An Organic Phase Enzyme Electrode for Cholesterol

Hall, Geoffrey F.; Turner, Anthony

doi:10.1080/00032719108052978

Cited by 66 publications

(13 citation statements)

References 10 publications

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“…One area that offers new and unique biosensing opportunities is organic-phase enzymology [ 1, 21, The ability of enzymes to catalyze reactions in organic media could lead to the detection of new (water-insoluble) substrates, improved thermal stability, operation in new environments, changes in the substrate specificity, elimination of microbial contamination, and simpler immobilization schemes. Such possibilities have already been documented in connection with the amperometric or thermal biosensing of phenolic compounds [3,4], cholesterol [ 5 ] , or peroxide species [6-81 in chloroform, toluene, acetonitrile, or dioxane. These early organic-phase enzyme electrodes have usually relied on the direct adsorption of the corresponding enzyme onto their surfaces or nearby support materials (thus, exploiting the insolubility of the enzyme in the organic media).…”

Section: Introductionmentioning

confidence: 99%

Organic‐phase biosensors based on the entrapment of enzymes within poly(ester‐sulfonic acid) coatings

1993

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The utility and advantages of the poly(ester-sulfonic acid) ionomer (Eastman AQ-55D, Eastman Chemical Products) for entrapping enzymes onto electrodes for organic-phase biosensing are described. This type of immobilization scheme relies on the stability of Eastman AQ films in various organic solvents. The resulting organic-phase enzyme elecrodes couple the entrapment of high enzyme loadings with discrimination against anionic interferences, short response times, and a rapid stabilization of the baseline current. The immobilization of the enzymes tyrosinase and horseradish peroxidase (HW) is evaluated in connection with the biosensing of phenolic and peroxide compounds in acetonitrile solutions. Various conditions of this simple preparation route are explored.

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Section: Introductionmentioning

confidence: 99%

Organic‐phase biosensors based on the entrapment of enzymes within poly(ester‐sulfonic acid) coatings

1993

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“…Recently, organic phase enzyme electrodes for cholesterol have provoked much interest, because COD was found to be stable even in solvents, such as hepme, or mixtures of chloroform: h e m e (1: 1 = v:v) [35,36].…”

Section: Discussionmentioning

confidence: 99%

Cholesterol biosensors prepared by electropolymerization of pyrrole

1993

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Biosensors for cholesterol were prepared by electropolymerization of pyrrole in solutions of 0.1 M phosphate buffer containing 10 mM NaClO, and 15 to 55 IU/mL of cholesterol oxidase at a potential of 800 mV versus a calomel reference electrode (3 M KCl). The sensors were tested for their response toward cholesterol in batch. flow-through, and flow-injection systems by detection of the hydrogen peroxide formed in the enzymatic reaction. Flow-injection analysis (FIA) measurements with an injection loop of 50 pL were performed with a high reproducibility in the range of 0 to 250 pM cholesterol with solutions of constant detergent concentration (1% Triton X-100 in 0.1 M phosphate buffer of pH 7.0) and at a flow rate of 0.2 mL/min. At this flow rate, the detection limit was approximately 5 p M cholesterol and the sample throughput was 25 injections per hour. The response of the sensors toward ascorbic and uric acid was investigated.

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“…Wang et al successfully used tyrosinase electrode to determine the phenol content of olive oil in a flow system [31]. The measurement of cholesterol in butter and margarine samples was also demonstrated with cholesterol oxidase biosensor [32]. On-line assays of secondary alcohols in untreated gasoline samples and reliable monitoring of phenol and peroxide antiseptics in pharmaceutical products were also elegantly reported [33].…”

Section: Organic Phase Enzyme Electrodes (Opees)mentioning

confidence: 99%