Abstract
Optimization of nano-porous ion emitters for uranium analysis by thermal ionization mass spectrometry
American Geophysical Union Fall Meeting, Vol.2023
American Geophysical Union 2023 fall meeting
12/2023
Abstract
Actinide isotope analyses at ultra-trace levels are of great interest for nuclear safeguards and geological applications. While thermal ionization mass spectrometry (TIMS) has been widely used for its sensitivity and precision, its capabilities rely heavily on the analyte ionization efficiencies and analyte loading methods. Our previous efforts on metal organic frameworks (MOFs) as nano-porous ion emitters (nano-PIEs) have shown that uranium sample utilization efficiency (SUE) can be improved by up to nine times that of the analyte on a bare filament. The MOF-derived nano-PIEs have immense potential to enhance SUEs as MOF frameworks can be systematically engineered into ion emitters. In this study, we further delve into the effects of particle size, pretreatment, and filament ramping procedures to optimize SUEs of uranium at picogram level (= 10 (super -12) g). Types of MOFs (i.e., MOF-74, BTC, ZIF series) were carefully chosen based on their ease of structural and compositional alterations and/or high-density open metal sites. Our experimental results from the selected frameworks show that 1) analyte emission depends on the particle size of MOF and the amount of nano-PIE retained on a filament, 2) thermally degraded or pyrolyzed MOFs are more efficient nano-PIEs, and 3) optimal filament ramping conditions can enhance emission but varies between frameworks. Thus far, the nanocrystals of Zn-MOF-74 have yielded up to 1% SUEs with negligible sample loading blanks of <2 fg.
Details
- Title: Subtitle
- Optimization of nano-porous ion emitters for uranium analysis by thermal ionization mass spectrometry
- Creators
- Ji-Hye Seo - Pacific Northwest National LaboratoryDushyant BarpagaAbhishek KumarKyle MakovskyMichael A. SinnwellEirik J. KrogstadKelly McHugh
- Resource Type
- Abstract
- Publication Details
- American Geophysical Union Fall Meeting, Vol.2023
- Conference
- American Geophysical Union 2023 fall meeting
- Publisher
- American Geophysical Union
- Alternative title
- AGU 2023 fall meeting
- Language
- English
- Date published
- 12/2023
- Academic Unit
- Chemistry
- Record Identifier
- 9984966536502771
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