Trace Gas Analysis

Atmospheric studies (trace gases, analysis of fires and smoke, automotive emission analysis, etc.)... 

Davis, D. D., G. Smith, and G. Klauber. Trace gas analysis of power plant plumes via aircraft measurement O3, NO, and SO] Chemistry. Science 186 733-736, 1974. 

IR is one of three forms of vibrational spectroscopy that is in conunon use for process analytical measurements the other two being near-lR (NIR) and Raman. Each one of these techniques has its pros and cons and the ultimate selection is based on a number of factors ranging from sample type, information required, cost and ease of implementation. The sample matrix is often a key deciding factor. NIR has been the method of choice for many years within the pharmaceutical industry, and sample handling has been the issue, especially where solid products are involved. IR is not particularly easy to implement for the continuous monitoring of solid substrates. However, often there is no one correct answer, but often when the full application is taken into account the selection becomes more obvious. In some cases very obvious, such as the selection of IR for trace gas analysis - neither NIR nor Raman is appropriate for such applications. 

Griffith, D. W. T., and G. Schuster, Atmospheric Trace Gas Analysis Using Matrix Isolation-Fourier Transform Infrared Spectroscopy, J. Atmos. Chem., 5, 59-81 (1987). 

Smith D, Spanel P (2005) Selected ion flow tube mass spectrometry (SIFT-MS) for on-line trace gas analysis. Mass Spectrom Rev 24(5) 661-700... 

One particularly well-performing technique is PTR-MS [193-195]. On-line trace-gas analysis by proton transfer [197] has become a powerful approach, mainly owing to the higher sensitivity and lower ionisation-induced fragmen-... 

Hence, most of the relevant proton-transfer reactions involving H3O+ are slightly exoergic, and H3O+ will perform proton-transfer reactions with nearly any kind of VOC in the headspace of food products. However, H3O+ does not react with the natural components of air such as O2, N2, CO2, CO or others (see Table 15.4). The exoergicity of the proton-transfer reaction with most VOCs, however, is low enough that breakup seldom occurs. On the basis of this ionisation principle, a PTR-MS setup was developed applicable to trace-gas analysis, and aimed at speed, sensitivity, versatility and simple handling. 

Lindinger, W., Hirber, J., Paretzke, H. (1993) An ion/molecule-reaction mass spectrometer used for online trace gas analysis. Int. J. Mass Spectrom. Ion Processes 129 79-88. 

Smith, D., Spanel, P. Selected ion flow tube mass spectrometry, SIFT-MS, for on-line trace gas analysis. In Amann, A., Smith, D. (eds.) Breath Analysis for Clinical Diagnosis and Therapeutic Monitoring, pp. 3-34. World Scientific Publishing, Toh Tuck Link, Singapore (2005)... 

On the other hand, it is shown in Fig. 9.3 that much higher concentrations than 500 ng of the analyte acetone in air will not be ionized effectively. In such a case not enough further reactant ions of the analyte, which are needed for effective ionization of the molecule, are available. Here, it should be noted that IMS is suitable for trace gas analysis. 

Hansel, A., Jordan, A., Holzinger, R. Proton transfer reaction mass spectrometry on-line trace gas analysis at the ppb level. Int. J. Mass Spectrom. Ion Proc. 149, 609-619, 1995. 

Arnold, F., R. Fabian, G. Henschen, and W. Joos (1980). Stratospheric trace gas analysis from ions, H20 and HNOj. Planet. Space Sci. 28, 681-685. 

Elsenheimer DW, Valley JW (1992) In situ oxygen isotope analysis of feldspar and quartz by Nd YAG laser microprobe. Chem Geol Isotope Geosci Section 101 21-42 Elsenheimer DW, Valley JW (1993) Submillimeter scale zonation of in quartz and feldspar, Isle of Skye, Scotland. Geochim Cosmochim Acta 57 3669-3676 Esler MB, Griffith DWT, Wilson SR, Steele LP (2000) Precision trace gas analysis by FT-IR spectroscopy. 

Robert A. Beaudet is chair of the NRC Committee on Review and Evaluation of Alternative Technologies for Demilitarization of Assembled Chemical Weapons (I and II). He received his Ph.D. in physical chemistry from Harvard University and has served on U.S. Department of Defense committees that address offensive and defensive chemical warfare. Dr. Beaudet was a member of the Army Science Board and chaired a committee that addressed chemical detection and trace gas analysis. He was chair of a series of Air Force technical workshops to develop master R D plans for... 

Standing wave in the resonator are discussed. The last chapter gives a detailed discussion of the various applications of resonant photoacoustic qwctroscopy known today. These applications are concentration measurements and trace gas analysis, accurate determination of thermophysical properties, and the det tion of dynamic processes such as mixing of gases, or chemical reactions. Recent investigations of relaxation processes, spectroscopic experiments, and results obtained for aerosols are also reviewed. 

Trace-gas analysis must be performed to guarantee the efficacy of the scavenging system. The National Institutes of Occupational Safety and Health (NIOSH) recommends that trace levels of nitrous oxide must be maintained at or below 25 ppm time-weighted average and that halogenated anesthetic agents remain below 2 ppm. 

Solid samples can be a bulk material such as a polymer or a raw material, they can be a surface coating such as varnish buildup on a piston or a particle on a semiconductor wafer. Liquids can be pure or as a solution or mixture. Gases can be pure or a mixture, such as in stack gases they may also be very dilute, down to mg 1 (parts per million) level for trace gas analysis such as for atmospheric monitoring or breathing gas for divers. In addition to these possibilities, it may be necessary to carry out the analysis at temperature and pressure conditions well removed from ambient. A final complication is that pure samples are rarely encountered much more common are mixtures, often with the material of interest present as the minor component. 

In trace gas analysis, it is required to monitor compounds, frequently organics, in atmosphere at low concentrations (parts per million (mol) or lower). Mass spectrometry offers versatile instrumentation for this, particularly when sensitivity and selectivity are enhanced by special inlet techniques or ionization processes. 

SpanSl, P, Smith, D. (1996) Selected Ion Flow Tube A Technique for Quantitative Trace Gas Analysis of Air and Breath. Med. Biol. Eng. Comput. 34 409-419. 

Schelter M, Zosel J, OelBner W, Guth U, Mertig M (2012) A solid electrolyte sensor Tot trace gas analysis. Sens Actuators B. doi 10.1016/j.snb.2012.10.111... 

---