Amperometric enzyme electrodes

Albery, W. John; Bartlett, Philip N.; Bycroft, Mark; Craston, Derek H.; Driscoll, Bryan J.

doi:10.1016/0022-0728(87)87010-9

Cited by 67 publications

(7 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, the mediator can be kept in the interfacial region by attachment to a polymer chain (8) or incorporation into the immobilized enzyme (9). Another approach is based on the observation that electrode surfaces formed from conducting organic salts, such as tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ), permit electron transfer with a variety of redox enzymes without added mediator (10)(11)(12)(13)(14). The mechanism of electron transfer is not understood (15,16) but may involve homogeneous mediation by dissolved electrode components (16,17), heterogeneous redox catalysis involving a mobile surface species, or direct electron transfer (18).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Enzyme-modified organic conducting salt microelectrode

Jl¹,

De²,

Rm³

1991

Anal. Chem.

View full text Add to dashboard Cite

A miniaturized enzyme-modified electrode has been constructed and evaluated. The tip of a capillary-encased, carbon-fiber electrode is recessed, and tetrathiafulvalene-tetracyanoquinodimethane crystals are electrochemically deposited in the recessed tip. Flavoenzymes are placed in the recess by cross-linking with glutaraldehyde. The specific enzymes used are glucose oxidase to form a microbiosensor for glucose, and a combination of acetylcholine esterase and choline oxidase to form a microbiosensor for acetylcholine. The sensor is operated in an amperometric mode with Eapp = 150 mV versus a sodium saturated calomel electrode, and the response appears to be limited by the kinetics of the enzyme reaction. The effective maximum current density for the glucose electrode is greater than 600 microA/cm2. At low concentrations of glucose, oxygen provides a significant interference by attenuating the signal. The device is simple to prepare and has a rapid response time. Interference from ascorbate has been significantly reduced by the design and by addition of a layer of ascorbate oxidase. Although not yet suitable for use in tissue, the biosensors are suitable for detection in situations where oxygen concentrations do not frequently change.

show abstract

Section: Introductionmentioning

confidence: 99%

“…surements to detect submillimolar concentrations. Recently, Rice and Nicholson (12) showed that a dopamine concentration of 34 nM can be detected with cyclic voltammetry used in a repetitive mode by the use of ensemble averaging and digital smoothing techniques.…”

Section: Introductionmentioning

confidence: 99%

Enzyme-modified organic conducting salt microelectrode

Jl¹,

De²,

Rm³

1991

Anal. Chem.

View full text Add to dashboard Cite

show abstract

“…lized D-MOD on electrodes depends on the pH and the buffer composition [28,33]. When changing the pH to 8.0 and using TRIS buffer, a somewhat higher response to D-phenylalanine was obtained (see Figure 7), showing some Fl recordings of triplet injections of 0.1 mM hydrogen peroxide as well as of 1, 2, 4, 6: 8, and 10 mM D-phenylalanine.…”

mentioning

confidence: 93%

“…A series of articles has appeared on amperometric biosensors for amino acids based on a variety of detection principles, e.g., for L-amino acids with hydrogen peroxide detection [26][27][28], with oxygen detection [29][30][31], with ferrocene derivatives [321 as artificial electron acceptor facilitating the electron transfer between the enzyme and the electrode at a less positive .UOD and a less negative potential than the electrochemical reactions for hydrogen peroxide and molecular oxygen, respectively, at tetrathiafulvalene-tetracyanoquinodimethane (TTF TCNQ) conducting salt electrodes [33], direct electron transfer between enzyme and electrode [34], and as mentioned earlier on coimmobilizing HRP with L-MOD [20,21] and for D-amino acids with hydrogen peroxide detection [28], TTF TCNQ electrodes [33], and using an electrode with coimmobilized D-AAOD with HRP and using dimethylferrocene or "TF as a mediator between electrode and HRP [21]. Here we report on reagentless sensors for L-and D-amino acids based on L-or D-MOD coimmobilized with HRP in CPs.…”

Section: Introductionmentioning

confidence: 99%

Amperometric biosensors for detection of L‐ and D‐amino acids based on coimmobilized peroxidase and L‐ and D‐amino acid oxidases in carbon paste electrodes

et al. 1994

View full text Add to dashboard Cite

An apparent direct electron transfer between various electrode materials and peroxidases immobilized on the surface of the electrode has been reported in the last few years. An electrocatalytic reduction of hvdrogen peroxide promoted by the immobilized peroxidase starts at about +600 mV (vs. Ag/AgCl) at neutral pH. The efficiency of the electrocatalytic current increases as the applied potential is made more negative and starts to level off at about -100 mV (vs. Ag/AgCl). Amperometric biosensors for hvdrogen peroxide can be constructed with these kinds of peroxidase modified electrodes. By coimmobilizing a hydrogen peroxide-producing oxidase with the peroxidase, amperometric biosensors can be made responding to the substrate of the oxidase within a potential range essentially free of interfering electrochemical reactions. Sensors for L-and D-amino acids are shown based on coimmobilizing HRP with L-amino acid oxidase (L-MOD) or D-amino acid oxidase (D-MOD). The effects of the immobilization procedure, buffer (flow carrier), pH, taken amounts of enzymes, flow rate, and injection volume on the response were investigated. The addition of polvethylenimine (PEI) into the paste was found to increase the response considerably. All 20 of the most common L-amino acids could be detected.

show abstract

“…For the detection of Ch, these electrodes follow the scheme outlined in (1) and (2); in the case of ACh, the substrate is first converted to Ch according to (3). The processes occumng at the ENZYME-MODIFIED MICROELECI'RODES Electrode Preparation.…”

Section: Introductionmentioning

confidence: 99%

Enzyme-Modified Tetrathiafulvalene Tetracyanoquinodimethane Microelectrodes: Direct Amperometric Detection of Acetylcholine and Choline

Hale

Wightman

1988

Molecular Crystals and Liquid Crystals Incorporating Nonlinear

View full text Add to dashboard Cite

Microelectrodes constructed with the one-dimensional organic conducting salt lTF-TCNQ as the electrode material and modified with two enzymes, acetylcholinesterase and choline oxidase, are used to selectively detect the neurochemically important molecule acetylcholine and its metabolite choline. Kinetic analysis of the variation of w e n t with substrate concentration indicates that the rate-limiting step in these electrodes is the enzyme kinetics. Values for the electrochemical rate constant are reported and the conditions of enzyme saturation are defied.

show abstract

Amperometric enzyme electrodes

Cited by 67 publications

References 5 publications

Enzyme-modified organic conducting salt microelectrode

Enzyme-modified organic conducting salt microelectrode

Amperometric biosensors for detection of L‐ and D‐amino acids based on coimmobilized peroxidase and L‐ and D‐amino acid oxidases in carbon paste electrodes

Enzyme-Modified Tetrathiafulvalene Tetracyanoquinodimethane Microelectrodes: Direct Amperometric Detection of Acetylcholine and Choline

Contact Info

Product

Resources

About