Complex Mixture Analysis by Photoionization Mass Spectrometry with a VUV Hydrogen Laser Source.
Abstract
Trace organic analysis in complex matrix presents one of the most challenging problems in analytical mass spectrometry. When ionization is accomplished non-selectively using electron impact, extensive sample clean-up is often necessary in order to isolate the analyte from the matrix. Sample preparation can be greatly reduced when the VUV H2 laser is used to selectively photoionize only a small fraction of compounds introduced into the ion source. This device produces parent ions only for all compounds whose ionization potentials lie below a threshold value determined by the photon energy of 7.8 eV. The only observed interference arises from electron impact ionization, when scattered laser radiation interacts with metal surfaces, producing electrons which are then accelerated by potential fields inside the source. These can be suppressed to levels acceptable for practical analysis through proper instrumental design. Results are presented which indicate the ability of this ion source to discriminate against interfering matrix components, in simple extracts from a variety of complex real world matrices, such as brewed coffee, beer, and urine. Keywords: Photoionization; Mass Spectrometry; Hydrogen Lasers; Ultraviolet lasers; Vacuum Ultraviolet Radiation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 06, 1985
- Accession Number
- ADA162401
Entities
People
- M. Bonner Denton
- Thomas C. Huth
Organizations
- University of Arizona