Bioelectrochemical Monitoring of Phenols and Aromatic Amines in Flow Injection Using Novel Plant Peroxidases

Abstract

An amperometric flow system combined with a glucose oxidase-mutarotase reactor was optimized and used to determine aromatic amines and phenols using peroxidase-modified graphite electrodes. An increase in currents upon injection of the analyzed substrate was shown to be approximated by a Michaelis-Menten type dependence. The detection limit was calculated as 3 times the noise, and the sensitivity was calculated as Imax/K(m)app. Commercially available horseradish peroxidase was compared with tobacco anionic and peanut cationic peroxidases for determination of aromatic amines and phenols. Detection limits of 10 nM for determination of o-aminophenol and o- and p-phenylenediamine achieved with a tobacco peroxidase-modified electrode give a promise for further improvements in sensitivities and detection limits of biosensors.

Tobacco Peroxidase as a New Reagent for Amperometric Biosensors

“…4a), whose value is related to the concentration of the substrate added by the Michaelis-Menten equation (Fig. 4b) [18]. A minimum detection limit (about 10 nM) was obtained in the case of o-aminophenol, o-phenylenediamine, and p-phenylenediamine (Table 2).…”

“…Determination of aminophenols with the use of tobacco peroxidase. Table 1 summarizes the kinetic characteristics of peroxidases from various sources immobilized on a rotating graphite electrode [18]. As follows from Table 1, TOP exhibited a minimum rate constant of reaction with hydrogen peroxide (k 1 ), as compared with enzymes from other sources.…”

“…On the other hand, the appearance of a good mediator dramatically increases the signal. Mediated electron transfer on the addition of a good substrate can form the basis for the quantitative determination of this compound [18].…”

“…The screening for phenols and amines [18] demonstrated that, after attaining a steady current under flow conditions in the absence of a substrate, the addition of these substrate mediators to TOP resulted in a current spike (Fig. 4a), whose value is related to the concentration of the substrate added by the Michaelis-Menten equation (Fig.…”

“…In addition to the fundamental studies of natural glycosylated TOP performed in 1996-1999 [3][4][5][6], which demonstrated a number of practically promising properties of this enzyme, the new enzyme was also tested for analytical purposes [7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”