Detection system for a gas chromotograph
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.
- Assignee:
- Dept. of Energy
- Patent Number(s):
- US 4432225
- OSTI ID:
- 6918167
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400100* -- Analytical & Separations Chemistry
ACCURACY
AROMATICS
BEAMS
CHEMICAL ANALYSIS
CHROMATOGRAPHY
COOLING
EMISSION SPECTRA
EMISSION SPECTROSCOPY
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUORESCENCE SPECTROSCOPY
GAS CHROMATOGRAPHY
HYDROCARBONS
LASER SPECTROSCOPY
LASERS
MOLECULAR BEAMS
ORGANIC COMPOUNDS
POLYCYCLIC AROMATIC HYDROCARBONS
POPULATION INVERSION
QUANTITATIVE CHEMICAL ANALYSIS
SENSITIVITY
SEPARATION PROCESSES
SPECTRA
SPECTROSCOPY