• Login
    View Item 
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    An Investigation of the Role of Silica Substrate Topography on the Tailing and Broadening of Basic Compounds in HPLC

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_etd_2359_sip1_m.pdf
    Size:
    2.623Mb
    Format:
    PDF
    Description:
    azu_etd_2359_sip1_m.pdf
    Download
    Author
    Legg, Michael Antonio
    Issue Date
    2007
    Keywords
    Chemistry
    Advisor
    Wirth, Mary J
    Committee Chair
    Wirth, Mary J
    
    Metadata
    Show full item record
    Publisher
    The University of Arizona.
    Rights
    Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
    Abstract
    Atomic force microscopy, Fourier transform infrared spectroscopy, high performance liquid chromatography, and UV-vis spectroscopy were used to study commercial and locally produced chromatographic silica substrates. Previous work has correlated the presence of isolated silanols with the peak tailing and broadening of basic analytes, and studies have shown enhanced adsorption of these analytes to isolated silanols at topographic features on planar, fused silica coverslips. This work provides evidence that similar topographical features exist on chromatographic substrates.This work is the first, to our knowledge, to provide nanoscale, topographic data on commercial silica. Three products; by Agilent, Merck, and Waters all have surface features that are similar in size and shape to the features on planar coverslips. The Agilent product also has seams where the individual colloids are fused together to form the bulk particle. These seams may not be fully silylated due to steric hindrance. Neglecting these features, the bulk of the silica surface is as smooth as fused silica.The AFM, FTIR, and HPLC data all indicate that the Waters silica had roughly twice the abundance of isolated silanols as the Merck product. The HPLC data for the Agilent material exhibited fronting and could not be modeled, but the FTIR data indicated that it had the same isolated silanol abundance as the Merck product.These same methods were used to characterize nonporous silica particles produced in our laboratory to be used as substrates for a variety of separation techniques. From the initial silica particles to the final colloidal crystal, AFM, FTIR, and UV-Vis data used to characterize these materials is presented. A method to determine the refractive index of the silica particles was developed and the changes in refractive index as the material is processed are also shown.Separation of three dye species and another separation of three peptide chains was done on a 2D colloidal crystal of these silica particles. The colloidal crystal outperformed a commercial, silica monolithic product both in terms of peak asymmetry and in resolving the analytes. This preliminary work shows the promise of this material as a substrate for chromatographic separations.
    Type
    text
    Electronic Dissertation
    Degree Name
    PhD
    Degree Level
    doctoral
    Degree Program
    Chemistry
    Graduate College
    Degree Grantor
    University of Arizona
    Collections
    Dissertations

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.