Optical Chemical Sensors

Biomedical Diagnostics Institute, Dublin City University, Glasnevin, Dublin 9, Ireland.
Chemical Reviews (Impact Factor: 46.57). 03/2008; 108(2):400-22. DOI: 10.1021/cr068102g
Source: PubMed


Optical chemical sensors (OCS) is defined as miniaturized devices that can deliver real time and on-line information on the presence of specific compounds or ions in a complex samples. The most widely used techniques utilized in OCS are optical absorption and luminescence. In yielding analyte information, the OCS employ optical transduction techniques. This review will concentrate on developments in OCS with major emphasis from 2000 to the present day. The recent developments in this field have been driven by factors such as the availability of low-cost, miniature optoelectronic light sources and detectors, the need for multianalyte array-based sensors, specifically in the area of biosensing, advances in microfluidics and imaging technology, and the sensor network, as well as optical materials and components.

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Available from: Brian D Maccraith, Jan 18, 2014
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    • "Both luminescent methods are widely used for sensing of many parameters such as pH and the concentration of CO 2 or O 2 [25]. In a similar way, colour changing dyes can also be used for sensing purposes [23,25,26]. PCS fibres, fibre tapers, fibre tips or other structures can be coated with a polymer or silica gel containing an organic indicator dye [27]. "
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    ABSTRACT: Optical fibre carbon dioxide (CO2) sensors are reported in this article. The principle of operation of the sensors relies on the absorption of light transmitted through the fibre by a silica gel coating containing active dyes, including methyl red, thymol blue and phenol red. Stability of the sensor has been investigated for the first time for an absorption based CO2 optical fiber sensor. Influence of the silica gel coating thickness on the sensitivity and respone time has also been studied. The impact of temperature and humidity on the sensor performance has been examined too. Response times of reported sensors are very short and reach 2–3 s, whereas the sensitivity of the sensor ranges from 3 to 10 for different coating thicknesses. Reported parameters make the sensor suitable for indoor and industrial use.
    Full-text · Article · Dec 2015 · Sensors
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    • "Some of these advantages are the availability of low-cost miniature optoelectronic light sources and detectors, the versatility of formats and materials for the development of optical sensing phases, the absence of electromagnetic interferences and the flexibility for designing multi-analyte array-based sensors or for integrating optical chemical sensors into sensor networks [8]. Currently, the most commonly techniques employed in optical chemical sensors are optical absorption and luminescence [1] [6]. In this work, we focus on luminescent chemical sensors based on the measurement of luminescence lifetime. "
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    ABSTRACT: Phase-resolved luminescence measurements provide accurate estimations under low illumination conditions and/or low signal-to-noise ratio. However, the accuracy of these measurements is limited by noise. In this article we propose a procedure, based on spectral analysis of noise, for the statistical characterization of the noise affecting the luminescent signal and the determination of the standard errors affecting the modulation-factor and the phase-shift estimates. This way, in addition to the phase-resolved luminescence measurements, we provide information about the uncertainty of these measurements. The standard errors are directly estimated from the recorded signal and the procedure only requires a FFT computation, which makes it fast and easy to be implemented. The proposed method was successfully applied to an oxygen measuring system based on phase-resolved luminescence. At each single measurement, it provides, in addition to the oxygen partial pressure, the corresponding standard error. Experiments show that the standard errors estimated from FFT using one signal are coherent with the standard deviations and the root mean square errors observed from a collection of measurements.
    Full-text · Article · Oct 2015 · Sensors and Actuators B Chemical
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    • "Optical chemical sensors play an important part in industrial , environmental and clinical monitoring thanks to their low cost, possibility for miniaturization and great flexibility [1], [2]. Among different types of optical chemical sensors, colorimetric sensors are especially attractive because they recognize analytes through color change that allows obtaining the visually observed and easily measurable analytical signal [3], [4]. "
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    ABSTRACT: The paper describes an application of a kind of optical analytical method, digital color analysis (DCA), using colorimetric polymethacrylate sensors (optodes) in order to determine Cr (VI). The optodes are made of optically transparent polymethacrylate matrix (PMM) with 1.5-diphenylcarbazide immobilized. The developed optode can be used in determination of the anlytes using solid-phase spectrophotometry and calculating color coordinates as functions of absorbance spectra. Also color coordinates can be represented as basic color (e.g. RGB) data after the op-tode image digitizing. Then one can determine the content of an analyte in a sample by an appropriate color difference calculated on these coordinates. Experimental results of Cr (VI) determination show that the DCA characteristics of accuracy and precision are comparable with those of the solid phase spectrophotometry.
    Full-text · Conference Paper · Aug 2015
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