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Gas-Phase Acid-Base Properties And Conformations Of Oligopeptides Through Mass Spectrometry And Computational Studies, Yuntao Zhang

University of the Pacific Theses and Dissertations

This dissertation presents a comprehensive study of the peptides of interest to deeper understand the gas-phase acid-base properties in relation to their conformations and chirality. In the first part of the study, two pairs of alanine (A)-based isomeric peptides consisting of a basic probe, lysine (Lys) or 2,3-diaminopropionic acid (Dap), were investigated to understand the nature of the enhanced basicity when the basic probe was moved from the N-terminus to the C-terminus. In the second part of the study, alanine-based peptides containing a cysteine (C) as the acidic probe were investigated to understand the chirality effects on the gas-phase acidity …

Evaluating Methods Of Obtaining Male Pheromone From Hymenochirus Sp. Using Analytical Chemistry, Vincent Wing-Kun Leung

University of the Pacific Theses and Dissertations

Male Hymenochirus sp. frogs are known to release pheromone that attracts females of the same species. Four methods for collecting secretions containing pheromone in Hymenochirus sp. were tested: norepinephrine injection, gonadotropin-releasing hormone injection, homogenization of gland tissue, and electrostimulation of the skin over the breeding gland area. The samples collected were analyzed using high-performance liquid chromatography (HPLC) and mass spectrometry. The HPLC chromatograph for the male norepinephrine sample contained a peak at 6.4 min that was not in the female norepinephrine sample HPLC chromatograph. The male norepinephrine sample mass spectrum had a peak of m/z 292.0 not in the female …

Roaming Transition States And Highly Accurate Thermochemistry: A Pepico Study Of Two Small Combustion Systems, Kyle John Covert

University of the Pacific Theses and Dissertations

Two small combustion systems, methyl hydroperoxide (CH₃OOH) and 2-propanol ((CH₃)₂CHOH), were studied using imaging photoelectron photoion coincidence spectroscopy (iPEPICO), which combines photoelectron spectroscopy and photoionization mass spectrometry to detect coincident photoelectron-photoion pairs. In the photon energy range of 11.4–14.0 eV, energy selected CH₃OOH⁺ ions dissociate into CH₂OOH⁺, HCO⁺, CH₃⁺, and H₃O⁺ ions. The lowest-energy dissociation channel is the formation of the cation of the smallest “QOOH” radical, CH₂OOH⁺. A statistical rate model fitted to the …

An Investigation Of The Feasibility Of Making Radiometric Titrations Of Precipitation Reactions, Harold Elmore Hammerstrom

University of the Pacific Theses and Dissertations

The purpose of the present work was to (1) determine the feasibility of performing radiometric titrations using low activity radioisotopes and inexpensive equipment; (2) develop a workable procedure for performing ·radiometric titrations in the classroom; and (3) assemble the basic radioactive concepts needed so the content could be used in a chemistry course of study.

The limited work done previously with radiometric titrations has used solutions of high specific activity and relatively large volumes of solution. The use of high activity radioisotopes creates problems of radioisotope procurement, shielding, handling and disposal. The use of high activity radioisotopes required special training …

Fluorescein As A Reagent In A Spectrophotometric Determination Of Micro-Amounts Of Iodine: Application To Glucose Determination, Donald Eugene Braun

University of the Pacific Theses and Dissertations

The increasing awareness of the close inter-relationships between biological activity and chemical reactions has resulted in a rapidly growing pursuit of biochemical knowledge. Research in the related fields of medicine, virology, pharmacy, and biophysics is expanding at a rapid rate. Problems related to food production for an exploding population, space explorations, world health issues, the utilization of the resources of the oceans, and the proper employment of energy sources have spurred man to delve deeper into the secrets of creation. The mysteries of life itself are slowly being revealed through finding in egentic studies.

With this ever expanding biochemical and …

Thin Layer Chromatography Of The Platinum Metal Ions, Anthony Paul Trujillo

University of the Pacific Theses and Dissertations

Recent work in this laboratory has centered about the platinum metals and their complexes. The current activity in thin layer chromatography, and especially the work of Seiler in using the technique for inorganic applications, led to speculation regarding the separation and identification of the platinum metal ions by thin layer chromatography. Specifically, then, the purpose of this study was twofold: (1) to find a suitable adsorbent and solvent system to separate some or all of the platinum metal ions; (2) to find appropriate locating agents, so that once the separation had been accomplished, the ions could be identified.

Controlled-Potential Polarography In Liquid Ammonia: Inorganic Half-Wavepotentials, Ronald Alan Head

University of the Pacific Theses and Dissertations

The literature of polarography is so vast that any new publication in the field is likely to have an impact comparable to that of a raindrop falling on an ocean. If, however, through some alchemy of the imagination, the raindrop transformed to quicksilver and accompanied by discharge of "lightning"; and the "ocean" be a solution under carefully controlled conditions, then the effect may be measurable--even reproducible--and thus subject to rational interpretation. Since Jaroslav Heyrovsky's pioneer work in the early nineteen twenties, many such drops have fallen, bringing the science and art of polarography to its present highly developed state. Though …