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Evaluation of Chromatographic Systems using Green Chemistry Metrics and Development of Molecular Imprinted Sorbents

Fitch, Brian N
http://orcid.org/0000-0003-1126-7117
http://rave.ohiolink.edu/etdc/view?acc_num=osu1629544659546284

Abstract Details

2021, Doctor of Philosophy, Ohio State University, Chemistry.
This dissertation explores applying green chemistry principles to analytical separation and sampling techniques. Green chemistry principles focus on methods to reduce the emissions and waste produced from reactions and chemical related techniques. The principles also encourage the replacement of hazardous or toxic compounds with benign chemicals and solvents whenever possible. In analytical chemistry, this typically means reducing the usage of organic solvent or using separation techniques that do not use hazardous solvents. Green chemistry metrics will be used to determine the greenness of reversed phase high performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) for the separation of pharmaceutical compounds. Common solvents such as acetonitrile and alcohols such as methanol, ethanol, and isopropanol are explored in both chromatographic systems. Life cycle analysis (LCA) and the Analytical Method Greenness Score (AMGS) calculator are utilized as metrics to grade the separations and determine which portions of the separations produced the most emissions. In particular, the relationship between instrument energy consumption, organic solvent usage, and separation time is explored. These are also explored for both the preparative scale and analytical scale. The influence of chromatographic conditions for SFC, such as flow rate and higher back pressure, are shown to improve the greenness for this technique. The potential of SFC to be a greener alternative method than acetonitrile-containing HPLC conditions is shown for a variety of pharmaceutical separations. In addition to chromatographic parameters, electricity sources were explored to show how the relationship between the greenness for HPLC and SFC changes with the greenness of the energy source mix. The high impact of instrument energy for analytical systems shows the importance of reducing instrument run time and not focusing on mobile phase solvents alone. This is particularly true for SFC due to the additional instrumentation required to pressurize carbon dioxide. As energy mixes are likely to become greener over time and less reliant on energy sources, such as coal, the future changes in greenness is explored by using several regional energy mixes. A green renewable energy source is also utilized as a suitable ideal energy source for comparison of HPLC and SFC. The use of a very green energy source significantly reduces the impact from instrument energy consumption and improves the relationship between SFC and HPLC. Finally, electrospun nanofiber solid phase microextraction (SPME) sorbents are molecularly imprinted with two polysulfide malodor compounds. These sulfur compounds are detectable at very low concentrations by humans and are possible side products from the fermentation process of beer. Epoxy and carbon nanofibers are utilized to extract both polysulfide compounds from the headspace of standard solutions. The molecularly imprinted sorbents possess enhanced selectivity for the template compound with the lowest improvement being 18%. The selectivity of the imprint was also shown by using a compound similar to the template, such as dimethyl trisulfide, to compete with the template compound, dimethyl disulfide. The robustness of the imprint is shown as there was little decrease in extraction efficiency after 50 injections.
Susan Olesik (Advisor)
Anne Co (Committee Member)
Abraham Badu-Tawiah (Committee Member)
202 p.
Chemistry
Green Chemistry; Separation Science; HPLC; SFC; SPME; Nanofibers

Recommended Citations

Citations

  • Fitch, B. N. (2021). Evaluation of Chromatographic Systems using Green Chemistry Metrics and Development of Molecular Imprinted Sorbents [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1629544659546284

    APA Style (7th edition)

  • Fitch, Brian. Evaluation of Chromatographic Systems using Green Chemistry Metrics and Development of Molecular Imprinted Sorbents. 2021. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1629544659546284.

    MLA Style (8th edition)

  • Fitch, Brian. "Evaluation of Chromatographic Systems using Green Chemistry Metrics and Development of Molecular Imprinted Sorbents." Doctoral dissertation, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1629544659546284

    Chicago Manual of Style (17th edition)

osu1629544659546284
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This open access ETD is published by The Ohio State University and OhioLINK.