Date of Graduation

Fall 2014

Degree

Master of Science in Chemistry

Department

Chemistry

Committee Chair

Erich Steinle

Keywords

ion selective electrode, ionophore, tetraphenylporphyrin, Holmium, Ytterbium, calibration, detection limit, selectivity coefficient

Subject Categories

Chemistry

Abstract

Previous work using lanthanide metalloporphyrins as ionophores in liquid/polymer membrane ion selective electrodes (ISEs) has shown promising results. Erbium(III) and lutetium(III) tetraphenylporphyrin have shown selectivity for salicylate anion and. New work with previously unexamined holmium (III) and ytterbium (III) tetraphenylporphyrin-based ISEs was begun to determine any similarities or differences in response and selectivity throughout the lanthanide series. Initial calibration curves were experimentally created towards the Hofmeister series of anions and show unique response patterns for each membrane with 20 mole% cationic additive. Detection limits and Nernstian ranges were determined from these calibration curves. Potentiometric selectivity coefficients of these ISEs were calculated by comparing electromotive force (EMF) responses of a primary ion, chloride, versus a variety of interfering ions. Results showed that a membrane consisting of 20 mole% of cationic additive provided the greatest selectivity of these sensors towards salicylate.

Copyright

© Johnathon H. Hoskins

Campus Only

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