Publication Date
2022
Document Type
Thesis
Committee Members
Steven Higgins, Ph.D. (Advisor); Rachel Aga, Ph.D. (Committee Member); David Dolson, Ph.D. (Committee Member)
Degree Name
Master of Science (MS)
Abstract
In this work, a spectrophotometric titration of methylthymol blue (MTB) with barium chloride was performed at pH = 7.5, 9.6, and 12.2 to determine the stoichiometry of complexation between the two as well as formation constants and absorptivity coefficients. Complexes of 1:1, 2:1, and 3:1 Ba:MTB were suggested by the experimental data upon fitting with appropriate models using Beer’s Law. The molar absorptivities of free MTB species at 605 nm were determined to be ����2������4− = 5.0 (± 0.2) x 103 L·mol-1·cm-1, ����������5− = 7.3 (± 0.3) x 103 L·mol-1·cm-1, ��������6− = 1.3 (± 0.2) x 104 L·mol-1·cm-1. At pH = 9.6, ������2��2������ and the formation constant of that complex were determined to be 6.0 (± 0.2) x 103 L·mol-1·cm-1, and 7 (± 4) x 102, respectively. Similarly at pH 12.2, ������2��������−, and its formation constant were determined to be 8.2 (± 0.1) x 103, and 1.2 (± 0.4) x 102, respectively. Formation constants of 3:1 complexes were unable to be determined with certainty due to a lack of constraints at high barium concentration. Binding activity was largely influenced by barium concentration and pH, presumably due to the dominant species of MTB present in solution.
Page Count
89
Department or Program
Department of Chemistry
Year Degree Awarded
2022
Copyright
Copyright 2022, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
ORCID ID
0000-0003-2541-5029
