Sensitive atmospheric pressure detection of nitroaromatic compounds and NO x (x= 1,2) molecules in an ionization chamber using resonance-enhanced multi-photon ionization

Autor:	A. Clark, Ravi P. Singhal, Kenneth W. D. Ledingham, A. Marshall, C. Kosmidis, W. X. Peng, R. M. Deas
Rok vydání:	1994
Předmět:	Chemical ionization Atmospheric pressure Chemistry Analytical chemistry Laser Biochemistry Analytical Chemistry law.invention Ion Atmospheric-pressure laser ionization Volume (thermodynamics) law Ionization Ionization chamber Electrochemistry Environmental Chemistry Spectroscopy
Zdroj:	The Analyst. 119:1719
ISSN:	1364-5528 0003-2654
DOI:	10.1039/an9941901719
Popis:	Nitrobenzene and o-nitrotoluene were detected in trace concentrations in gas mixtures at atmospheric pressure in a simple unity-gain ionization chamber. The detection procedure relies on tunable ultraviolet laser radiation that identifies the characteristic wavelength dependence of the NO+ ion fragment. Sensitivity levels are 0.25 ± 0.05 ppm for nitrobenzene and 0.75 ± 0.1 ppm for o-nitrotoluene, with the current limitations being background ionization, laser power and small sampling volume. Additionally, nominally 1 ppm NO and NO2 gas samples were analysed and the saturation fluence (via a resonant two-photon process at 226.3 nm) for NO+ production from NO gas was determined. Sensitivity levels of 120 and 50 ppb were estimated from the data on NO2 and NO, respectively. It is shown that an increase in sensitivity of an order of magnitude is possible in all instances if the experimental parameters are optimized.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::011191ee71fd321dd3af8b42887b57e6 https://doi.org/10.1039/an9941901719 Zobrazit plný text záznamu