Description
Recently, the US experienced a rising concern over toxic pollution of drinking water from heavy metal sources. Often, heavy metals find their way into water supplies for local communities which results in the indirect poisoning of people. Therefore, there is great need for a commercially available and portable device which would provide an easy method to test the level of poisonous elements in community water supplies. In this thesis, the design, microfabrication, and characterization of a novel microfluidic device for the measurement of trace lead ions is described. The work presented focuses on these ions due to their health hazards and low concentration limits lending to an interesting challenge in detection. The first effort in this project revolved around determining the form factor of a micro-device which acts as an environmental sensor for minute concentrations of lead. Much background research into similar devices was performed before starting to conceptualize the preliminary design. Taking the equipment of the San Diego State University Clean Room facility into consideration, a rough model was presented and refined over several weeks. A final design then followed with a basic 3D model and fabrication process presented. After much time testing and redesigning, results were generated for the measurement of 2.53 μg/L of trace lead ions in a solution of water. This showed a detection limit less than the Environmental Protection Agency’s maximum safe standard of 15 μg/L for lead. The device also represented an improvement over other similar literature sources, most of which had limits of detection greater than 14 μg/L. Additional fabrication outcomes and surface characterization studies resulting from this investigation are also presented. Finally, the practicality of the device is studied and suggestions are made for future work.
