Implementation of Solution and Solid Sate Nuclear Magnetic Resonance (NMR) Spectroscopic Techniques for Quantitative and Qualitative Analysis of Molecular Species

Title from PDF of title page viewed May 19, 2020Dissertation advisor: Nathan A. OylerVitaIncludes bibliographical referencesThesis (Ph.D.)--Department of Chemistry and Department of Physics and Astronomy. University of Missouri--Kansas City, 2019In this dissertation, spectroscopy has been used to solve a variety of problems in different domains of science. Therefore, each chapter consists of different examples that have been addressed using different concepts of spectroscopy. The objective of part I (application of solution state NMR spectroscopy in pharmaceutical sciences) is to apply NMR techniques in different pharmaceutical projects. In chapter3, a real-time quantification of in vitro Bortezomib (BTZ) release from alginate microparticles using a solution state quantitative boron nuclear magnetic resonance (11B qNMR) method is presented. The method was validated according to International Conference on Harmonization (ICH) guidelines. Therefore, several analytical performance parameters were discussed such as limit of detection (LOD), limit of quantification (LOQ), linearity, specificity, accuracy, precision and robustness. The 11B qNMR method was applied to the in vitro release study of a model drug, bortezomib (BTZ) from alginate microparticles and results were compared to a commonly used dialysis method. Throughout the release study, the dialysis method consistently underestimated the level of drug released, probably due to the separating membrane that can interfere with the real-time drug transport process. Overall, compared to the dialysis method, the direct 11B qNMR method was accurate and provided a direct and real-time quantification of BTZ for an effective study of drug release kinetics. Similarly, in chapter 4, a 19F qNMR method was developed and validated and then applied to study the real-time release of maraviroc from a microparticle formulation in a vaginal and seminal stimulated environment. Different possibilities were discussed to control the release profile such as the crosslinking process and a pH sensitive polymer. In chapter 5, the project is a collaborative effort between the department of Chemistry and School of Pharmacy. Our contributions in that project are to utilize 11B NMR spectroscopy technique as a characterization tool for the reaction progression. Moreover, to perform theoretical and experimental calculations and compare them to each other in order to trace the reaction mechanism. The overall motivation of the project is to test an assumption about phenylboronic acid (PBA) to prevent HIV transmission. It has been found that phenylboronic acid can form boronic acid in the presence of cis-diol, like the one found in HIV-gp120 glycoproteins. In order to exam the proposed hypothesis, a derivative of phenylboronic acid was synthesized. The synthetic scheme and the spectroscopic results are presented and discussed in detail. The objective of part II (applications of solid-state NMR spectroscopy) is to apply SSNMR spectroscopy experiments in two projects to gain significant information about specific materials. In chapter 6, some main concepts of SSNMR spectroscopy are discussed as well as some basic SSNMR experiments. In chapter 7, boron carbide thin films were grown using plasma enhanced chemical vapor deposition (PECVD) under different growth conditions. Different possible spectroscopic techniques were discussed in order to discover the local physical structure of boron carbide thin films. However, most of these techniques have shown a lack of an ability to demonstrate the internal structure of thin films. SSNMR spectroscopy was successfully employed to reveal information about the internal structure of boron carbide thin films. In chapter 8, the optical properties of titanium oxide TiO2 were modified by introducing a hydrazine molecule. SSNMR spectroscopy was implemented to monitor the reaction progression of TiO2 to improve its optical properties.Introduction -- Applications of soultion state NMR spectroscopy in pharmaceutical sciences -- Applications of solid-state NMR spectroscop

Surface Modification of PP and PBT Nonwoven Membranes for Enhanced Efficiency in Photocatalytic MB Dye Removal and Antibacterial Activity

In this study, we developed highly efficient nonwoven membranes by modifying the surface of polypropylene (PP) and poly(butylene terephthalate) (PBT) through photo-grafting polymerization. The nonwoven membrane surfaces of PP and PBT were grafted with poly(ethylene glycol) diacrylate (PEGDA) in the presence of benzophenone (BP) and metal salt. We immobilized tertiary amine groups as BP synergists on commercial nonwoven membranes to improve PP and PBT surfaces. In situ Ag, Au, and Au/Ag nanoparticle formation enhances the nonwoven membrane surface. SEM, FTIR, and EDX were used to analyze the surface. We evaluated modified nonwoven membranes for photocatalytic activity by degrading methylene blue (MB) under LED and sunlight. Additionally, we also tested modified membranes for antibacterial activity against E. coli. The results indicated that the modified membranes exhibited superior efficiency in removing MB from water. The PBT showed the highest efficiency in dye removal, and bimetallic nanoparticles were more effective than monometallic. Modified membranes exposed to sunlight had higher efficiency than those exposed to LED light, with the PBT/Au/Ag membrane showing the highest dye removal at 97% within 90 min. The modified membranes showed reuse potential, with dye removal efficiency decreasing from 97% in the first cycle to 85% in the fifth cycle

Photochemical Synthesis of Noble Metal Nanoparticles: Influence of Metal Salt Concentration on Size and Distribution

This paper explores the photochemical synthesis of noble metal nanoparticles, specifically gold (Au) and silver (Ag) nanoparticles, using a one-component photoinitiator system. The synthesis process involves visible light irradiation at a wavelength of 419 nm and an intensity of 250 mW/cm2. The radical-generating capabilities of the photoinitiators were evaluated using electron spin resonance (ESR) spectroscopy. The main objective of this study was to investigate how the concentration of metal salts influences the size and distribution of the nanoparticles. Proposed mechanisms for the photochemical formation of nanoparticles through photoinitiated radicals were validated using cyclic voltammetry. The results showed that the concentration of AgNO3 significantly impacted the size of silver nanoparticles, with diameters ranging from 1 to 5 nm at 1 wt% and 3 wt% concentrations, while increasing the concentration to 5 wt% led to an increase in the diameter of silver nanoparticles to 16 nm. When HAuCl4 was used instead of AgNO3, it was found that the average diameters of gold nanoparticles synthesized using both photoinitiators at different concentrations ranged between 1 and 4 nm. The findings suggest that variations in HAuCl4 concentration have minimal impact on the size of gold nanoparticles. The photoproduction of AuNPs was shown to be thermodynamically favorable, with the reduction of HAuCl4 to Au0 having ∆G values of approximately −3.51 and −2.96 eV for photoinitiators A and B, respectively. Furthermore, the photoreduction of Ag+1 to Ag0 was demonstrated to be thermodynamically feasible, with ∆G values of approximately −3.459 and −2.91 eV for photoinitiators A and B, respectively, confirming the effectiveness of the new photoinitiators on the production of nanoparticles. The synthesis of nanoparticles was monitored using UV-vis absorption spectroscopy, and their sizes were determined through particle size analysis of transmission electron microscopy (TEM) images