Development of Solid Sampling Modalities for the Liquid-Sampling Atmospheric Pressure Glow Discharge Microplasma
Date of Award
Doctor of Philosophy (PhD)
Richard K. Marcus
Fast pretreatment of samples, low resource consumption, and high analytical throughput makes direct solid sampling techniques an attractive choice for a wide range of applications. Currently there are a plethora of analytical techniques capable of solid sampling. However, no commercial technique is available that is capable of taking advantage of the key concepts of solid samplings. General disadvantages amongst the current solid sampling instrumentation are high cost of operation, limited analyte choice, and reduced analytical performance. In that regard, it is important to develop a source that has low operation cost as well as the capability to analyze a diversity of analytes. An added benefit would be if the source is comparable in analytical performance to that of solution based instruments. One potential source is the liquid sampling – atmospheric pressure glow discharge (LS-APGD) microplasma that is utilized primarily for solution analysis.
The analytical merits of the LS-APGD overlaps with that of direct solid sampling. The LS-APGD provides a multi-faceted approach to analytical instruments by providing a variety of information from a compact ionization/excitation source. Unique amongst the tools in the analytical toolbox, the LS-APGD is capable of not only ionizing elements but also molecular species. Beyond that, the LS-APGD also operate in a total consumption mode, i.e no solvent waste, with solution flow rates under 100 µL min-1 as well as less than 1.0 L min-1 of helium gas flow. These analytical merits of low cost and abundance of information coincide with the key advantages of direct solid sampling. Presented in this dissertation is efforts on adding and improving solid sampling modalities to this ionization/excitation source. The dissertation discusses the influence of plasma parameters on optical emission though ambient desorption as well as the implication of those trends on underlying mechanism. On the sample preparation side, an effective means of preparing residues for analysis via intelligent substrate choice as well as co-adding dopant is provided. Finally, two sampling methods coupled to the LS-APGD is described. A novel solvent extraction method for heat sensitive samples as well as coupling to a laser ablation system for comprehensive atomic, molecular, and spatial analysis.
Paing, Htoo, "Development of Solid Sampling Modalities for the Liquid-Sampling Atmospheric Pressure Glow Discharge Microplasma" (2020). All Dissertations. 2676.