Chemical microsensors and

Wohltjen, H., Jarvis, N.L., and Lint, J.R., 1991. Surface acoustic-wave (SAW) chemical microsensors and sensor arrays for industrial-process control and pollution prevention, Abstr. Papers Am. Chem. Soc. (ENVR.) 201, pp. 63-66. 

Dickert, F. L. Greibl, W. Sikorski, R. Tortschanoff, M. Weber, K. Proc. SPIE-Int. Society Opt. English (1998), 3539(Chemical Microsensors and Applications), 114-122. 

Josse R J., Zhou R., Altindal A., Dabak S., and Bekaroglu O, Sensitive properties of soluble dodecylsulfanyl phthalocyanines for organic vapors using impedance spectroscopy and QCR, Chemical Microsensors and Applications, Proceedings of SPIE-The International Society for Optical Engineering, 3539, 74-84, Boston, MA, USA, 4-5 November 1998. 

Weber J, Albers WM, Tuppurainen J, Link M, Gabl R, Wersing W, Schreiter M (2006) Shear mode FBARs as highly sensitive liquid biosensors. Sens Actuators A 128 84-88 Wohltjen H (1984) Chemical microsensors and microinstrumentation. Anal Chem 56 87A-103A... 

A chemical microsensor can be defined as an extremely small device that detects components in gases or Hquids (52—55). Ideally, such a sensor generates a response which either varies with the nature or concentration of the material or is reversible for repeated cycles of exposure. Of the many types of microsensors that have been described (56), three are the most prominent the chemiresistor, the bulk-wave piezoelectric quartz crystal sensor, and the surface acoustic wave (saw) device (57). 

Electrochemical Microsensors. The most successful chemical microsensor in use as of the mid-1990s is the oxygen sensor found in the exhaust system of almost all modem automobiles (see Exhaust control, automotive). It is an electrochemical sensor that uses a soHd electrolyte, often doped Zr02, as an oxygen ion conductor. The sensor exemplifies many of the properties considered desirable for all chemical microsensors. It works in a process-control situation and has very fast (- 100 ms) response time for feedback control. It is relatively inexpensive because it is designed specifically for one task and is mass-produced. It is relatively immune to other chemical species found in exhaust that could act as interferants. It performs in a very hostile environment and is reHable over a long period of time (36). 

The experimental set-up for cellular oxygen measurements (p02) consists of following components p02 measuring micro chamber (volume 0.6 microliter), polarographic microelectrode, water-bath for constant temperature, chemical microsensor connected to a strip-chart recorder and gas calibration unit. 

W. Wroblewski, A. Dybko, E. Malinowska, and Z. Brzozka, Towards advanced chemical microsensors — an overview. Talanta 63, 33—39 (2004). 

U. Guth, W. Oelbner, and W. Vonau, Investigation of corrosion phenomena on chemical microsensors. Electrochim. Acta 47, 201-210 (2001). 

R. Hintsche, C. Kruse, A. Uhlig, M. Paeschke, T. Lisec, U. Schnakenberg, and B. Wagner, Chemical microsensor systems for medical applications in catheters. Sens. Actuators B. B27, 471 —473 (1995). 

Reliable packaging of chemical microsensors is a challenging task owing to the different requirements for the transducer part (freely accessible with medium or sample contact) and associated electronics (completely protected and shielded), so that only a few prototype packages have been presented so far [23,140]. 

B. Panchapakesan, D.L. DeVoe, M.R. Widmaier, R. Cavicchi, and S. Semancik. Nanoparticle engineering and control of tin oxide microstructures for chemical microsensor applications , Nanotechnology 12 (2001), 336-349. 

A. Hierlemann and H. Baltes. CMOS-based chemical microsensors Analyst 128 (2003), 15-28. 

Background. The term microsensor denotes a transducer that, in some fashion, exploits advanced miniaturization technology, whether an adaptation of integrated circuit technology, or some other microfabrication technique. Within the past decade, a myriad of microsensors have been developed, with capabilities for measurement of temperature, pressure, flow, position, force, acceleration, chemical reactions, and the concentrations of chemical species. The latter measurements, of chemical species, are intrinsically more difficult than the measurement of mechanical variables because in addition to requirements of accuracy, stability, and sensitivity, there is a requirement for specificity. 

The efforts and advances during the last 15 years in zeolite membrane and coating research have made it possible to synthesize many zeolitic and related-type materials on a wide variety of supports of different composition, geometry, and structure and also to predict their transport properties. Additionally, the widely exploited adsorption and catalytic properties of zeolites have undoubtedly opened up their scope of application beyond traditional separation and pervaporation processes. As a matter-of-fact, zeolite membranes have already been used in the field of membrane reactors (chemical specialties and commodities) and microchemical systems (microreactors, microseparators, and microsensors). 

Lewis N. S., Electronic nose chip microsensors for chemical agent and explosives detection, California Institute of Technology Noyes Laboratory, Pasadena, and California... 

Koickal, T. I, Hamilton, A., Tan, S. L., Covington, I, Gardner, J. W. and Pearce, T. (2005) Smart interface circuit to ameliorate loss of measurement range in chemical microsensor arrays. Proceedings of the IEEE Instrumentation and Measurement Technology Conference. Ottawa, Ont., Canada. 

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