Analysis of gas mixtures

In this technique, the stationary phase is a porous solid (such as graphite or silica gel) and the mobile phase is a gas. This type of gas chromatography demonstrates very high performance in the analysis of gas mixtures or components that have a very low boiling point. 

Another typical example of the use of the katherometer in the analysis of gas mixtures is afforded by the separation of the components of the Scott gas mixture 237. This is a standard mixture which consists of a mixture of oxygen, carbon monoxide, methane, and carbon dioxide in an excess of nitrogen. The sample is a typical mixture of gases that are liable to be found in automobile exhaust fumes and is used to test emission analyzing equipment and gas analyses apparatus. An example of such a separation carried out on a proprietary packing at 25°C is shown in figure 5. 

Although mass spectrometry has been used for the analysis of gas mixtures for many years, it is, perhaps advisable to review the nomenclature and procedures involved. The reader is referred to Table I for the definition of several commonly used phrases which are unique to this technique (5, 6, 8, 9, 18-20, 27, 29, 31). 

Hierold C and Muller R 1989 Quantitative analysis of gas mixtures with non-... 

A significant step forward was achieved by Viengerov in 1938 He used blackbody infrared sources, (such as Nemst glowers) for radiation input and a microphone to detect the acoustic signal. His goal was the analysis of gas mixtures with a photoacoustic device. The sensitivity of the analysis was limited by the background noise which is produced by absorption of radiation in the cell... 

PTR-MS and SIFT-MS have a clear advantage over most other techniques for direct analysis of gas mixtures as no derivatization, adsorption onto traps followed by desorption steps, or other sample pretreatment steps are required before the sample is admitted to the analytical instrument. A comparison between the two techruques relevant to breath-sampling has been presented recently [220]. Both technologies allow irmnediate quantification of an analyte in a gas rruxture in real time whether it be a breath sample or an envirormrental sample. As discussed in Sect. 8.4 (PTR-MS) and 8.5 (SIFT-MS), there are three main differences between these two techruques ... 

P. Weibring, J.N. Smith, H. Edner, S. Svanberg Differential absorption lidar system based on a frequency agile optical parEunetric oscillator for multi-component chemical analysis of gas mixtures. Proc. Int. Leiser Radai Conference, Vichy, Prance, July 10—14 (2000)... 

The principles of field effect devices with special regard to chemical sensing will be briefly described in the next section. It will be demonstrated how such devices can be used in sensor arrays eventually together with other types of gas sensors to make electronic noses for the identification, classification and analysis of gas mixtures (or odours) [5-7]. A truly microanalytical system, an "olfactory camera" based on a field effect transistor array is also suggested. 

If gas selectivity cannot be achieved by improving the sensor setup itself, it is possible to use several nonselective sensors and predict the concentration by model based, such as multilinear regression (MLR), principle component analysis (PCA), principle component regression (PCR), partial least squares (PLS), and multivariate adaptive regression splines (MARS), or data-based algorithms, such as cluster analysis (CA) and artificial neural networks (ANN) (for details see Reference 10) (Figure 22.5). For common applications of pattern recognition and multi component analysis of gas mixtures, arrays of sensors are usually chosen... 

Analysis of gas mixtures containing hydrogen sulfide, carbon dioxide, carbon disulfide, and air. Heinrich Deinus and Heinz Liebert (VEB Filmfabrik-Agfa Wolfen, Ger.). Faser orsch. Tex- —... 

A Perkin - Elmer model 8500 gas chromatograph provided with a GP-lOO printer was used for analysis of gas mixtures. A carbosieve S-II column (3 mX2.4 mm, Supelco) was used to analyze H2, CO and CO2, employing He as carrier gas. The absolute yield of hydrogen was determined by calibration of the GC using known volumes of hydrogen. 

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