Chemical sensor design

Morf W.E., Seiler K., Lehmann B., Behringer C., Hartman K., Simon W., Carriers for chemical sensors design features of optical sensors (optodes) based on selective chromoionophores, Pure Appl. Chem. 1989 61 1613. 

Another relevant issue for sensors is packaging. In particular, for chemical sensors designed for working in solution, it is necessary to prevent the solution from any contact with the semiconductor layer (if this is not the sensitive layer of the device). Microfluidic systems [35,36] coupled with the sensor s active areas offer a valid solution to this problem because they allow the flow of the solution to the active area to be controlled and channeled, without compromising the semiconductor layer. For pressure/strain sensors the packaging should not compromise the mechanical flexibility of the whole structure. 

Some of the chapters In this volume present novel approaches to chemical sensor design which do not fit conveniently into the preceding outline. 

Lobnik A, Turel M, Urek SK (2012) Optical chemical sensors design and applications. In Wang W (ed) Advances in chemical sensors. InTech, New Yoik, pp 3-28... 

Chemical templation has been widely employed for the synthesis of mechanically interlocked strucmres. Some of these interlocked systems have potential in future chemical sensor design. Leigh and coworkers prepared many [2]rotaxanes via an active-metal template synthesis. For example, a [2]rotaxane R14 synthesized via a catalytic... 

One important application of amperometry is in the construction of chemical sensors. One of the first amperometric sensors to be developed was for dissolved O2 in blood, which was developed in 1956 by L. C. Clark. The design of the amperometric sensor is shown in Figure 11.38 and is similar to potentiometric membrane electrodes. A gas-permeable membrane is stretched across the end of the sensor and is separated from the working and counter electrodes by a thin solution of KCl. The working electrode is a Pt disk cathode, and an Ag ring anode is the... 

There are three advantages to study molecular recognition on surfaces and interfaces (monolayers, films, membranes or soHds) (175) (/) rigid receptor sites can be designed (2) the synthetic chemistry may be simplified (J) the surface can be attached to transducers which makes analysis easier and may transform the molecular recognition interface to a chemical sensor. And, which is also a typical fact, this kind of molecular recognition involves outside directed interaction sites, ie, exo-receptor function (9) (see Fig. 5b). 

The development of highly selective chemical sensors for complex matrixes of medical, environmental, and industrial interest has been the object of greate research efforts in the last years. Recently, the use of artificial materials - molecularly imprinted polymers (MIPs) - with high recognition properties has been proposed for designing biomimetic sensors, but only a few sensor applications of MIPs based on electrosynythesized conductive polymers (MIEPs) have been reported [1-3]. 

Cheung, P. W., Fleming, D. G., Ko, W. H., Neuman, M. R., eds. Theory, Design and Biomedical Applications of Solid State Chemical Sensors, West Palm Beach, Florida, CRC Press 1978... 

Let us start with a definition. Semiconductor chemical sensor is an electronic device designed to monitor the content of particles of a certain gas in surrounding medium. The operational principle of this device is based on transformation of the value of adsorption directly into electrical signal. This signal corresponds to amount of particles adsorbed from surrounding medium or deposited on the surface of operational element of the sensor due to heterogeneous diemical reaction. 

Semiconductor chemical sensors are characterized by low cost, small size, extra high sensitivity (often unattainable in other analytical techniques) as well as reliability. Moreover, concentration of particles detected is being transformed directly into electrical signal and electronic design of the device is the simplest one which can be arranged for on the active part of the substrate. 

Even listing all above problems and requirements leading to their solution indicates that development of the method of semiconductor chemical sensors opens a wide research domain. In order to resolve this problems and implement all capabilities of the method of semiconductor sensors there are two ways now the old trial and error approach and approach related to further studies of physical and chemical properties of surface phenomena, reactions and processes underlying this method. It is quite clear that the second approach is more promising in order to obtain semiconductor sensors designed for the use in accurate scientific studies and for practical gas analysis. 

The monograph is intended for the scientists and engineers specialized in physical-chemistry of heterogeneous and heterogeneous-homogeneous processes and designing of semiconductor chemical sensors. 

Many physio-chemical processes involve a time delay between the input and output. This delay may be due to the time required for a slow chemical sensor to respond, or for a fluid to travel down a pipe. A time delay is also called dead time or transport lag. In controller design, the output will not contain the most current information, and systems with dead time can be difficult to control. 

In these sensors, the intrinsic absorption of the analyte is measured directly. No indicator chemistry is involved. Thus, it is more a kind of remote spectroscopy, except that the instrument comes to the sample (rather than the sample to the instrument or cuvette). Numerous geometries have been designed for plain fiber chemical sensors, all kinds of spectroscopies (from IR to mid-IR and visible to the UV from Raman to light scatter, and from fluorescence and phosphorescence intensity to the respective decay times) have been exploited, and more sophisticated methods including evanescent wave spectroscopy and surface plasmon resonance have been applied. 

The key design elements of (non-spectroscopic) optical chemical sensors and biosensors are ... 

The goal of this book is to cover the full scope of electrochemical sensors and biosensors. It offers a survey of the principles, design and biomedical applications of the most popular types of electrochemical devices in use today. The book is aimed at all scientists and engineers who are interested in developing and using chemical sensors and biosensors. By discussing recent advances, it is hoped to bridge the common gap between research literature and standard textbooks. 

J.F. Schenck, Technical difficulties remaining to the application of ISFET devices, in Theory, Design and Biomedical Applications of Solid State Chemical Sensors (P.W. Cheung, ed.), pp. 165—173. CRC Press, Boca Raton (1978). 

This chapter provides an overview of the basic principles and designs of such sensors. A chemical sensor to detect trace explosives and a broadband fiber optic electric-field sensor are presented as practical examples. The polymers used for the trace explosive sensor are unpoled and have chromophores randomly orientated in the polymer hosts. The electric field sensor uses a poled polymer with chromophores preferentially aligned through electrical poling, and the microring resonator is directly coupled to the core of optical fiber. 

In this section, the sensitivity characteristics of HRI-coated LPGs have been investigated to outline their dependence on the overlay thickness and mode order. In addition, the experimental results here presented provide the basic design criteria for the development of highly sensitive in fiber refractometers and chemical sensors for specific SRI ranges. 

On the basis of the reported results, it is evident how the selection of the overlay thickness and of the specific cladding mode offers a certain degree of flexibility to design chemical sensors with optimized sensitivity in the desired SRI range. 

Grate, J. W. Abraham, M. H., Solubility interaction and design of chemically selective sorbent coatings for chemical sensor and arrays, Sens. Actuators B 1991, 3, 85 111... 

In recent years, rapid advancements in photonic technologies have significantly enhanced the photonic bio/chemical sensor performance, especially in the areas of (1) interaction between the light and analyte, (2) device miniaturization and multiplexing, and (3) fluidic design and integration. This has led to drastic improvements in sensor sensitivity, enhanced detection limit, advanced fluidic handling capability, lower sample consumption, faster detection time, and lower overall detection cost per measurement. 

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