Glow discharge ionization source for liquid chromatography/particle beam mass spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Chromatography

Background:

• Glow discharge mass spectrometry (GDMS) is a powerful technique for elemental analysis.
• Particle beam (PB) interfaces enhance the introduction of analytes into mass spectrometers.
• Combining liquid chromatography (LC) with PB-GDMS offers a versatile analytical approach.

Purpose of the Study:

• To evaluate the analytical performance of a liquid chromatography/particle beam-glow discharge mass spectrometry (LC/PB-GDMS) system.
• To assess its applicability for both inorganic (free metals) and organic compound analysis.
• To optimize glow discharge (GD) operating parameters for enhanced sensitivity and spectral quality.

Main Methods:

• A liquid chromatography system coupled with a particle beam interface and a glow discharge source mass spectrometer was utilized.
• Glow discharge operating current and gas pressure were optimized.
• Analytical response curves, precision (RSD), and detection limits were determined for model compounds and elements.

Main Results:

• The LC/PB-GDMS system effectively introduced analytes into the glow discharge source.
• Mass spectra for inorganic species showed characteristic isotopic patterns without significant oxide formation.
• Organic compounds produced mass spectra comparable to electron impact ionization, with low detection limits (e.g., 13 ppb for caffeine, 5.8-6.1 ppb for Fe, Ag, Cs).

Conclusions:

• The LC/PB-GDMS system is a viable and sensitive detector for liquid chromatography.
• It offers accurate analysis of both inorganic elements and organic compounds.
• The system demonstrated feasibility through the separation and identification of organic constituents in diet soda.