Trace metal detecting sensors for environmental and biomedical applications

Stripping voltammetry (SV) is a common technique applied to the detection of trace metals because it is fast, sensitive, and inexpensive. These advantages of SV may be combined with spectroscopy to develop a novel sensor for trace metals in environmental samples. Additionally, SV has not been extended to the analysis of biological samples. However, this technique could be very advantageous especially for samples containing trace metals. My research has focused on developing sensors that utilize SV in sensing for trace metals in both of these applications.; Monitoring trace metals in environmental samples requires methods that are highly sensitive and selective due to the presence of many other analytes at far greater concentrations. Attenuated total reflectance (ATR) spectroscopy has been combined with SV to develop a single sensor for trace metals. Optically transparent indium tin oxide (ITO) electrodes are used to electrodeposit the metals, and absorbance measurements are made as metals selectively strip off ITO at their characteristic stripping potentials. Detection of lead and mercury on a single sensor has been demonstrated. Several key variables affecting analytical performance of the sensor are characterized and optimized including microscopic analysis of metals deposited on the sensor surface by ESEM.; Recent developments in the treatment of severe cases of diabetes involve transplantation of pancreatic islets. The isolation of islets from the pancreas is still in the developmental stages with many variables requiring optimization. Two major issues needing to be addressed are: (1) development of simulants for use in optimizing islet isolation instead of wasting precious islets and (2) development of a better method to monitor the quality of isolated islets prior to transplantation. A key requirement in the development of simulants for pancreatic islets is the ability to mimic secretion behavior observed in glucose stimulated islets. Simulants were therefore developed using agarose beads derivatized with iminodiacetic acid and were qualitatively compared with pancreatic islets. A better detection method for monitoring secretion of insulin was also developed utilizing SV. Zinc secreted from stimulated islets was detected using bismuth modified electrodes.