Table of Contents

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.

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.

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.

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.

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.

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.