Organic phase enzyme electrode

B. Wang and S.J. Dong, Organic-phase enzyme electrode for phenolic determination based on a functionalized sol-gel composite. J. Electroanal. Chem. 487, 45-50 (2000). 

L. Campanella, G. Favero, M.P. Sammartino and M. Tomassetti, Analysis of several real matrices using new mono-, bi-enzymatic, or inhibition organic phase enzyme electrodes, Anal. Chim. Acta, 393(1-3) (1999) 109-120. 

Campanella, L. Favero, G. Sammartino, M. P. Tomassetti, M., Further development of catalase, tyrosinase and glucose oxidase based organic phase enzyme electrode response as a function of organic solvent properties, Talanta 1998, 46, 595-606... 

Dong S, Guo Y. Organic phase enzyme electrodes operated in water-free solvents. Anal Chem 1994 66 3895-3899. 

Guo YZ, Dong SJ (1997) Organic phase enzyme electrodes based on organohydrogel. Anal Chem 69 1904-1908... 

Lopez M, Lopez-Cabarcos E, Lopez-Ruiz B (2006) Organic phase enzyme electrodes. Biomol Eng 23 135-147... 

Organic phase enzyme electrodes (OPEEs) have attracted considerable interest for their applications in environmental and clinical monitoring. The use of organic solvents facilitates, indeed, the detection of compounds poorly soluble in water, prevents microbial contamination, and may circumvent side reactions leading to enzyme deactivation or electrode fouling. Among the various enzymes successfully applied to the fabrication of OPEEs, polyphenol oxidase (PPO) was widely used because Kazandjian and Klibanov demonstrated, 30 years ago, the possibility for this enzyme to work in chloroform. Thanks to its excellent activity in both aqueous and organic solvents, this enzyme which catalyzes the oxidation of phenols and o-diphenols to o-quinone constitutes a convenient enzyme model for the concept and the development of new procedures of OPEE construction. 

Campanella L, De Luca S, Sammartino MP, Tomassetti M (1999) A new organic phase enzyme electrode for the analysis of organophosphonis pesticides and carbamates. Anal Chim Acta 385 59-71... 

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). 

Cross-linking an Os-polymer containing 20 PVP (Fig. 11.5) and GOx on a platinum or glassy carbon electrode (GCE) surface with glutaraldehyde, produces biosensors that are very sensitive and stable in organic phases. The CV of the enzyme electrode shows that complexing the polymer with GOx does not change... 

The field of organic chemistry has seen the most extensive use of polymeric materials as aids in effecting chemical transformation and product isolations. Polymers have been used in other, related areas of chemistry. Applications have been made in analytical chemistry (pH indicators and electrode modifiers), pharmaceutical and agricultural chemistry (controlled-release drugs, pesticides, herbicides, and fertilizers), and biochemistry (enzyme immobilization and affinity chromatography). Applications of polymers to solid-phase enzymo- and radioim-mune assays (Landon, 1977 Chard, 1978) will not be discussed since they are mainly analytical in scope. 

Mediators can be polymerized on the electrode surface prior to enzyme immobilization, co-immobilized with enzyme, or simply added to the fuel solution. Common mediators used in BFC applications include low molecular weight, polymerizable, organic dyes such as methylene green, phenazines, and azure dyes, along with other redox-active compounds such as ferrocene, ferrocene derivalives, and conductive salts [14]. These mediators are often required for nicotinamide adenine dinucleotide (NAD )- and flavin adenine dinucleotide (FAD)-dependent enzymes, such as ADH, ALDH, and GOx. MET has been achieved at both cathodic and anodic interfaces through solution-phase mediators and mediators immobilized in various ways with or near the enzymes themselves [16,17]. However, these mediated systems do have drawbacks in that the species used to assist electron transfer are often not biocompatible, have short lifetimes themselves, or cause large potential losses. Table 5.1 lists common enzyme cofactors that can mediate or undergo DET with an enzyme on the electrode. 

---