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Development of Sensors for Detection of Magnesium Metal Corrosion

Ojo, Kolade O
http://orcid.org/0000-0001-6661-7132
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479817251092405

Abstract Details

2016, PhD, University of Cincinnati, Arts and Sciences: Chemistry.
The need to develop electrochemical sensors and analytical methods for studying the corrosion of magnesium and its alloys in vitro, in real-time, as well as detecting magnesium ions during or after the course of corrosion cannot be over emphasized. Thus, this first part of my dissertation focuses on the use of conductivity as an electrochemical sensor for monitoring, in real-time, magnesium corrosion under cell culture conditions, with enhanced (5%) levels of CO2 in a cell culture incubator. Because magnesium metal, when pure or as an alloy, has the ability to biodegrade in aqueous, high chloride-containing environments, it has been attracting significant attention in biomaterials research for use as biodegradable implants for bone repair and other applications. However, the interactions between magnesium metal and surrounding cells and tissues as the metal corrodes need to be studied to ensure adequate biocompatibility for each intended application, because cell death occurs as a result of high local concentrations of the solution soluble corrosion products when magnesium reacts with water, which include Mg2+, alloying products, OH- and H2. Because some of these products are primarily ionic, we evaluated whether a conductivity sensor could be used to monitor magnesium metal corrosion in three physiologically appropriate solutions by detecting the changes in ionic strength in real-time. We demonstrated that this sensor, in combination with a pH sensor, recorded very different patterns of real-time changes in the three solutions, over 48 h. This work was based on a collaboration with Dr. Sarah Pixley and Tracy Hopkins of the Department of Molecular and Cellular Physiology, University of Cincinnati. Current research on altering the corrosion rate of magnesium metals has focused on improving the in vitro tests needed to analyze magnesium metal corrosion rates and identifying new methods of preparing or post-processing magnesium to alter corrosion rates. In this work, we used a conductivity sensor to study and compare the relative corrosion rates of two previously untested magnesium single crystal samples that differed in surface modifications that could alter and change corrosion rates, in serum-containing cell culture medium under cell culture conditions. This second part of this dissertation was also based on a collaboration with Dr. Sarah Pixley and Tracy Hopkins (Department of Molecular and Cellular Physiology, University of Cincinnati), and Dr. Vesselin Shanov (School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati). The third part of this dissertation focuses on another method that has the potential to be used to monitor magnesium corrosion, particularly if the magnesium could be alloyed with trace amounts of cerium. The method explored was cathodic stripping voltammetry (CSV) for determination of Ce3+ using an indium tin oxide (ITO) electrode. Osteryoung square-wave stripping voltammetry (OSWSV) was used for the stripping step. A detection limit of 5.8 nM was found for a 5 min deposition time. Detection of cerium thus has the capacity to be very sensitive, and thus appropriate for analysis of the amounts that might be released from a magnesium alloy that contained a trace amount of cerium.
William Heineman, Ph.D. (Committee Chair)
Ruxandra Dima, Ph.D. (Committee Member)
Sarah Pixley, Ph.D. (Committee Member)
Thomas Ridgway, Ph.D. (Committee Member)
147 p.
Analytical Chemistry
Magnesium; Osmolality; Corrosion; DMEMF12; CSV; Conductivity

Recommended Citations

Citations

  • Ojo, K. O. (2016). Development of Sensors for Detection of Magnesium Metal Corrosion [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479817251092405

    APA Style (7th edition)

  • Ojo, Kolade. Development of Sensors for Detection of Magnesium Metal Corrosion. 2016. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479817251092405.

    MLA Style (8th edition)

  • Ojo, Kolade. "Development of Sensors for Detection of Magnesium Metal Corrosion." Doctoral dissertation, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479817251092405

    Chicago Manual of Style (17th edition)

ucin1479817251092405
339
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This open access ETD is published by University of Cincinnati and OhioLINK.