Thin‐film antimony–antimony‐oxide enzyme electrode for penicillin determination

Flanagan, Michael T.; Carroll, Natalie

doi:10.1002/bit.260280721

Cited by 17 publications

(4 citation statements)

References 16 publications

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“…To obtain an 'accelerated lifetime' array of biosensors (i.e. an array that shows, over a conveniently short period in the laboratory, the noise, drift and sensor dropout that will characterize a biosensor array in a harsh environment) we have modified our fabrication of evaporated thin film antim ony-antim ony oxide enzyme electrodes (Flanagan & Carroll 1986) to give a somewhat less reliable sensor. We have replaced our antimony evaporation procedure with the antimony pH microelectrode fabrication procedure of Vieira & Malnic (1968).…”

Section: Antimony-antimony Oxide Penicillinase Electrodesmentioning

confidence: 99%

“…Penicillin monitoring electrodes were then made by immobilizing, on the tip of the electrode, penicillinase (from Bacillus cereus) by the gluteraldehyde cross-linking method of Mascini & Guilbault (1977). Penicillin monitoring was performed in 1 mM phosphate buffer, pH 7.0, at a temperature of 23 °C, with a calomel reference electrode as previously described (Flanagan & Carroll 1986).…”

Section: Antimony-antimony Oxide Penicillinase Electrodesmentioning

confidence: 99%

“…In this paper we will address the problem of the limited and unpredictable lifetimes. Now that biosensors can be made conveniently and cheaply as multiple arrays, such as enzyme-linked isfets (Kuriyama et al 1985) and antim ony-antim ony oxide enzyme electrodes (Flanagan & Carroll 1986), the possibility of electronically detecting and eliminating an individual faulty sensor in such an array arises. Superficially, this is an analogous problem to that of designing majority voters, e.g.…”

Section: Introductionmentioning

confidence: 99%

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Outlier detection in the design of fault-tolerant biosensor arrays

Flanagan

Taha

Carroll

1987

Phil. Trans. R. Soc. Lond. B

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The possibility of fabricating a digital voter that will detect and eliminate a faulty sensor in an array of identical biosensors is examined. Eleven statistical outlier-detection procedures are applied to the responses of an array of antimony-antimony oxide penicillinase electrodes and to an extensive computer simulation of small array responses. A Dixon excess-over-range test and a maximum normalized residual test are shown to be safe outlier-detection procedures that will detect a faulty sensor and offer an algorithm that may be economically implemented in hardware. The Iglewicz & Martinez test, which can be implemented more conveniently in software, is shown to be very efficient when applied to the real data. However, its poorer performance when applied to the simulated data suggests that further examination of this test is required.

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Section: Antimony-antimony Oxide Penicillinase Electrodesmentioning

confidence: 99%

Section: Antimony-antimony Oxide Penicillinase Electrodesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Outlier detection in the design of fault-tolerant biosensor arrays

Flanagan

Taha

Carroll

1987

Phil. Trans. R. Soc. Lond. B

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“…They observed a highly reproducible response behavior of their electrodes, even a t very low values of the concentration of the monitored substances. More recently, pH-sensitive enzymic field effect transistors (ENFET) have successfully been fabricated by Caras et al (1985b.c) and Flanagan and Carroll (1986) for monitoring glucose and benzyl-penicillin. The physicochemical phenomena involved in the functioning of these electrodes are much more complex than those of other product-specific enzyme electrodes for the following three reasons.…”

Section: Introductionmentioning

confidence: 98%

Design of enzyme‐pH electrodes

1987

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A theoretical framework useful for predicting the steady state response of enzyme-pH electrodes is developed. The model takes into account that the catalytic activity of the enzymes as well as the degree of dissociation of the product acids and bases is strongly dependent upon the local pH, and that buffering salts present in solution facilitate the transport of H+ ions. It is shown that the electrode should operate under substrate diffusion-limited conditions and the concentration of H+ ions should not have steep variations within the enzymic membrane. This condition can be fulfilled by adjusting the buffer concentration in the bulk solution. In the latter conditions the electrode response does not depend on the actual kinetics of the enzymic reaction, and can be predicted by an algebraic equation. The predictions are in excellent agreement with the experiments on penicillinase-pH and urease-pH electrodes.

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Modeling of enzyme‐potentiometric sensors involving acid‐ or base‐forming reactions

Ogundiran

Varanasi

Ruckenstein

1991

Biotech & Bioengineering

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Enzyme-potentiometric sensors in which the chemical conversion of the analyte leads to the formation of an acid and/ or a base can often display complex response characteristics. In these sensors, the electrochemically monitored species is usually the H + ion (pH-based sensors). However, in some cases the conjugate-ion of the H' (or OH-) ion of the acid (or base) produced can also be monitored-a specific example being the urease-NH4+ sensor. The response of both types of sensors is strongly affected by: (1) the degree of dissociation of the products and their transport properties in the enzymic film, (2) the amounts of pH-buffers present in the test solution, (3) the test solution's pH, and (4) the diffusion coefficients of the various species. In this article, a previously developed theoretical model for pH-based sensors-in which the differences in diffusivities of t h e various species were ignored-is generalized to accommodate for such differences, and extended to the latter of the above two types of sensors. It is shown that when the sensor operates under analyte diffusioncontrolled conditions, the response of either type of sensor can be predicted by a simple algebraic equation which is independent of the actual kinetics of the enzymic reaction.

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Thin‐film antimony–antimony‐oxide enzyme electrode for penicillin determination

Cited by 17 publications

References 16 publications

Outlier detection in the design of fault-tolerant biosensor arrays

Outlier detection in the design of fault-tolerant biosensor arrays

Design of enzyme‐pH electrodes

Modeling of enzyme‐potentiometric sensors involving acid‐ or base‐forming reactions

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