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Optimisation of the electrodeposition of Prussian Blue onto mirrored glassy carbon electrodes yielded a modified electrode practically insensitive to oxygen reduction. At the same time the electrode activity towards hydrogen peroxide reduction was extremely high. This allowed the detection of hydrogen peroxide by electroreduction over a wide potential range. Flow-injection investigations of this...
Based on self-assembled biotinylated disulfide derivative monolayer on gold electrode, the sensors immobilized monolayer or multilayer membranes composed of avidin and biotinlabeled glucose oxidase (B GOD) or of avidin-B GOD complex (ABC) and B COD were prepared. The present technique may be useful for controlling the enzyme content of the sensors in molecular level by repeating the deposition...
The development of a glucose sensor suitable for use with whole blood is described. It is based on anodic oxidation at + 700 mV of hydrogen peroxide with a platinum electrode covered with a gas permeable membrane. Glucose reacts with glucose oxidase immobilised on the external side of the membrane, and forms hydrogen peroxide which is able to cross the gas permeable membrane due to its high vapour...
Poly(ethylene glycol)-modified glucose oxidase was immobilized in a poly(vinyl alcohol) cryogel membrane, obtained by a freezing-thawing cyclic process, to obtain a suitable amperometric glucose sensor. The covalent linkage between PEG and GOD molecule improved the physical immobilization of enzyme in the polymeric matrix, by decreasing its loss in time. Sensor behaviour was evaluated electrochemically...
A novel and robust amperometric enzyme electrode for the determination of glucose was constructed by immobilizing glucose oxidase (GOD) and Os(bpy) 2 Cl-poly(4-vinyl)pyridine (Os-PVP) complex multilayers on thiol self-assembled monolayers surface. The apparent Michaelis-Menton constant K m ' increased with increasing the number of Os-PVP/GOD multilayers. The concentration range of...
A sensor for H 2 O 2 amperometric detection based on a Prussian Blue (PB) bulk modified carbon screen-printed electrode was developed. It has been optimised with respect to the lowest limit of detection achieved. PB was made chemically by the reaction of FeCl 3 with K 4 [Fe(CN) 6 ]. The resulting powder, obtained by forced crystallisation induced by acetone,...
Two different biodegradable latex polymers functionalised by hydroxy (1) or gluconamide (2) groups proved to be good immobilisation matrixes for glucose oxidase. The responses of these biosensors to glucose additions were measured by potentiostating the modified electrodes at 0.6 V/SCE in order to oxidise the hydrogen peroxide generated by the enzymatic oxidation of glucose in the presence of oxygen...
A glucose biosensor with enzyme immobilised by sol-gel technology was constructed and evaluated. The glucose biosensor reported is based on encapsulated GOX within a sol-gel glass, prepared with 3-aminopropyltriethoxy silane, 2-(3,4-epoxycyclohexyl)-ethyltrimetoxy silane and HCl. A flow system incorporating the amperometric biosensor constructed was developed for the determination of glucose in the...
In this paper an enzymatic fluorometric sensor for glucose determination in drinks is presented. The sensor film was obtained by immobilisation of glucose oxidase chemically modified with a fluorescein derivative (GOx-FS) in a polyacrylamide polymer. During the enzymatic reaction the changes in the fluorescence intensity of the GOx-FS are related to the glucose concentration. Working in FIA mode,...
A glucose biosensor using an enzyme-immobilized eggshell membrane and oxygen electrode for glucose determination has been fabricated. Glucose oxidase was covalently immobilized on an eggshell membrane with glutaraldehyde as a cross-linking agent. The glucose biosensor was fabricated by positioning the enzyme-immobilized eggshell membrane on the surface of a dissolved oxygen sensor. The detection scheme...
A screen-printed amperometric biosensor based on carbon ink double bulk-modified with MnO 2 as a mediator and glucose oxidase as a biocomponent was investigated for its ability to serve as a detector for bonded glucose in different compounds, such as cellobiose, saccharose, (-)-4-nitrophenyl-β-d-glucopyranoside, as well as in beer samples by flow-injection analysis (FIA). The biosensor could...
In this work a method is presented for the enzymatic determination of glucose using fluorescence anisotropy. During the enzymatic reaction a change in the fluorescence anisotropy of the glucose oxidase (GOx) is produced; the reaction time at which this change appears (t m ) depends on the glucose concentration. A theoretical study has been developed which enables: (a) the correlation of this...
The performance of amperometric glucose biosensors based on the dispersion of glucose oxidase (GOx) and copper oxide within a classical carbon (graphite) paste composite is reported in this work. Copper oxide promotes an excellent electrocatalytic activity towards the oxidation and reduction of hydrogen peroxide, allowing a large decrease in the oxidation and reduction overpotentials, as well as an...
This work reports a hybrid flow-injection analysis (FIA)/sequential-injection analysis (SIA) method for the rapid enzymatic assay of glucose with soluble glucose oxidase (GOD). The method relies on the sequential injection of segments of the sample and of a solution of enzyme by means of a multi-port selection valve in a flowing water stream. As the two zones are swept downstream, they overlap and...
C/Fe nanocomposite (CFN) was synthesized by a procedure similar to an exfoliation/adsorption process to intercalate Fe 3+ into graphite oxide (GO) layers and would be reduced in a H 2 atmosphere. The results of X-ray diffractometry (XRD) and transimission electron microscopy (TEM) show that the form of CFN is carbon nanotube–Fe nanoparticle composite with α-Fe distributed on the nanotube...
The preparation and characterization of an amperometric glucose biosensor based on the entrapment of glucose oxidase (GOx) in a polyacrylamide microgel is described. This study proves that polyacrylamide microgels provide an excellent matrix for GOx immobilization that can be used as a biological material in amperometric biosensors. The interference produced by ascorbic and uric acid has been eliminated...
A wide size range of SiO 2 particles were synthesized and were used as enzyme immobilization carriers to fabricate glucose biosensors. The size of the particles was in the range of 17–520nm. These biosensors could be operated under physiological conditions (0.1M phosphate buffer, pH 7.2). Particle size could affect the performance of SiO 2 modified glucose biosensors drastically. The...
We are proposing for the first time the use of a Nafion/multi-walled carbon nanotubes dispersion deposited on glassy carbon electrodes (GCE) as a new platform for developing enzymatic biosensors based on the self-assembling of a chitosan derivative and different oxidases. The electrodes are obtained by deposition of a layer of Nafion/multi-wall carbon nanotubes dispersion on glassy carbon electrodes,...
A long-life capillary enzyme bioreactor was developed that determines glucose concentrations with high sensitivity and better stability than previous systems. The bioreactor was constructed by immobilizing glucose oxidase (GOx) onto the inner surface of a 0.53mm i.d. fused-silica capillary that was part of a continuous-flow system. In the presence of oxygen, GOx converts glucose to gluconic acid and...
A new amperometric biosensor for glucose was developed based on adsorption of glucose oxidase (GOx) at the gold and platinum nanoparticles-modified carbon nanotube (CNT) electrode. CNTs were covalently immobilized on gold electrode via carbodiimide chemistry by forming amide linkages between carboxylic acid groups on the CNTs and amine residues of cysteamine self-assembled monolayer (SAM). The fabricated...
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