Proton Monitoring reactions

Fig. 15.14 Analytical techniques for time-resolved headspace analysis. An electronic nose can be used as a low-cost process-monitoring device, where chemical information is not mandatory. Electron impact ionisation mass spectrometry (EI-MS) adds sensitivity, speed and some chemical information. Yet, owing to the hard ionisation mode, most chemical information is lost. Proton-transfer-reaction MS (PTR-MS) is a sensitive one-dimensional method, which provides characteristic headspace profiles (detailed fingerprints) and chemical information. Finally, resonance-enhanced multiphoton ionisation (REMPI) TOFMS combines selective ionisation and mass separation and hence represents a two-dimensional method. (Adapted from [190])...

Lindinger, W., Hansel, A., Jordan, A. (1998) Proton-transfer-reaction mass spectrometry (PTR-MS) on-line monitoring of volatile organic compounds at pptv levels. Chem. Soc. Rev. 27 347-354. 

When performing irradiations with neutrons or high-energy protons, it is common to measure the beam intensity using a monitor reaction. A thin foil of a... 

However, the desire to reduce or even eliminate the required sample preparation has led to the development of newer techniques, such as proton-transfer-reaction mass spectrometry (PTR-MS) and selected ion flow tube mass spectrometry coupled with ion mobility spectrometry (MS-SIFT IMS). These techniques allow real-time measurements within a single second. This enables analysis of gas composition during technological processes, monitoring of indoor air, and investigation of VOCs emitted by living organisms. 

Blake, R.S., Whyte, C., Monks, P.S., Ellis, A.M. Proton transfer reaction time-of-flight mass spectrometry a good prospect for diagnostic breath analysis. In Amann, A., Smith, D. (eds.) Breath analysis for clinical diagnosis and therapeutic monitoring, p. 45. World Scientific, Toh Tuck Link, Singapore (2005)... 

Examples of monitor reactions that are applied for determination of cross sections with protons are (p, pn)"C and " Al(p, 3pn) Na. Cross sections for these reactions in the energy range between 50 MeV and 30 GeV are listed in Table 8.3. and A1 monitors are used in the form of plastic or A1 foils, respectively. 

Table 8.3. Cross sections of the monitor reactions >2c(p,pn)"C and Al(p, 3pn)2 Na for various proton energies.

Gas-liquid chromatography (GLC) was used routinely to monitor reactions, in a Carlo Erba HRGC 5160 chromatograph, with a FID detector and a silicone DB-1 (bonded methyl silicone, J W Scientific, Inc., Rancho Cordova, California column, 15 m x 0,25 mm x 0,10 pm. Helium N50 was used as carrier (2 ml/min, 60 KPa, split ratio 100 1) and analyses were performed at 260°C (iiy.) oven, 170°C (7 min) 200°C (2 min, 4 C/min) 285°C (15°C/min 20 min). Melting points were determined on a Reichert Thermovar hot bench and are uncorrected. Infra-red spectra were recorded on a Perkin-Elmer 298, as liquid films in CHCI3 solution. Proton and... 

We have briefly mentioned the use of data on IMR in plasma modeling and for the understanding of interstellar molecular synthesis as well as of ionospheric chemistry, and we also want to point out the applications of IMR in various methods of chemical ionization. The most recent one, developed in our laboratory, namely proton-transfer reaction mass spectrometry (PTR-MS), allows for on-line monitoring of volatile organic compounds at levels as low as a few parts per trillion and is therefore applicable for environmental, food, and medical research involving investigations of fast metabolic and enzymatic processes. 

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