Applications ethanol sensor

The oxide-semiconductor-based ethanol sensor is being used to screen intoxicated drivers. In the test condition on the road, the ambient concentrations of CO and N02 can be up to 100 and lOppm due to the emissions from gasoline and diesel engines, respectively.61 The results shown in Fig. 12.6 suggest that the present sensors may be applied for selective detection of ethanol. Acetone is a very rare component in an ordinary ambient atmosphere. However, the expiration of a diabetes patient can contain acetone.62 Acetone concentration in breath air can reach up to 300 ppm in the case of an aceto-acidotic coma related to diabetes mellitus.63,64 This might interfere the ethanol sensor. A high selectivity to ethanol is required for such applications. The SZ sensor at 300°C and the ZW sensor at 400°C can satisfy these requirements. On the contrary, to examine the health condition of a diabetes patient, selective detection of acetone without the interference with alcohol is desirable. In this case, the W sensor at 400°C will be of advantageous. 

Basically, ethanol sensors designed for use in traffic control can be used for this purpose. However, their function is based on a cooperative proband [26]. Sedated or anesthetized patients are not able to carry out the necessary procedures. In addition, the electrochemical sensors used suffer interference from most anesthetic gases. For future application, IR sensors which distinguish between ethanol and anesthetic gases have to be designed on the basis of today s IR sensors. 

Ethanol is a common chemical material in the indnstry for alimental mannfactnring, cosmetic prodnction, and organic synthesis [107]. The ethanol sensors find application in various areas, such as drunken driving, monitoring of fermentation, and other processes in chemical indnstries [108,109], Ethanol is also one of the major canses of traffic accidents in the advanced conntries, so the laws and regnlations are made to improve the fitness of their people by changing the allowed alcohol level from time... 

R. Wu, Y. Huang, M. Yu, T.H. Lin, and S. Hung, Application of m-CNTs/NaClOyPPy to a fast response, room working temperature ethanol sensor. Sens. Actuat B, 134, 213-218... 

Newer applications of macroemulsion-derived powders are now being probed. Thus, excellent performance of an ethanol sensor based on macroemulsion-synthesized chromium titanate has been reported recently [203]. In the device, the microspheres were screen-printed on pre-patterned alumina substrates with gold electrodes. Sensitivity to ethanol vapor both in dry and humid air was found to be dependent on the particle size, and thus, could be tailored. 

Pal, R Nandi, D. Misra, T. N. Immobilization of alcohol dehydrogenase enzyme in a Langmuir-Blodgett film of stearic acid its application as an ethanol sensor. Thin Solid Films 1994,1, 138-143. 

If the oxygen sensitive dye is replaced by a pH sensitive dye, optical pH sensors can be produced. Thus miniaturization of these sensors is easy, and multisensing systems can be set up. Different sensor types for biotechnical application are described in the literature (e.g., ethanol and chloride sensors) [23,24]. 

The use of ISEs with ion-selective membranes based on plasticized PVC, as well as glass pH electrodes, is limited to the analysis of aqueous solutions. On the other hand, sensors based on conducting polymer membranes are usually insoluble in organic solvents, which extends the range of possible applications. Electrosynthesized polypyrrole doped with calcion works as a Ca2+ sensor that can be applied as indicator electrode in the titration of Ca2+ with NaF in mixed solvents, such as water-methanol (1 1) and water-ethanol (1 1) [52], Another example is the use of polyaniline as indicator electrode in order to follow the acid-base precipitation titration of trimeprazine base with tartaric acid in isopropanol solution (see Procedure 5). 

Segmented gas-liquid (Taylor) flow was used for particle synthesis within the liquid slugs. Tetraethylorthosilicate in ethanol was hydrolyzed by a solution of ammonia, water and ethanol (Stober synthesis) [329]. The resulting silicic acid monomer Si (OH)4 is then converted by polycondensation to colloidal monodisperse silica nanoparticles. These particles have industrial application, for example, in pigments, catalysts, sensors, health care, antireflective coatings and chromatography. 

Recently, Schuhmann et al. reported ethanol biosensors by entrapping quinohemoprotein alcohol dehydrogenase and Os-complex-modified poly(vinyl imidazole) during the electrochemically induced deposition of the poly(acrylate)-based resin [80]. The sensor exhibited its efficiency and also sufficient stability for practical applications. Author claims that the reported sensor preparation process is simple, easy to control, oxygen insensitive and can be applicable to other enzyme sensors. 

For measurement of phosphatidylcholine in serum the samples were preincubated with 0.2-0.5 U phospholipase D (EC 3.1.4.4) in the presence of Triton X-100 and calcium chloride (Mascini et al. 1986 Campa-nella et al., 1988). The liberated choline was assayed by means of the choline oxidase sensor. To assay lecithin in foodstuff the samples were extracted with ethanol and diluted with buffer. In the LCA 400 Lipid Analyzer of Toyo Jozo (Japan) the same principle is used for serum samples. However, this device appears not to be suitable for routine application and has been withdrawn from the market. 

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