Detection system for a gas chromatograph

Patent · Sat Dec 31 23:00:00 EST 1983

OSTI ID:864888

Hayes, John M ^[1]; Small, Gerald J ^[1]

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1. Ames, IA

A method and apparatus are described for the quantitative analysis of vaporizable compounds, and in particular of polycyclic aromatic hydrocarbons which may be induced to fluoresce. The sample to be analyzed is injected into a gas chromatography column and is eluted through a narrow orifice into a vacuum chamber. The free expansion of the eluted sample into the vacuum chamber creates a supersonic molecular beam in which the sample molecules are cooled to the extent that the excited vibrational and rotational levels are substantially depopulated. The cooled molecules, when induced to fluoresce by laser excitation, give greatly simplified spectra suitable for analytical purposes. The laser induced fluorimetry provides great selectivity, and the gas chromatograph provides quantitative transfer of the sample to the molecular beam.

• Research Organization: Ames Laboratory (AMES), Ames, IA; Iowa State University, Ames, IA (US)
• DOE Contract Number: W-7405-ENG-82
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4432225
• OSTI ID: 864888
• Country of Publication: United States
• Language: English

Related Subjects

/73/250/
analysis
analytical
analyzed
apparatus
aromatic
aromatic hydrocarbon
aromatic hydrocarbons
beam
chamber
chamber creates
chromatograph
chromatography
chromatography column
column
compounds
cooled
creates
depopulated
described
detection
eluted
excitation
excited
expansion
extent
fluoresce
fluorimetry
free
free expansion
gas
gas chromatograph
gas chromatography
greatly
hydrocarbons
induced
injected
laser
laser excitation
laser induced
levels
method
molecular
molecular beam
molecules
narrow
orifice
particular
polycyclic
polycyclic aromatic
provides
purposes
quantitative
quantitative analysis
rotational
sample
selectivity
simplified
spectra
substantially
suitable
supersonic
transfer
vacuum
vacuum chamber
vaporizable
vibrational