A New Amperometric Carbon Paste Enzyme Electrode for Ethanol Determination

Abstract

In this study, a new amperometric carbon paste enzyme electrode for determination of ethanol was developed. The carbon paste was prepared by mixing alcohol dehydrogenase, its coenzyme nicotinamide adenine dinucleotide (oxidized form, NAD þ ), poly(vinylferrocene) (PVF) that was used as a mediator, graphite powder and paraffin oil, then the paste was placed into cavity of a glass electrode body. Determination of ethanol was performed by oxidation of nicotinamide adenine dinucleotide (reduced form, NADH) generated enzymatically at þ0.7 V. The effects of enzyme, coenzyme and PVF amounts; pH; buffer concentration and temperature were investigated. The linear working range of the enzyme electrode was 4.0 Â 10 24 -4.5 Â 10 23 M, determination limit was 3.9 Â 10 24 M and response time was 50 s. The optimum pH, buffer concentration, temperature, and amounts of enzyme, NAD þ and PVF for enzyme electrode were found to be 8.5, 0.10 M, 378C, 2.0, 6.0, and 12.0 mg, respectively. The storage stability of enzyme electrode

Amperometric carbon paste enzyme electrodes for uric acid determination with different mediators

“…A number of uric acid biosensors based on carbon paste matrix have been reported 2,21,22 . The use of redox mediators in carbon paste electrodes is a promising approach to modified electrodes 27,28 .…”

Achieving Enzyme Stability Using a Simple Fabrication Procedure: The Alcohol Dehydrogenase Example

“…These properties make paper the perfect physic base for introducing microfluidic channels and to be used in Point-of-care devices [5,[8][9][10]. One disadvantage of The use of disposable and miniaturized biosensors that can detect subtract, like glucose and ethanol, in biological fluid or in food, with accuracy has been developed since the nineties [1][2][3][4][5].…”

“…The NAD-dependence and his free-diffusion is also a limitation to its use. Some strategies pass through a stable immobilization of the cofactor and enzyme in sol-gel matrices [11], immobilization of the enzymes and cofactor in nano-structured carbon platforms or carbon nanotubes modified electrodes [12][13][14], in alginate-silicate hybrid gel [15] and other polymers [3,4,16].…”

Amperometric biosensing of ethanol based on integration of alcohol dehydrogenase with a Pt/PPy--PVS/MB electrode

“…1 ADH biosensors have some important properties for ethanol monitoring, such as not being oxygen dependent and being more selective to ethanol. 1,3 However, ADH-based biosensors have some drawbacks, including the fact that they are unstable 1 and the direct electrochemical oxidation of NADH on a bare electrode needs a considerable overpotential and often occurs only at potentials higher than 0.4 V vs. a Ag/AgCl reference electrode depending on the surface properties of the electrode. 16 Great attention has been focused on decreasing the overpotential by using a mediator as a suitable electrocatalyst that can facilitate the electron transfer between the cofactor of redox enzymes and electrodes.…”