Yadi Wang

ORCID Identifier(s)


Graduation Semester and Year




Document Type


Degree Name

Doctor of Philosophy in Chemistry


Chemistry and Biochemistry

First Advisor

Daniel W Armstrong


The use of high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) is now commonplace among pharmaceutical laboratories. They are major analytical tools in the drug discovery process. They are used to check the identity and the purity of newly synthesized compounds as well as to follow the reaction processes. They are also utilized to monitor the concentration of a drug in different biological matrices. In this thesis, fundamental contributions to HPLC and LC-MS bioanalysis work are discussed. The goal of the HPLC work is to develop a hydrolytically stable hydrophilic interaction liquid chromatography (HILIC) stationary phase. A carboxylate modified cyclofructan 6 was bonded onto superficially porous particles and was shown to have high hydrolytically stability. The stationary phase provided fast separation and unique selectivities compared to commercially available columns. The carboxylated CF6 simultaneously separated acidic, neutral and basic drugs and produced considerably different retention and selectivity patterns for various classes of compounds including nucleic acid bases, β blockers, salicylic acid and its derivatives. The goal of the remaining part of this thesis is to demonstrate the application of HPLC-MS for the analysis of glycosaminoglycan disaccharides and amino acids. For the analysis of glycosaminoglycan disaccharides, fast and sensitive methods were developed using two HILIC stationary phases for disaccharides following the enzymatic digestion of glycosaminoglycan. For the achiral analysis of amino acids, a sensitive detection method based on paired ion electrospray ionization was developed for the analysis of FMOC-amino acids in biological samples. This method showed improved detection sensitivity down to sub-pg level. A simple, rapid and sensitive method was developed by using HPLC-triple quadrupole mass spectrometry for the analysis of D and L-amino acid in various biological matrices, such as mouse brain tissue and cultured human breast cells. The levels of 22 amino acids and their enantiocompositions in the whole brain of wild-type ddY mice and ddY mice lacking DAO were compared. We describe, for the first time, the endogenous levels of free L- and D-amino acids in human breast cancer cells (MCF-7) and non-tumorigenic epithelial breast cells (MCF-10A).


Liquid chromatography, Mass spectrometry, Amino acid


Chemistry | Physical Sciences and Mathematics


Degree granted by The University of Texas at Arlington

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