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dc.rights.licenseRestricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.
dc.contributorShelley, Jacob T., 1984-
dc.contributorMcGown, Linda Baine
dc.contributorDinolfo, Peter
dc.contributorSchaller, Morgan F.
dc.contributor.authorMacLean, Garett Michael
dc.date.accessioned2021-11-03T09:22:41Z
dc.date.available2021-11-03T09:22:41Z
dc.date.created2021-02-22T15:33:59Z
dc.date.issued2020-08
dc.identifier.urihttps://hdl.handle.net/20.500.13015/2633
dc.descriptionAugust 2020
dc.descriptionSchool of Science
dc.description.abstractCurrent research explores the use of the solution-cathode glow discharge (SCGD) as a compact ionization source for elemental and isotope-ratio measurements. Originally, the SCGD was developed as an inexpensive alternative to ICP for optical emission spectroscopy with comparable analytical capabilities. The SCGD consists of a low-power (70 W), direct-current plasma between a metal anode and the surface of a flowing, conductive sample solution with ambient air serving as the discharge gas. The SCGD does not require cooling, nebulization, or external gases for plasma operation, which reduces operational costs and makes the source more amenable to transportable/fieldable analyses.
dc.description.abstractMass spectrometry (MS) has been instrumental for the analysis of elemental species in numerous situations, such as heavy metal contaminants in the environment and isotope-ratio assays in nuclear safeguards. Measurement of elements and their isotopes by MS are some of the most established analytical methods in the field. There have been countless advances in MS, and ionization sources for MS, which have improved detection limits and measurement uncertainties. However, developments in elemental MS typically improve upon preexisting instrumentation and continue to have a number of disadvantages. Some of the disadvantages of these instruments include physical size, high operational costs, excessive power requirements, extensive sample preparation, and complex sample-introduction approaches. Prime examples are the widely used inductively coupled plasma MS (ICP MS) instruments that requires extensive external cooling as well as more than 15 L min-1 of argon and 10 kW of power. Another example includes thermal ionization MS (TIMS) which has lower sample throughput than ICP MS and necessitates extensive sample preparation procedures to attain matrix free samples. However, organizations like the International Atomic Energy Agency (IAEA) that monitors the enrichment of uranium worldwide would also greatly benefit from an inexpensive, rapid and transportable methods for on-site elemental and isotope-ratio analyses.
dc.description.abstractOptimization of the SCGD for elemental analysis has enabled limits-of-detection obtainable in the low parts-per-trillion (pg/mL) for numerous elements. Further method developments have resulted in 235U/238U precisions as low as 0.06% relative standard deviation (RSD) for a 1 part-per-million U-solution of ca. 0.322% 235U abundance within a few minutes of measurement time. For comparison, the precision International Target Value (ITV), published by the IAEA, for natural-abundance uranium (0.3%< 235U< 1%) isotope-ratio assay with MC ICP MS and TIMS is 0.20% RSD. The analytical performance attained has demonstrated that SCGD MS is capable of exceeding the IAEA’s ITVs for established techniques, and shows great promise as a transportable ionization source for on-site isotope-ratio measurements.
dc.description.abstractAs part of the concerted strides in the development of a transportable system, the SCGD has been coupled with additional instruments that utilize mass analyzers more amenable to miniaturized systems, such as linear ion traps and quadrupoles. Additionally, the development of a closed sample introduction system has resulted in a significant decrease in the amount of sample required for analysis and, more importantly the volume of generated waste, with negligible impact on analytical performance. Overall, this research has advanced the understanding of the SCGD as an ionization source for elemental and isotope-ratio mass spectrometry while demonstrating that it is capable of being a competitive, inexpensive, and transportable alterative to current laboratory based instrumentation.
dc.description.abstractHere, a flowing atmospheric pressure afterglow (FAPA) ionization source was utilized for elemental mass spectrometry. The FAPA is a low power (<12 W) plasma based ionization source that utilizes >2 L min-1 of helium. The FAPA enables direct and rapid analyses of gaseous, liquid and solid samples with minimal sample preparation. Typically, the FAPA has been utilized for desorption/ionization of small organic species while only a few examples have explored the sources capabilities for elemental analyses. A volatile chelating ligand, acetylacetone, was explored to aid desorption/ionization efficiencies of low vapor pressure elements. With this reactive FAPA MS approach it was possible to detect over 20 elemental species from liquid and solid samples.
dc.language.isoENG
dc.publisherRensselaer Polytechnic Institute, Troy, NY
dc.relation.ispartofRensselaer Theses and Dissertations Online Collection
dc.subjectChemistry
dc.titleElemental and isotope-ratio mass spectrometry with flowing atmospheric pressure afterglow and atmospheric pressure solution cathode glow discharge ionization sources
dc.typeElectronic thesis
dc.typeThesis
dc.digitool.pid180392
dc.digitool.pid180395
dc.digitool.pid180393
dc.rights.holderThis electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
dc.description.degreePhD
dc.relation.departmentDept. of Chemistry and Chemical Biology


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