8-octanediylbis(nitriloethylidyne)]-bis-hydroquinone at the surface of the modified electrode. The diffusion coefficient (D = 2.45 x 10(-5) cm(2) s(-1)) and the kinetic parameters such as the electron transfer coefficient (alpha = 0.34) were also determined. The results of DPV using the 2,2'-[3,6-dioxa-1,8-octanediylbis(nitriloethylidyne)]-bis-hydroquinone-modified electrode were applied in a highly sensitive determination of AA in drug samples. A linear range of 3.0 x 10(-6) - 1.2 x 10(-4) M and the detection limit (3sigma) 3.8 x 10(-7) M were obtained for DPV determination of AA in buffered pH 7.00 solutions (0.1 M phosphate buffer).
authors.affiliation: Department of Chemistry, Faculty of Science, Yazd University, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Taleat
authors.forename: Mohammad
authors.initials: M
authors.lastname: Mazloum Ardakani
authors.forename: Hossein
authors.initials: H
authors.lastname: Naeimi
authors.forename: Hadi
authors.initials: H
authors.lastname: Beitollahi
authors.forename: Maryam
authors.initials: M
authors.lastname: Nejati
authors.forename: Hamid
authors.initials: H
authors.lastname: Reza Zare
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002021:Buffers; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D004058:Diffusion; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D006863:Hydrogen-Ion Concentration; D006873:Hydroquinones / Q000737:chemistry*; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D002021:Buffers; D006873:Hydroquinones; D002244:Carbon; D001205:Ascorbic Acid