Characterization of a Pulsed Glow Discharge Laser Ablation System Using Optical Emission

Abstract

Investigations involving laser-based sampling of copper into an auxiliary pulsed glow discharge for ionization and excitation are presented. The interaction of the ablated copper with the auxiliary glow discharge was studied by monitoring the copper atom emission signal at 368.744 nm. Results demonstrate the ability to time ablation appropriately to access specific temporal regions of the pulsed plasma. More specifically, laser-ablated material was introduced into the glow discharge negative glow during the afterpeak. Ionization and excitation was accomplished by collisions with a metastable argon population produced by the glow discharge (Penning ionization) followed by recombination to yield excited-state Cu atoms. The work presented investigates parameters that affect the atomic emission signal intensity of the ablated material, including cathode-to-target distance, discharge gas pressure, and relative timing of discharge and ablation. Results demonstrate that decreasing the glow discharge working gas pressure increases the transport efficiency of laser-ablated material into the negative glow. These investigations are part of an ongoing series of studies on sample introduction schemes that utilize different ionization and excitation mechanisms found in pulsed glow discharge plasmas.

Peer Reviewed: Pulsed Glow Discharge: Temporal Resolution in Analytical Spectroscopy

“…Majidi and co-workers have shown the advantages of this approach for selective excitation of analyte atoms. They also de monstrated that the pressure of the GD source significantly affects results by influencing mass transport as diffusion is slowed by the higher collision rates at increased pressure (16). Double-pulsed GD.…”

A laser ablation millisecond-pulsed glow discharge time-of flight mass spectrometer (LA-GD-TOFMS) for quasi-simultaneous elemental and molecular analysis

“…11,27 Over the last few years, several groups have also examined the possibility of analyzing solids using laser ablation (LA) based GD-setups in combination with atomic emission detection. 28,29,30,31,32,33 Here, the GD acts as a secondary excitation or ionization source for the ablated material permitting to analyze both conducting and insulating materials which, otherwise, can only be accomplished by rf GDs or by preparation of a conductive pellet. Recently, Shelley et al have reported on a LA system coupled to a flowing atmospheric pressure afterglow.…”

Inorganic mass spectrometry as a tool for characterisation at the nanoscale

“…Furthermore, the sampling and ionisation steps are spatially and temporally separated and, thus, can be independently optimised. At present, such a combination is almost unexplored [64][65][66]. Tarik et al [66] have recently investigated the analytical capabilities of LA coupled with pulsed GD-TOFMS.…”