Organic phase enzyme electrodes

Saini, Selwayan; Hall, Geoffrey F.; Downs, Mark E. A.; Turner, Anthony P. F.

doi:10.1016/0003-2670(91)87002-o

Cited by 123 publications

(46 citation statements)

References 49 publications

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“…The finding that antibodies can retain activity and high levels of selectivity in highly non-aqueous environments has not only presented the opportunity of performing conventional immunoassays within such environments, but also the intriguing possibility of organic-phase immunosensing, a fact recognised by Saini et al [8]. Direct immunoassay approaches demand the selection of appropriate solvent tolerant antibodies.…”

Section: Organic-phase Immunosensorsmentioning

confidence: 99%

“…The potential pitfalls of organic-phase electrochemistry include deposition of charged species on electrode surfaces, significant electro-migration of redox couple species and establishment of a reliable reference potential. The latter problem can be overcome through linkage of a quasi-reference potential to a standard test couple [94] or use of an aqueous reference electrode in contact with the test solution [8], a less accurate approach owing to the creation of an unknown interfacial liquid junction potential. Such problems are usually minimal when working with hydrophilic water-miscible solvents.…”

Section: Electrochemistry In the Organic-phasementioning

confidence: 99%

“…This approach is compatible with the requirements of field-based biosensor devices, namely minimal sample preparation, assay simplicity and low cost. Further conjectured benefits include analyte pre-concentration in small volumes of extraction solvent leading to increased detection limits, improved assay stability and operational temperature range, and the possibility of 'tailoring' the antibody-antigen interaction through quaternary structure distortion in the presence of solvent to create favourable reversible binding kinetics [8]. The fact that many enzymes can also function in organic solvents, sometimes with enhanced kinetic properties, potentially allows such entities to be used as immunoassay labels [9].…”

Section: Introductionmentioning

confidence: 99%

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Organic phase immunosensors

Setford¹,

Kröger²,

Turner³

1999

Analusis

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Many analytical methods involving non-polar analytes require solvent extraction prior to measurement. The analysis procedure is greatly simplified if the method is able to function effectively in the more non-polar solvent extract. This consideration, coupled with the increasing need for simple, specific and rapid diagnostic and screening tools, has focused interest in the development of organic-phase immunosensors.

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Section: Organic-phase Immunosensorsmentioning

confidence: 99%

Section: Electrochemistry In the Organic-phasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Organic phase immunosensors

Setford¹,

Kröger²,

Turner³

1999

Analusis

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“…This is different from that of the tyrosinase/silica sol-gel electrode in aqueous solution [25]. This could result from the different hydrophobicity of the immobilization matrix and the altered substrate solubility in the organic solvent [26]. At high phenol concentrations, platform responses are observed, showing the characteristic of the Michaelis ± Menten kinetic mechanism.…”

Section: Optimization Of the Experimental Parametersmentioning

confidence: 93%

Pure Organic Phase Phenol Biosensor Based on Tyrosinase Entrapped in a Vapor Deposited Titania Sol‐Gel Membrane

Yu¹,

Ju²

2004

Electroanalysis

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A novel amperometric biosensor was constructed for the determination of phenols in pure organic phase. This biosensor was fabricated by immobilizing tyrosinase in a titania sol-gel membrane which was obtained with a vapor deposition method. This method was facile and avoided the calcination step needed in conventional titania sol-gel process. The titania sol-gel membrane could effectively retain the essential water layer around the enzyme molecule needed for maintaining its activity in organic phase. The experimental parameters such as solvent and operating potential were optimized. At À 100 mV this biosensor showed a good amperometric response to phenols in pure chloroform without any mediator and rehydration of the enzyme. For catechol determination the sensor exhibited a fast response of less than 5 seconds. The sensitivity of different phenols was as follows: catechol > phenol > p-cresol. Additionally, the apparent Michaelis-Menten constants of the encapsulated tyrosinase to catechol, phenol and pcresol were found to be 0.15 AE 0.003, 0.17 AE 0.008 and 0.21 AE 0.004 mM, respectively. The biosensor had also good reproducibility and stability. This work provided a promising platform for the construction of pure organic phase biosensors and the determination of substrates with poor water solubility.

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“…Reversed micelles or water-in-oil emulsions (composed of an organic solvent as the continuous phase, water as the dispersed phase and a surfactant acting as emulsifying agent) can be considered as universal solubilization media for both hydrophilic and hydrophobic analytes. Other features of the use of reversed micelles for developing enzyme electrodes are the easy control of the amount of water necessary in order that the biocatalytic activity of the enzymes can be retained [3] (this is an important advantage with respect to organic phase enzyme electrodes where the organic solvent is unmiscible with water), and the greatly simplified enzyme immobilization scheme onto the electrode surface.…”

Section: Introductionmentioning

confidence: 99%

Development of an amperometric enzyme biosensor for the determination of the antioxidant tert‐butylhydroxyanisole in a medium of reversed micelles

et al. 1996

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A biocdtalytic scheme, based on the enzyme tyrosinase, has been developed for the determination of the antioxidant ferfbutylhydroxyanisole (BHA) in food samples. Reversed micelles formed with ethyl acetate as organic solvent, dioctyl sulfosuccinate (AOT) as emulsifying agent, and phosphate buffer of pH 7.4 as aqueous phase, has been employed as the working medium. The potential applied to the tyrosinase electrode, as well as the temperature of the working reversed micelle, the percentage of aqueous phase, and the pH of the phosphate buffer solution have been optimized. The stability of the enzyme electrode with time has been also evaluated. A very good selectivity has been found with respect to potential interference from other substances commonly present in commercial antioxidant mixtures in food. An Eastman-AQ/enzyme immobilization approach has been employed to improve the stability of the tyrosinase biosensor in reversed micelles flowing streams. A flow injection method with amperometric detection for the determination of BHA has been developed and applied to the analysis of this antioxidant in commercial biscuits.

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Organic phase enzyme electrodes

Cited by 123 publications

References 49 publications

Organic phase immunosensors

Organic phase immunosensors

Pure Organic Phase Phenol Biosensor Based on Tyrosinase Entrapped in a Vapor Deposited Titania Sol‐Gel Membrane

Development of an amperometric enzyme biosensor for the determination of the antioxidant tert‐butylhydroxyanisole in a medium of reversed micelles

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