Open Access Thesis
Master of Science (MS)
Donald Snyder, PhD, Chair
Timothy Brewer, PhD, Committee Member
Heather Holmes, PhD, Committee Member
Abstract Recent work has provided evidence that 5-amino-1, 10 –phenanthroline can react with CS2 to anchor on the gold surface of an interdigitated electrode (IDE) through a dithiocarbamate linkage, resulting in significant changes in impedance response in the presence of Cu2+ solutions. However, questions regarding the stability of the primary amine-based dithiocarbamate self-assembled monolayer, reproducibility of the raw impedance and phase angle data, and possible variation of the background response for the gold IDE array in solutions of different metal ions remain an issue. Primary experimental emphasis is on the reproducibility of standard impedance and phase angle data for the underivatized gold interdigitated electrode (IDE) in water, Cu2+ and Mg2+ solutions of varying concentrations. Results of these experiments indicate that the change in impedance and the phase angle are dependent on ionic concentrations, but that the change is independent of the nature of the ions. The limit of detection and linearity range for Cu2+ vs. Mg2+ were determined for untreated IDE array with no significant difference. After a literature search a procedure was developed to prepare a dithiocarbamate monolayer on the gold IDE using 5-amino-1, 10-phenanthroline with CS2 in methanol. The initially formed SAM was detectable by comparison of its impedance curve with the blank, but adherence to the chip was inadequate to resist removal under aqueous conditions. Comparison with previous work indicates that proper deposition of the dithiocarbamate SAM is more dependent on the preparation process than expected.
Yalamanchili, Sindhu, "Comparison of standard impedance spectroscopy response to aqueous metal ions using plain vs. surface derivatized gold interdigitated electrodes" (2011). Master's Theses and Doctoral Dissertations. 353.