Chemically modified electrode for

One such reaction that has been studied is the electrocatalytic reduction of oxygen directly to water.25,27 The electrocatalysts for this process are often based on metal porphyrins and phthalo-cyanins. Thus a graphite electrode whose surface was modified by the irreversible adsorption of a cofacial dicobalt porphyrin dimer was able to reduce oxygen under conditions where the reduction did not occur on the bare electrode itself. Similarly, a catalytic chemically modified electrode for the oxidation of chloride to chlorine has been prepared28 where the active catalyst was reported to be a ruthenium dimer, [(bipy)2(OH)RulvORuvO(bipy)2]4+, which was reduced to the corresponding [Rum-RuIV] dimer during the reaction. 

We begin by pointing out that this concept of covering an electrode surface with a chemically selective layer predates chemically modified electrodes. For example, an electrode of this type, the Clark electrode for determination of 02, has been available commercially for about 30 years. The chemically selective layer in this sensor is simply a Teflon-type membrane. Such membranes will only transport small, nonpolar molecules. Since 02 is such a molecule, it is transported to an internal electrolyte solution where it is electrochemically reduced. The resulting current is proportional to the concentration of 02 in the contacting solution phase. Other small nonpolar molecules present in the solution phase (e.g., N2) are not electroactive. Hence, this device is quite selective. 

L. Gorton, Chemically modified electrodes for the electrocatalytic oxidation of nicotinamide coenzymes, J. Chem. Soc., Faraday Trans, 82 (1986) 1245-1258. 

Labuda J., Vanickova M., Uhlemann E., and Mickler W. (1994) Applicability of chemically modified electrodes for determination of copper species in natural waters. Anal. Chim. Acta 284, 517-523. 

The adsorption of polymers, poly(vinyl pyridine) or poly(acrylonitrile) either to coordinate metal atoms or to adsorb biopolymers has been used to prepare chemically modified electrodes for immobihzation of enzymes either by physical or by chemical adsorption (carrier binding), cross-linking, and entrapping at lattice sites or in microcapsules [43]. A wide application of these types of electrodes has been made for electrochemical reactions of biological interest [44]. 

Fig. 39. Flow injection analysis (FIA) system for the determination of glucose involving a GDH reactor and a chemically modified electrode for NADH measurement. (Redrawn from Appelqvist et al 1985).

K. M. Korfhage, K. Ravichandran, and R. P. Baldwin, Phthalocyanine Containing Chemically Modified Electrodes for Electrochemical Detection in Liquid Chromatography/Flow Injection Systems. Anal. Chem., 56 (1984) 1514. 

Murray, R. W., Modified Electrodes. Chemically Modified Electrodes for Electrocatalysis , PhiL Itans. R. Soc. Lond. A302 (1981) 2S3-26S. 

CHEMICALLY MODIFIED ELECTRODES FOR THE ELECTROCATA-LYTIC OXIDATION OF NADH... 

Korfhage, K.M., K. Ravichandran, and R.R Baldwin (1984). Phthalocyanine-containing chemically modified electrodes for electrochemical detection in liquid chromatography/flow injection systems. Ana/. Chem. 56(8), 1517. 

Wang, J., T. Golden, and R. Li (1988). Cobalt phthalocyanine/cellulose acetate chemically modified electrodes for electrochemical detection in flowing streams Multifunctional operation based upon the coupling of electrocatalysts and permselectivity. AnoZ. Chem. 60(15), 1642-1645. 

This paper reports the development of a novel chemically modified electrode for cathodic determination of hydrogen peroxide. The electrode was constructed by modifying the surface of a glassy carbon electrode with an electrochemically deposited ferrocene-modified polyaniline film from a solution of N-... 

MULCHANDANI BARROWS Chemically Modified Electrode for H2O2... 

Tab. 2 Chemically modified electrodes for electrocatalytic NAD(P)H oxidation based on inorganic and organic mediators... 

O Shea, T.J. Lunte, S.M. Chemically Modified Electrodes for Capillary Elec-trophoiesis/Electrochemistry. Anal. Chem. 1994 66, 307-311. 

Mazur, B. and Haroon, Y. (1995) Redox mode electrochemical detection approach with chemically modified electrodes for the measurement of frenolicin B (antibiotic) and related compounds in poultry feed. /. Agric. Food Chem., 43, 3042-3045. 

Wang, E., H. Ji, and W. Hou. 1991. The use of chemically modified electrodes for liquid chromatography and flow-injection analysis. Electroanalysis 3 1-11. 

E. Wang and A. Liu. Polyaniline chemically modified electrode for detection of anions in flow injection analysis and ion chromatography. Anal. Chim. Acta 252 57, (1991). 

Mehrdad E (2003) Electrocatal5dic oxidation and flow amperometric detection of hydrazine on a dinuclear mthenium phthalocyanine-modified electrode. Can J Chem 81 161-168 Korfhage BCM, Ravichandran K, Baldwin RP (1984) Phthalocyanine contain chemically modified electrode for electrochemical detection in liquid chromatography/flow injection system. Anal Chem 56 1514-1517... 

Srivastava AK, Gaichore RR (2010) Macrocyclic compounds based chemically modified electrodes for voltammetric determination of L-tryptophan using electrocatalytic oxidation. Anal Lett 43 1933-1950... 

Agraz R, Sevilla MX, Hernandez L (1993) Chemically modified electrode for the simultaneous determination of trace metals and speciation analysis. Anal Chim Acta 273 205-212... 

Another application of polymeric calixarene is shown in paper [12], in which the polymer calixarene ester 14 (Fig. 14) is used as the a chemically-modified electrode for voltameric analysis of Pb(II), Cu and Hg(II) ions in dilute aqueous solutions. 

---