Liquid Sampling–Atmospheric Pressure Glow Discharge as a Secondary Excitation Source for Laser Ablation-Generated Aerosols: Parametric Dependence and Robustness to Particle Loading

Liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma is being developed as a secondary vaporization-excitation source for the optical emission analysis of laser ablation (LA)-generated particle populations. The practicalities of this coupling are evaluated by determining the influence of source parameters on the emission response and the plasma's robustness upon LA introduction of easily ionized elements (EIEs). The influence of discharge current (45-70 mA), LA carrier gas flow rate (0.1-0.8 L min−1), and electrode separation distance (0.5-3.5 mm) was studied by measuring Cu emission lines after ablation of a brass sample. Best emission responses were observed for high-discharge currents, low He carrier gas flow rates, and relatively small ( 10 W mm−3) of the LS-APGD microplasma.