Selective detection of molecular ions and free radicals by FTS

1992 ◽  
Author(s):  
Guy Guelachvili ◽  
Pierre Martin ◽  
A. Benidar
Keyword(s):  
Free Radicals ◽  
Molecular Ions ◽  
Selective Detection

scholarly journals New Methodologies for Qualitative and Semi-Quantitative Determination of Carbon-Centered Free Radicals in Cigarette Smoke Using Liquid ChromatographyTandem Mass Spectrometry and Gas Chromatography-Mass Selective Detection

2010 ◽  
Vol 24 (2) ◽  
pp. 58-71 ◽  
Author(s):  
AR Gerardi ◽  
WM Coleman
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Free Radicals ◽  
Cigarette Smoke ◽  
Selective Detection ◽  
Selected Ion Monitoring ◽  
Relative Quantitation ◽  
Liquid Chromatography Tandem Mass ◽  
New Methodologies

AbstractSeveral approaches were explored to develop a high throughput procedure for relative determination of 14 different carbon-centered free radicals, both acyl and alkylaminocarbonyl type, in cigarette smoke. Two trapping procedures using 3-cyano-2,2,5,5-tetramethyl-1-pyrrolidinyloxy, or 3-cyanoproxyl radical (3-CNP) were designed for this study: a) trapping in solution and b) trapping on a solid support which was a Cambridge filter pad. Fresh whole smoke and vapor phase smoke from mainstream cigarette smoke from Kentucky Reference Cigarettes 2R4F, as partitioned via an unadulterated Cambridge filter pad, were transferred into each trapping system in separate experiments. The 3-CNP coated Cambridge filter pad approach was shown to be superior to the impinger procedure as described in this study. Gas chromatography coupled with mass selective detection (GC-MS) was employed for the first time as an alternate means of detecting several relatively highly concentrated radical adducts. Liquid chromatography tandem mass spectrometry (LC-MS/MS) with precursor ion monitoring and selected ion monitoring (SIM) was used for detecting the large array of radicals, including several not previously reported: formyl, crotonyl, acrolein, aminocarbonyl, and anilinocarbonyl radicals. Relative quantitation was achieved using as external calibration standards of 4-(1-pyrrolidino)benzaldehyde and nicotine. It was determined that the yield of carbon-centered free radicals by reference cigarette 2R4F was approximately 265 nmoles/cigarette at 35 mL puff/60 sec interval/2 sec duration smoking conditions.

scholarly journals Laboratory Microwave Spectroscopy of Interstellar Molecules

1987 ◽  
Vol 115 ◽  
pp. 92-92
Author(s):  
Shuji Saito
Keyword(s):  
Free Radicals ◽  
High Sensitivity ◽  
Molecular Ions ◽  
Low Noise ◽  
Frequency Region ◽  
Low Loss ◽  
High Frequency Region ◽  
Transient Molecules ◽  
Microwave Source ◽  
High Power Microwave

One of the main difficulties to identify molecular species in space has been raised by the lack of reliable spectroscopic data for various molecules, especially for chemically active free radicals and molecular ions. Some of the free radicals and molecular ions have been fundamental to the study of chemistry in space but they are too active under terrestrial conditions and are hardly produced in concentrations enough for laboratory observations. We have developed a millimeter-wave spectrometer of high sensitivity suitable for observations of transient molecules. It covers the frequency region of 30 to 410 GHz and has the sensitivity enabling us to detect molecules in a concentration of 107 molecules/cm3 (about 30 ppb). This high sensitivity is achieved by a combination of low noise and high power microwave source, low noise detector, and low loss cell in the high frequency region, assisted by a mini-computer. We have studied various diatomic and polyatomic transient species, some of which may have likely astronomical significance. They are H2D+, PO, PO2, HPO, CCO, HCCN, SiN, FeO, and CH3O.

Spectroscopy and structures of free radicals and molecular ions

1987 ◽  
Vol 7 (4) ◽  
pp. 353-388 ◽  
Author(s):  
Eizi Hirota ◽  
Shuji Saito
Keyword(s):  
Free Radicals ◽  
Molecular Ions
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