Nano-Engineered Electrochemical Sensors for Monitoring of Toxic Metals in Groundwater: Development of Novel Square Wave Anodic Stripping Voltammetry Electrodes Using Self Assembled Monolayers on Mesoporous Supports.

摘要

To remediate groundwater tainted with toxic metal ions such as mercury or lead, it would be advantageous to have ion specific sensors for those ions. This project involved coupling novel sorbent materials known as Self Assembled Monolayers on Mesoporous Supports (SAMMS) with electrolytic probes to allow the detection of mercury, lead, and actinides from aqueous solution using Square Wave Anodic Stripping Voltammetry (SWASV). Electrodes were fabricated using three approaches: embedding the SAMMS in a conductive carbon paste, depositing the SAMMS as a thin film to the face of the electrode, and depositing thin film SAMMS to interdigitated electrodes. Results are presented which demonstrate that these electrodes are a promising selective detection technology. The selectivity of the SAMMS technology coupled with the rapid collection and detection methods afforded by the SWASV technique represent a clear step forward in the development of devices for rapid, fieldable devices for environmental remediation and testing for adherence to water quality standards. The interdigitated electrodes, while a promising idea, did not achieve the desired level of sensitivity; further work would be necessary to advance this technology to a more promising status. The driver for pursuing the interdigitated electrodes is that capacitance can be measured far more precisely than integrated current (as in the SWASV technique); the barrier to success at this juncture would appear to be insufficient sensitivity of the capacitance of the electrodes to the adsorption of the target analytes. Greater capacity for captured analytes in the regions between the intedigitated spokes may address this limitation.