Date of Graduation

Summer 2021


Master of Science in Chemistry



Committee Chair

Erich Steinle


ion selective electrode, ionophore, metalloporphyrin, tetraphenylporphyrin, chromatography, spectroscopy

Subject Categories

Analytical Chemistry


Ion selective electrodes (ISEs) are analytical sensors that monitor the interactions between an ionophore within a polymeric membrane and ions in various solutions. The sensitivity and selectivity of ISEs is directly related to the chemical components. One type of ionopohore utilized in ISEs are metalloporphyrins. Metalloporphyrins have unique binding characteristics, which make them useful in sensors. The polymeric membranes that are synthesized and used in ISEs consist of a metalloporphyrin complex, polyvinyl chloride, and ortho-nitrophenyl octyl ether. The membrane unique to this project contains erbium (III) tetraphenylporphyrin as the metalloporphyrin ionophore. Various analytical techniques were applied in the investigation of the reactivity and chemical characteristics of the metalloporphyrin complex within the membrane and in solutions. These techniques included gas chromatography, gas chromatography-mass spectrometry, ultraviolet-visible spectroscopy, and fluorescence spectroscopy. In this work, the optical properties of the erbium porphyrin complex, including major absorption and emission wavelengths, were examined. The applicability of several chromatographic techniques was also studied. The reactivity of the metalloporphyrin within the polymeric membrane was measured directly upon exposure to variable concentrations of the target analyte. In the future, the plan is to further investigate spectroscopic techniques such as fluorescence and the potential use of porphyrins in fluorescent indicators, much like the ISEs. The goal is to expand the knowledge of the porphyrin’s reactivity to improve the sensitivity and selectivity of ion selective electrodes.


© Alexis Rae Miller

Open Access