The characterization of atmospheric pressure ionization/tandem mass spectrometry for direct atmospheric analysis
Atmospheric pressure ionization (API) has been shown to be very useful when combined with tandem mass spectrometry in performing direct atmospheric monitoring of trace compounds. The design and development of a new API source that has been developed to be compatible with a commercial, turbomolecularly-pumped triple stage quadrupole (TSQ) tandem mass spectrometer (MS/MS) is presented. This API/MS/MS instrument has been used to study (1) direct atmospheric sampling by mass spectrometry, (2) the production of ions in the atmosphere, (3) the effects of supersonic expansion on the clustering of these ions with neutral species, (4) the effectiveness of declustering of these ions by collisional means, and (5) the ability to qualitatively identify atmospheric gases. This API source utilizes a corona discharge for the primary ionization of the atmospheric molecules and an orifice system to selectively leak the ions into the mass analysis region. In developing this source, a program to model the ion optics (SIMION) has been used to aid in the design of the post-orifice lens configuration. The design of this source is such that memory effects have been essentially eliminated and the clustering of ions with molecules in the post-orifice region has been significantly reduced. Samples that have been studied include a variety of laboratory solvents. Recommendations are made for overcoming the limitations of the present API source design and lens system. These include the consideration of supersonic jet expansion theory to redesign the post-orifice lens system and additional modifications to the discharge needle system.
- Research Organization:
- Florida Univ., Gainesville, FL (USA)
- OSTI ID:
- 7198376
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AIR POLLUTION MONITORING
MASS SPECTROSCOPY
PERFORMANCE TESTING
ATMOSPHERIC PRESSURE
DESIGN
GASES
IONIZATION
ORIFICES
QUALITATIVE CHEMICAL ANALYSIS
RECOMMENDATIONS
S CODES
SAMPLING
CHEMICAL ANALYSIS
COMPUTER CODES
FLUIDS
OPENINGS
SPECTROSCOPY
TESTING
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)