Enzyme electrodes, use

G.F. Hall, D.J. Best, and A.P.F. Turner, The determination of p-cresol in chloroform with an enzyme electrode used in the organic phase. Anal. Chim. Acta 213,113-119 (1988). 

Matsumoto et al (41) prepared a multi-enzyme electrode using glucose oxidase, invertase, mutarotase, fructose-5-dehydrogenase, and catalase to simultaneously detect glucose, fructose, and sucrose in fruit juices and soft drinks. Detection of multi-components by enzyme sensors was also reported in analysis of sucrose and glucose in honey (42) and drinks (43), and L-malate and L-lactate in wines (44). 

N.F. Almeida and A.K. Mulchandani, A mediated amperometric enzyme electrode using tetrathiafulvalene and L-glutamate oxidase for the determination of L-glutamic acid, Anal. Chim. Acta, 282(2) (1993) 353-361. 

M. Kyrolainen, S.M. Reddy and P.M. Vadgama, Blood compatibility and extended linearity of lactate enzyme electrode using polyCvinyl chloride) outer membranes, Anal. Chim. Acta, 353 (1997) 281-289. 

A great number of enzymes have already been combined with electrodes. In some cases, several possible enzymatic routes may be selected, depending on the substrate to be analyzed. One such example is that used to determine aspartame (Fig. 3) (18-20). Enzyme electrodes use, ideally, only one enzyme and monitor the main substrate-enzyme reaction, for example, glucose oxidase-glucose. If the main substrate-enzyme reaction is not electrochemically detectable or if signal amplification is required, bi- or trienzymatic sequences may be applied. 

The third generation of enzyme electrodes uses direct electrical communication between the redox centers of the enzymes and the electrode surface. This con-... 

Figure 8. (A) The assembly of an electrically contacted glutathione reductase monolayer. (B) The rate of bioelectrocatalyzed reduction of oxidized glutathione (GSSG) by the electrically contacted enzyme electrode using various connecting chain lengths (a) n = 2, (b) n = 5, (c) = 11. Application of -0.72 V vs. SCE to the enzyme electrode in the presence of GSSG (10 mM). The experiments were performed in 0.1 M phosphate buffer, pH 7.2, under Ar.

The measurements performed with the two types of biosensors show that the linear range of this type of enzyme electrodes using natural oxygen mediator manifest a wide range of measurement. The immobilised enzyme showed high operative stability, which makes the measurements easily reproducible. Both electrodes have very good correlation coefficients and a small standard deviation. 

Fig. 55. Schematic representation of a reagentless enzyme electrode using electrochemical regeneration of NAD for the determination of reduced dehydrogenase substrates.

Figure I4-2 Schematic view of an enzyme electrode using a double recycling system for the determination of ATP or ADP. PK = pyruvate kinase HK = herokinase LOD = lactate oxidase LDH = lactate dehydrogenase PEP = phosphoenolpyruvat Reproduced from [327] with permission from Marcel Dekket, Inc.

Scheller, F. W., Renneberg, R., Schubert, F., Coupled Enzyme Reactions in Enzyme Electrodes Using Sequence, Amplification, Competition, and Antiinterference Principles , in Methods in Enzymology Vol. 137, Colowick, S. P., Kaplan, N. O., Mosbach, K. (eds) San Diego Academic Press, 1988, pp. 29-44. 

An enzyme electrode using collagen immobilized cholesterol oxidase for the microdetermination of free cholesterol has been proposed by Coulet and his co-workers [234, 235]. A combined system with collagen bound oxidase and soluble esterase was used by Clark et al. [236]. 

While most water analysis for phosphate is laboratory based, it is predicted that the emergence of robust, sensitive, and commercially available portable and online instruments for analysis of phosphate and TP will replace a major part of this analytical load. Such a move is likely to be enhanced by the development of sensitive phosphate selective enzyme electrodes using amperometric detection, which would provide a viable and selective alternative to PMB spectrophotometry. Further advances toward miniaturized flow systems are also expected. 

Tran-Minh, C. and Pandey, PC. (1990) Insecticide determination with enzyme electrodes using different enzyme immobilization techniques. Biosens. Bioelectron., 5, 461. 

In 1990, Yao et al. proposed two different alternatives to determine MSG in seasonings using immobilized GIOD a packed-bed reactor and a lab-made flow-through enzyme electrode used as a detector [19]. Both configurations are tested in a FIA system with a simple channel manifold to compare the performance of the enzyme with... 

Another small array for pesticide determination, based on amperometric enzyme electrodes, using tyrosinase, peroxidase, acetylcholinesterase and butyrylcholinesterase, and measuring enzyme inhibition, has been reported... 

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