Graduation Year


Document Type




Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department


Major Professor

Theresa Evans-Nguyen, Ph.D.

Committee Member

Andreas Muller, Ph.D.

Committee Member

Abdul Malik, Ph.D.

Committee Member

Xiaopeng Li, Ph.D.


Quadrupole Ion Trap, Digital Ion Trap, Static Buffer Gas Introduction, Pulsed Buffer Gas Introduction, Isotope Ratio Mass Spectrometry, Selective Isotope Enrichment, Electron Impact Ionization, Chemical Ionization, Mass Selective Instability, Resonance Ejection


Ion trap mass spectrometers present a powerful analytical tool which not only enables mass spectrometric determination of analyte species but also has the added feature of being able to act as an ion storage device. As a mass spectrometer, ion traps can achieve a reasonable mass range with flexible mass resolution while boasting a considerably smaller footprint when compared to conventional time-of-flight or magnetic sector instruments. Due to their smaller geometries, high-pressure tolerance, and ability to perform tandem mass spectrometry, ion trap mass spectrometers are ideal candidates for portable applications such as deployment to another planetary body. While ideal candidates for portable applications, ion traps are limited in the number of ions they can store due to space charge effects that arise from ion-ion repulsions thereby limiting the utility of these instruments. Additionally, effects of size, weight and power must also be considered when developing a portable instrument. For the following chapters, the focus will be on the optimization of an ion trap mass spectrometer for the targeted application of isotope ratio mass spectrometric measurements of xenon. Initially, a novel means of improving resolution and total ion signal through precision control of the buffer gas introduction was developed. We then explored how the data acquisition system can be modified to improve accuracy and precision in our isotope ratio measurements. Finally, a method of selective enrichment and chemical ionization was studied to determine if xenon could be selectively extracted over other atmospheric gases and chemically ionized using argon as a reagent gas.