Date of Award
Doctor of Philosophy (PhD)
R. Kenneth Marcus
Kenneth A. Christensen
An increased interest has been placed on the miniaturization of chemical processes. Focus is placed on rapid chemical analysis, decreased operation cost, minimal generation of chemical waste, and reduced sample size. Presented here is an approached the goal of 'miniaturization' through two distinct areas of analytical chemistry: 1) employing capillary-channeled polymer (C-CP) fibers as a stationary phase in micro-SPE (solid phase extraction) tips for the extraction of proteins from buffered solutions (i.e. biofluids) with analysis by mass spectrometry (MS) and 2) the development of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) as an excitation source for elemental analysis. Determination of proteins in biological matrices is vital for the identification of disease-specific biomarkers. With this in mind, research efforts have grown tremendously for protein analysis in biofluids. More importantly, research has focused on development of extraction/separation techniques necessary for performance on miniaturized levels (i.e. low volume aliquots/concentrations) prior to analysis with mass spectrometry (MS). MS is commonly used for detection due to its sensitivity and the abundant chemical information it provides on analysis. However, buffered species (i.e. salts and biofluids) can be detrimental to MS analysis due to mechanisms such as co-ionization. Presented here, is the use of C-CP fibers as a stationary phase for the extraction of proteins from these matrices. These C-CP mirco-SPE tips have shown to be effective for extraction of nanogram quantities of proteins from buffered species. More importantly, extractions have been optimized to be performed with samples sizes of ~1 ÂµL compared to commercially available tips which require up to 100 ÂµL of sample. Investigations of fiber packing density, tip length, loading capacities, and load/elution volumes were performed to improve the efficiency of C-CP tips for the extraction of proteins. After optimization, C-CP tips were utilized for extracting nanogram quantities of proteins (<5 >ÂµL aliquots) from urine matrices. Additionally, there is a need to design spectrochemical instruments with lower power consumption, reduced sample sizes, compact footprint, and the ability to be operated under ambient conditions. In this dissertation the liquid sampling-atmospheric pressure glow discharge (LS-APGD) is employed as a miniaturized approach towards elemental analysis focusing on the determination of plasma characteristics (i.e. plasma temperatures) under parametric evaluations for elemental analysis of solutions and the use of the LS-APGD source as a secondary excitation/ionization source following laser ablation of solid materials. Excitation, rotation, and ionization temperatures along with electron number density and robustness characteristics of the LS-APGD were studied under parametric evaluation. It was determined that the LS-APGD show great promise in terms of handling complex samples (liquid and laser ablated particles) without presenting matrix effects. Both directions demonstrate promising results with regards to miniaturization of chemical analysis techniques in hopes of developing rapid procedures that require small quantities of sample while operating at low costs and producing little to zero chemical waste.
Manard, Benjamin, "Miniaturization of Chemical Analysis Tools: Micro-Solid Phase Extraction Tips for Protein Extractions and Development of a Miniaturized Glow Discharge Source for Elemental Analysis" (2014). All Dissertations. 1397.