Sensors

200 KiB

Open AccessArticle

Studies of the Cataluminescence of Benzene Homologues onNanosized γ–Al₂O₃/Eu₂O₃ and the Development of a Gas Sensorfor Benzene Homologue Vapors

by Jieshan Lu, Xiaoan Cao, Canying Pan, Lianfeng Yang, Guangbo Lai, Jianling Chen and Cuiqin Wu

Sensors 2006, 6(12), 1827-1836; https://doi.org/10.3390/s6121827 - 26 Dec 2006

Cited by 16 | Viewed by 11908

Abstract

The cataluminescence (CTL) of benzene and the benzene homologues tolueneand xylene on nanosized γ–Al₂O₃ doped with Eu₂O₃ (γ–Al₂O₃/Eu₂O₃) was studied and asensor of determining these gases was designed. The proposed sensor showed highsensitivity and selectivity at an optimal temperature of 432 ºC, a wavelength of 425 nm anda flow rate of 400 mL/min. Quantitative analysis was performed at the optimal conditions.The linear ranges of CTL intensity versus concentration of the benzene homologues were asfollows: benzene 2.4~5000 mL/m³, toluene 4.0~5000 mL/m³ and xylene 6.8~5000 mL/m³,with detection limits (3σ) of 1.8 mL/m³, 3.0 mL/m³ and 3.4 mL/m³ for each one,respectively. The response time of this system was less than 3 s. The coexistence of othergases, such as SO₂, CO and NH₃, caused interference at levels around 11.7%, 5.8% and8.9% respectively. The technique is a convenient and fast way of determining the vapors ofbenzene homologues in air. Full article

(This article belongs to the Special Issue Gas Sensors)

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1604 KiB

Open AccessArticle

The Redox Behaviour of Randomly Dispersed Single Walled Carbon Nanotubes both in the Absence and in the Presence of Adsorbed Glucose Oxidase

by Michael E. G. Lyons and Gareth P. Keeley

Sensors 2006, 6(12), 1791-1826; https://doi.org/10.3390/s6121791 - 20 Dec 2006

Cited by 41 | Viewed by 11643

Abstract

The electrochemical behaviour of SWCNTs randomly dispersed on gold and glassy carbon electrode surfaces was characterised via cyclic voltammetry and complex impedance spectroscopy, using the ferri/ferrocyanide couple as a redox active test probe . In subsequent investigations glucose oxidase (GOx) was adsorbed onto the SWCNT ensemble without apparent denaturation of the enzyme. Cyclic voltammetry and potential step chronoamperometry were used to quantify and understand the process of electron transfer between the immobilised protein redox site and the working electrode. The effect of pH on the system was also investigated. In particular, we have shown that, for the calculation of electron transfer rate constants for surface-immobilised redox systems, chronoamperometry is preferable to voltammetry, which has been the technique of choice until now. Full article

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911 KiB

Open AccessArticle

Modelling the Transport and Kinetics of Electroenzymes at the Electrode/Solution Interface

by Michael E.G. Lyons

Sensors 2006, 6(12), 1765-1790; https://doi.org/10.3390/s6121765 - 19 Dec 2006

Cited by 14 | Viewed by 8418

Abstract

The solution phase transport and direct electrode kinetics of electro-enzymes are described in terms of a simple model in which the steady state reaction/diffusion equation for enzyme is solved subject to physically realistic boundary conditions. Two physically realizable situations are described: the semi infinite and the membrane bounded case. Limiting expressions for the reaction flux are derived and the kinetic possibilities discussed geometrically in terms of kinetic case diagrams. Full article

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166 KiB

Open AccessReview

Zeolite-based Materials for Gas Sensors

by Xiaowen Xu, Jing Wang and Yingcai Long

Sensors 2006, 6(12), 1751-1764; https://doi.org/10.3390/s6121751 - 13 Dec 2006

Cited by 157 | Viewed by 16099

Abstract

This review of 53 references deals with the uses of zeolites and zeolite-basedmaterials for developing gas sensors. The potential of these materials is highlighted andavenues for further research are suggested. Full article

(This article belongs to the Special Issue Gas Sensors)

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420 KiB

Open AccessReview

Overview of Physical Models and Statistical Approaches for Weak Gaseous Plume Detection using Passive Infrared Hyperspectral Imagery

by Tom Burr and Nicolas Hengartner

Sensors 2006, 6(12), 1721-1750; https://doi.org/10.3390/s6121721 - 6 Dec 2006

Cited by 38 | Viewed by 10370

Abstract

The performance of weak gaseous plume-detection methods in hyperspectral long-wave infrared imagery depends on scene-specific conditions such at the ability to properly estimate atmospheric transmission, the accuracy of estimated chemical signatures, and background clutter. This paper reviews commonly-applied physical models in the context of weak plume identification and quantification, identifies inherent error sources as well as those introduced by making simplifying assumptions, and indicates research areas. Full article

(This article belongs to the Special Issue Gas Sensors)

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152 KiB

Open AccessArticle

Pulsed Amperometry for Anti-fouling of Boron-doped Diamond in Electroanalysis of β-Agonists: Application to Flow Injection for Pharmaceutical Analysis

by Chanpen Karuwan, Thitirat Mantim, Patcharin Chaisuwan, Prapin Wilairat, Kate Grudpan, Piyada Jittangprasert, Yasuaki Einaga, Orawon Chailapakul, Leena Suntornsuk, Oraphan Anurukvorakun and Duangjai Nacapricha

Sensors 2006, 6(12), 1837-1850; https://doi.org/10.3390/s6121837 - 26 Jan 2006

Cited by 31 | Viewed by 12937

Abstract

This work presents the construction and application of boron-doped diamond(BDD) thin film electrode as sensor for the determination of three β-agonists, viz.salbutamol, terbutaline and clenbuterol. Although well-known as a chemically inertmaterial, BDD film however shows fouling in detection of these compounds using fixedpotentialmode amperometry. A suitable waveform for pulsed amperometric detection(PAD) was developed and used to determine the agonist compounds. It was seen that thedeveloped PAD significantly refreshed the BDD surface for long-term detection in flowinjection analysis. Linear working ranges were 0.5-100 μM, 1.0-100 μM and 0.5-50 μM forsalbutamol, terbutaline and clenbuterol, respectively. The developed PAD-BDD system wasapplied to successfully determine salbutamol and terbutaline in commercial pharmaceuticalproducts. The methods were validated with a capillary electrophoresis method. Full article

(This article belongs to the Special Issue Sensors in Flow Analysis)

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Sensors, Volume 6, Issue 12 (December 2006) – 6 articles , Pages 1721-1850

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