Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

Legacy Department



Marcus, R. Kenneth

Committee Member

Chumanov, George

Committee Member

Anker, Jeffrey N

Committee Member

Dominy, Brian N


Since the liquid sampling-atmospheric pressure glow discharge (LS-APGD) was first developed as an excitation source for atomic emission spectroscopy, it has been improved upon and demonstrated as an ionization source for elemental mass spectrometry, molecular mass spectrometry, and ambient desorption mass spectrometry. Multiple functions coming from one package allowed the LS-APGD to hold a unique position among all atmospheric pressure glow discharges. It also has the capabilities to work with different sample forms including liquids, bulk solids, and solution residues. The high salt/matrix tolerance reduces sample prep work and thus provides convenience for its potential use as a field-Based ionization source. These versatilities all come on a small platform. It all started with Marcus and co-workers, who have developed a liquid sampling-atmospheric pressure glow discharge (LS-APGD) as a low power, small footprint, and cost efficient ionization source for mass spectrometry. The glow discharge is sustained between the surface of an electrolytic solution (5-50 μL min-1), introduced through a 0.28 mm (i.d.) capillary housed inside a 1 mm (i.d.) metal capillary (with 0.1-1.0 L min-1 helium sheath gas flows between the two capillaries), and a solid stainless steel counter electrode mounted at a 90° angle with discharge currents of <60 mA, and d.c. powers of <50 W. Presented here, the design and fundamental operational aspects of the LS-APGD used as various spectroscopic sources will be demonstrated graphically. Sample analysis involving direct elemental analysis, organometallic speciation and organic compound in liquid solution, and direct surface analysis of solid sample and liquid residue will be presented to further explain the ability of the LS-APGD. It is believed that the LS-APGD ionization source holds a unique position and has great potential to be utilized in many fields of chemical analysis.

Included in

Chemistry Commons