Development of a microchip electrophoresis system for online monitoring of atmospheric aerosol composition

Abstract

Atmospheric aerosols are solid or liquid particles that remain suspended in the environment for an extended time because of their size. Due to their high number concentration, low mass concentration, unique size range, and high temporal and spatial variability, atmospheric aerosols represent a significant unknown in both environmental impact and human health. Despite the importance of aerosols, current instrumentation for monitoring their chemical composition is often limited by poor temporal resolution, inadequate detection limits, lack of chemical speciation, and/or high cost. To help address these shortcomings, microchip electrophoresis (MCE) has been introduced for the semi-continuous monitoring of water-soluble aerosol composition. The MCE instrument was coupled to a water condensation particle collector (growth tube), and the integrated system is termed Aerosol Chip Electrophoresis (ACE). ACE is capable of measuring particle composition with temporal resolution of 1 min and detection limits of ~100 ng m-3. This dissertation covers the development process of the prototype ACE instrument, including the novel separation chemistry, necessary modifications to traditional microfluidic devices, and the interface between the growth tube and the microchip.