Liquid Chromatography: Injection Broadening in Ion Chromatography and Retention Properties of a New Hydrophilic Interaction Liquid Chromatography Stationary Phase

• Author / Creator

  Zhang, Ya

• Ion Chromatography (IC) is a powerful technique in the separation and analysis of inorganic ions and small charged organic molecules. Meanwhile, Hydrophilic Interaction Liquid Chromatography (HILIC) enables the separation of polar hydrophilic compounds. Although their retention mechanisms are different, the same goal applies. Chromatographers want a fast and thorough separation. This thesis focuses on improving separations in both modes.
  Injection solvent mismatch in Reversed Phase Liquid Chromatography (RPLC) leads to peak broadening and even distortion. In this thesis, systematic studies on IC columns showed that the characteristics of injection solvent mismatch broadening are very different than in RPLC. Also, IC is much more tolerant to high matrix concentration. The sensitivity parameter for evaluating RPLC injection solvent response was applied in the IC column studied for the comparison and can be further used in evaluating other IC columns. In modern IC, suppressors are widely used. Injection system peaks are usually neglected because they are eliminated by the suppressor. However this thesis showed that the system peak strongly affects the nearby analyte peak shape and retention.
  Porous Graphitic Carbon (PGC) is popular in some RPLC applications due to its excellent pH and temperature stability. This stability would also be attractive for HILIC applications. However, the hydrophobic character of PGC makes it incompatible with HILIC separations. In this thesis, PGC was converted into a hydrophilic phase by attaching acetanilide to the surface. The new Amide-PGC shows unique selectivity among 37 stationary phases under HILIC mode. The thesis demonstrates its potential in separating nucleobases, carboxylic acids and pharmaceuticals. Retention is shown to be due to both HILIC partitioning and adsorption on the PGC surface.
  In summary, this thesis improves liquid chromatography in two aspects: IC separations through an understanding of injection broadening; and HILIC through the development of a new stationary phase which enables unique HILIC selectivity.

• Subjects / Keywords

  • Ion Chromatography
  • HILIC
  • Stationary Phase
  • Injection

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3N01046T

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.