HR: 1340h
AN: A33B-1192    [Abstracts]
TI: Continuous Monitoring of Nitrate and Sulfate in Aerosols with Microchip Electrophoresis
AU: * Noblitt, S D
EM: noblitts@lamar.colostate.edu
AF: Colorado State University, Chemistry Department, Fort Collins, CO 80523,
AU: Henry, C S
EM: cshenry@lamar.colostate.edu
AF: Colorado State University, Chemistry Department, Fort Collins, CO 80523,
AU: Collett, J L
EM: collett@atmos.colostate.edu
AF: Colorado State University, Atmospheric Sciences Department, Fort Collins, CO 80523,
AU: Hering, S V
EM: susanne@aerosol.us
AF: Aerosol Dynamics Inc., 935 Grayson St., Berkeley, CA 94710,
AB: Routine monitoring of aerosol composition is important since aerosols can negatively affect both the environment and health. Water-soluble inorganic ions are commonly monitored using the particle-into-liquid-sampler coupled to ion chromatography (PILS-IC). However, a less-expensive, faster, and more portable analysis system is desirable. Here, we present the coupling of microchip capillary electrophoresis (MCE) to a water-based condensation particle counter (WCPC) for rapid and continuous monitoring of chloride, nitrate, and sulfate in atmospheric aerosols. To achieve a working system, several obstacles were overcome. A working interface between the electrophoresis microchip and the WCPC sampler was developed. This interface was designed to remove insoluble particles from the analysis stream and to prevent the sampling-induced pressure gradient from altering flow in the microfluidic device. The electrophoresis separation chemistry was optimized for the small chip size, to be free from potential interfering compounds, and to operate continuously for several hours. In-field performance of the integrated system was tested with ambient aerosols. Anion analyses can be performed in less than two minutes with aerosol detection limits similar to the PILS-IC, but with greater portability and reduced cost. Coupling microfluidic devices to aerosol sampling technology proves successful for inorganic anion analysis and shows potential for faster and more sensitive measurements as well as monitoring of other water- soluble aerosol components such as organic acids, cations, and carbohydrates. The reduced cost and size relative to current technology indicate that greater deployment of monitoring stations or the advent of portable analyzers may be feasible.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting