The Electrooxidation of Glucose in Phosphate Buffer Solutions: Kinetics and Reaction Mechanism

Abstract

The electrochemical oxidation of glucose on Pt at pH = 7.5 within 400 2 qRHE s 800 mV was studied by cyclic voltammetry, by taking quasistationary current-potential curves, by measuring the surface coverage of organic residues, and by analyzing the primary reaction product. The results can be summarized as follows:1. Glucono lactone is the only reaction product being formed by the anodic process. Gluconic acid is generated by hydrolysis. 2. Tafel lines had to be normalized for the uncovered surface with the help of the adsorption measurements. The apparent transfer coefficient 3. The electrochemical reaction orders of glucose and H+ were determined to be zG = 0.35 k 0.04 and zH+ = -0.38 k 0.04, resp. These results are interpreted by means of a reaction mechanism. The kinetic parameters measured are confirmed by a model calculation.is aapp = 0.37 f 0.03. Pulse Radiolytic Investigation of theRadiation-Induced Cationic Primary Processes in Carbon Tetrachloride 0. BREDE, J. B S S , and R . M E H N E R T Zentralinstitut fur Isotopen-und Strahlenforschung der Akademie der Wissenschaften der DDR, PermoserstraDe 15, 705 Leipzig (Eingegangen am 17. September 1979) By nanosecond pulse radiolysis with optical detection the observable transients measured in pure carbon tetrachloride were identified as the radical cation CCG', an ion-pair neutralization complex [CCG' ... Cl-] and an anion Cl;. If aromatic scavengers Ar were added donor-acceptor complexes of the type [Cl + Ar] and aromatic radical cations Are+ were observed and kinetically characterized. -A stepwise charge transfer from CCl;' to alkanes and further to aromatics was used to derive information on the nature of an existing primary positive charge carrier which probably has the structure of an excited radical cation CC&'*. Based on these observations an overall reaction me.chanism describing the radiation-induced processes of cationic origin in the carbon tetrachloride/scavenger system was formulated. The Thermal Conductivity of Hydrogen, Deuterium and Their Mixtures Near Room Temperature within the Pressure Range 2 -36 MPaThe paper reports new, absolute measurements of the thermal conductivity of hydrogen and deuterium as well as of two binary mixtures of the two components at 27.5"C. The measurements have been carried out as a function of density in a transient hot-wire instrument and extend over the pressure ranges 2 -13 MPa for the mixtures and 2 -36 MPa for pure hydrogen. The uncertainty in the absolute thermal conductivity data is estimated as one of +0.2%. The measurements have been arranged so as to yield the ratio of the thermal conductivities of the two pure gases with essentially the same uncertainty. -The Eucken factors for the two pure hydrogen isotopes at zero density have been derived and differ from each other by as much as 1.8% which is well beyond experimental uncertainty. The existing kinetic theory expressions for the Eucken factor of a polyatomic gas are not able to account for this difference. On the other hand the first density coefficients ...

PtAu/C based bimetallic nanocomposites for non-enzymatic electrochemical glucose detection

“…In both ␣-and ␤-glucose, the hydrogen atom tethered to C 1 (dehydrogenation at C 1 carbon) carbon is activated, as the acidity of the hemi-acetalic OH group is stronger than the alcoholic OH. This is well supported by the early studies on electrochemical oxidation of glucose on Pt in neutral phosphate buffer solution [20,22]. ␤-Glucose is the most reactive species among the possible anomeric forms and the geometric orientation of the hydrogen atom bound to the anomeric carbon is thought to be responsible for the poor reactivity of ␣-glucose [21].…”

Alkaline glucose oxidation on nanostructured gold electrodes

“…3, red curve). Peak "a" (-0.7 V) was attributed by many authors to dehydrogenation of anomeric carbon under adsorption control [23][24][25]. The dehydrogenation of the anomeric carbon peak was deeply investigated by Beden et al on a platinum electrode [26,27].…”

Abiotic (Nonenzymatic) Implantable Biofuel Cells

“…At the anode, glucose is predominantly oxidized to glucono-lactone, releasing two electrons and two protons. Gluconolactone undergoes hydrolysis to form gluconic acid [14]. A number of studies showed that gluconic acid can be further oxidized, but at comparably slower reaction rates [15][16][17][18][19].…”