Preparation and Characterization of Stationary Phases for Hydrophilic Interaction Liquid Chromatography and Reversed Phase Liquid Chromatography

• Author / Creator

  Iverson, Chad D

• High performance liquid chromatography (HPLC) has become an invaluable tool in modern chemical analysis. While reversed phase liquid chromatography (RPLC) is the most commonly utilized mode of HPLC, hydrophilic interaction liquid chromatography (HILIC) is gaining popularity due to its ability to retain and resolve highly polar analytes that are incompatible with RPLC. Previously, Dr. Mohammed Ibrahim developed a simple and straightforward two dimensional HILIC selectivity plot to characterize the selectivity behavior of HILIC columns. The first part of this thesis expands these plots to examine the changes in selectivity behavior that 19 HILIC columns undergo in response to changes in mobile phase pH and buffer concentration. The second and third research chapters focus on the development of new carbon-based columns for RPLC and HILIC. The vast majority of RPLC and HILIC columns are based on silica particles. Silica is chemically unstable under extreme pH conditions. Porous graphitic carbon (PGC) is an attractive alternative to silica-based phases due to its chemical and thermal stability, and its unique selectivity. However, native PGC is strongly hydrophobic and in some instances excessively retentive. To increase the hydrophilicity of PGC and attenuate its excessive retentivity, diazonium chemistry was utilized to separately modify the surface of PGC with aniline, catechol, and amide groups. The performance of these three new phases (Aniline-PGC, Catechol-PGC, and Amide-PGC) was demonstrated by separations of phenols, nucleotides, nucleosides, carboxylic acids, alkaline pharmaceuticals, and/or performance enhancing stimulants. Notably, the Aniline-PGC and Amide-PGC phases reduced the RPLC retentivity of PGC up to 90 %. Most HPLC methods today use acetonitrile or methanol as the organic mobile phase component. Increasing environmental consciousness (green chemistry) promotes the use of more environmentally sustainable solvents such as ethanol. In the last research chapter, I briefly discuss the feasibility and performance of ethanol as an HPLC eluent, relative to acetonitrile and methanol, in the context of a commentary on a recently published work on “cocktail chromatography”.

• Subjects / Keywords

  • High Performance Liquid Chromatography (HPLC)
  • RPLC
  • HILIC
  • Cocktail Chromatography
  • Porous Graphitic Carbon

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3JD4Q43D

• 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.