Garrett Smith

Date of Graduation

Summer 2012


Master of Science in Chemistry



Committee Chair

Erich Steinle


ion-selective electrode, ionophore, Erbium, metalloporphyrin, lactate, salicylate, citrate

Subject Categories



Ion selective electrodes provide for an analytical technique which has applications in many different areas of chemistry. One of the most well-known ion selective electrodes to have found commercial use is that of the pH electrode. These instruments work by creating a potential across a membrane at the end of the electrode. This potential is then measured against a reference electrode and allows for the measurement of concentrations of a target species in solution. One of the main components of the ion-selective electrode is in the choosing of the ionophore to include in the matrix of the membrane. The ionophore is what provides the specificity in the selection of your target species. The lanthanide series of metals in the periodic table have remained one of the least investigated groups of metals for their applications as ionophores in ion-selective electrodes. The lanthanide metal Erbium has presented itself as a viable metal for use in these electrodes. When a Erbium(III) metalloporphyrin has been utilized as an ionophore, it has consistently shown affinity for anions that specifically contain a carboxylate functional group. This study examines the response of these electrodes to carboxylate anions of variable carbon-chain length in depth. Initial results indicate that lipophilicity may not be much of a factor in electrode sensitivity. Also, the response of the Erbium(III) metalloporphyrin-based electrodes to common anions such as lactate and citrate is determined.


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