Chemical Sensors

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Chemical sensors is a term which is often used in conjunction with words like molecular sensor and chemosensor, all of which more or less mean the same thing and can relate to both a designed molecule used for sensing and the analytical device that helps deliver real time information about specific compounds in which the designed molecule is used in. IUPAC defines a 'chemical sensor as a device that transforms chemical information, ranging from the concentration of a specific sample component to total composition analysis, into an analytically useful signal'. In basic terms a chemical sensor is a device which responds to a specific analyte, sometimes called a target by changing its physical or chemical properties. The analyte can be of any size starting from protons up to large cells. The basic definition of chemical sensor also includes biosensors which uses specific and sensitive biochemical and biological reactions for species recognition. Chemical sensors contain two main components; the recognition element, which is the part of the sensor that imparts selectivity so the sensor can select a specific analyte and avoid any interferences, and the transducer. Transducers are the detector part of the sensor, it responds to the change in chemical or physical property of the sensor and translates the magnitude of the signal into a readable measure of the amount of the analyte.3 There are a variety of transducers available and are sometime divided up into four major categories; electrochemical transducers, optical transducers, piezo-electric devices and thermal sensors. Chemical sensors are advancing quickly, in no small part due to the need to monitor many aspects of human health and the environment especially in recent year... ... middle of paper ... ...inds mainly to the target analyte, for example ion selective electrodes respond to particular ions although they can be interfered with by similar ions, the interference is easily measured using data given out with the electrodes. Another important factor in performance is sensitivity, it is crucial to know when analysing what concentration ranges can be measured, what the linear range is and also the detection limits. The concentration range needs to coincide with possible ranges of the target analyte. Of course like all measuring techniques the sensor needs to be precise, accurate and repeatable so that the measurements are reliable and fit for purpose. One more major factor is time, response and recovery times of the sensor are issues that are looking at to be improved with the hope of having devices with immediate response times and a very low recovery time.

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