DOUBLE ELECTROPOLYMER MODIFIED PLATINUM-ELECTRODE TO FOLLOW THE KINETIC PROCESS H2O2 PLUS ASCORBIC-ACID - INFLUENCE OF THE REACTION ON AMPEROMETRIC BIOSENSOR APPLICATIONS
I. Losito et Cg. Zambonin, DOUBLE ELECTROPOLYMER MODIFIED PLATINUM-ELECTRODE TO FOLLOW THE KINETIC PROCESS H2O2 PLUS ASCORBIC-ACID - INFLUENCE OF THE REACTION ON AMPEROMETRIC BIOSENSOR APPLICATIONS, Journal of electroanalytical chemistry [1992], 410(2), 1996, pp. 181-187
A Pt electrode modified by a polypyrrole/poly(orthophenylenediamine) b
ilayer membrane able to entrap large molecules such as glucose oxidase
was used to investigate (at 27 degrees C and pH 7) the kinetics of as
corbic acid (AA) oxidation by hydrogen peroxide (H2O2 + AA --> 2H(2)O
+ DAA) by following the H2O2 concentration as a function of time. The
largely unmatched rejection characteristics of this device towards AA
permitted it to operate even in the presence of high AA/H2O2 ratios, e
.g. 1000:1. Under these conditions, pseudo-first-order kinetic constan
t values ranging from 3.26 x 10(-3) to 4.10 x 10(-3) s(-1) were obtain
ed at [AA] = 2 mM and initial [H2O2] = 2 mu M. The potential influence
of the above reaction on sensitivity and reliability of H2O2-detectin
g biosensors in the presence of AA is discussed critically, taking int
o account also the recent, and sometimes conflicting, literature views
on the problem.