Sensing carbon dioxide

Oter, O., Ertekin, K., Topkaya, D., and Alp, S., Emission-based optical carbon dioxide sensing with HPTS in green chemistry reagents Room-temperature ionic liquids, Anal. Bioanal. Chem., 386,1225-1234, 2006. 

Stange G. and Stowe S. (1999) Carbon-dioxide sensing structures in terrestrial arthropods. Microsc. Res. Tech. 47, 416 -27. 

Clayton W A 1993 Improved capacitive moisture sensors Sensors 10 16-22 Ishihara T et al 1991 Application of mixed oxide capacitor to the selective carbon dioxide sensor. I. Measurement of carbon dioxide sensing characteristics J. Electrochem. Soc. 138 173-6... 

Ishihara,T., Kometani, K., Hashida, M. and Takita, Y. (1991), AppUcation of Mixed Oxide Capacitor to the Selective Carbon Dioxide Sensor. Part 1. Measnrement of Carbon Dioxide Sensing Characteristics , Journal of the Electrochemical Society, 138,1,173-6. 

Figure 5.9. Pn 3 m cubic phase matrix containing the catalyst. Reprinted from Scheme 5.1 R Rowinski, R. Bilewicz, M.J. Stebe and E. Rogalska, A concept for immobilizing catalytic complexes on electrodes cubic phase layers for carbon dioxide sensing, Analytical Chemistry, 74(7), 1554-1559 (2002). Copyright 2002, with permission of American Chemical Society.

Ishihara T, Kometani K, Mizuhara Y, Takita Y (1991a) Mixed oxide capacitor of CuO-BaSnOj as a sensor for CO detection over a wide range of concentration. Chem Lett 20(10) 1711-1714 Ishihara T, Kometani K, Hashida M, Takita Y (1991b) Application of mixed oxide capacitor to the selective carbon dioxide sensor. I. Measurement of carbon dioxide sensing characteristics. J Electrochem Soc 138 173-176 Ishihara T, Kometani K, Mizuhara Y, Takita Y (1992) Application of a mixed oxide capacitor to the selective carbon dioxide sensor. II. COj sensing characteristics of a CuO-based oxide capacitor. J Electrochem Soc 139 2881-2885... 

As a matter of fact, the main advantage in comparison with HPLC is the reduction of solvent consumption, which is limited to the organic modifiers, and that will be nonexistent when no modifier is used. Usually, one of the drawbacks of HPLC applied at large scale is that the product must be recovered from dilute solution and the solvent recycled in order to make the process less expensive. In that sense, SFC can be advantageous because it requires fewer manipulations of the sample after the chromatographic process. This facilitates recovery of the products after the separation. Although SFC is usually superior to HPLC with respect to enantioselectivity, efficiency and time of analysis [136], its use is limited to compounds which are soluble in nonpolar solvents (carbon dioxide, CO,). This represents a major drawback, as many of the chemical and pharmaceutical products of interest are relatively polar. 

Such changes in the pH are sensed by the inner glass electrode. The overall cell potential is thus determined by the carbon dioxide concentration in the sample ... 

Promoters may influence selectivity by poisoning undesired reactions or by increasing the rates of desired intermediate reactions so as to increase the yield of the desired product. If they act in the first sense, they are sometimes referred to as inhibitors. An example of this type of action involves the addition of halogen compounds to the catalyst used for oxidizing ethylene to ethylene oxide (silver supported on alumina). The halogens prevent complete oxidation of the ethylene to carbon dioxide and water, thus permitting the use of this catalyst for industrial purposes. 

Like carbon dioxide, (dissolved) ammonia can be sensed via the pH changes it induces when diffusing into a small cavity containing an internal buffer69,70. The same is true for sulfur dioxide71. Selectivity for one of these... 

D.L. Simpson and R.K. Kobos, Potentiometric microbiological assay of gentamicin, streptomycin, and neomycin with a carbon dioxide gas-sensing electrode. Anal. Chem. 55, 1974-1977 (1983). 

The various combustion methods differ primarily in the method of measuring the carbon dioxide generated from the organic carbon. The first really sensitive carbon dioxide detector and the one still most used is the non-dispersive infrared gas analyser. The detecting element senses the difference in absorption of infrared energy between a standard cell filled with a gas with no absorption in the infrared, and a sample cell. Water vapour is the only serious interference, hence the carbon dioxide must be dried before any measurements are made. 

Lan and Mottola [14] have presented two continuous-flow-sensing strategies for the determination of C02 in gas mixtures using a special reaction cell. Both approaches are based on the effect of the complex of Co(II) with phthalocyanine as a rate modifier of the CL emission generated by luminol in the absence of an added oxidant agent, which is enhanced by the presence of C02 in the system. This enhancement allows the fast and simple determination of carbon dioxide at ppm levels (v/v) in atmospheric air and in human breath. In the first case, a continuous monitoring system was applied however, because the flow of expired gas is not constant, a discrete sample introduction approach was used in the analysis of C02 in breath. 

In the sense that diamonds react imperceptibly slowly at room temperature (either with oxygen to form carbon dioxide, or in its transformation to the more stable graphite), it is true that diamonds last forever. However, at elevated temperatures, diamond will bum to form C02 (g) and thus the statement is false. Also, the transformation... 

Carbon dioxide Gas sensing 3 x 10 2 to 10-5 Volatile organic acids... 

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