Mentions: Atmospheric aerosols can negatively affect both theenvironment and health, and therefore aerosol composition needs to be routinelymonitored. Water-soluble inorganic ions are currently monitored using theparticle-into-liquid sampler coupled to ion chromatography (PILS-IC). PILS-ICgives a seven-minute temporal resolution with detection limits near 0.1 micrograms per cubic meter of air for nitrate and sulfate. However, a less expensive,faster, and more portable system is desirable. Here, we describe the coupling ofmicrochip capillary electrophoresis (MCE) to a water-based condensationparticle counter (WCPC) for rapid and continuous monitoring of anions inaerosols. To achieve a working system, several obstacles were overcome. Aworking interface between MCE and the WCPC was developed. A membrane containingsample reservoir was included to filter insoluble aerosols and to inhibitsampling-induced hydrodynamic flow. A flushing system was designed to clean andreplenish the sample reservoir, and the electrophoresis separation chemistrywas optimized to operate continuously for extended times. In-field performanceof the integrated system was tested with atmospheric aerosols. Inorganic anionscan be analyzed in less than a minute with detection limits similar to thePILS-IC, but with improved portability and cost. Continuous monitoring oforganic acids was not previously possible, but it is feasible with WCPC-MCE.Coupling microfluidic devices to aerosol sampling technology proves successfulfor analyzing water-soluble anions, and can be extended to other portions ofaerosols such as cations and carbohydrates. The reduced cost and size relativeto current technology will alllow a greater deployment of monitoring stationsor the development of portable analyzers may be feasible (see Figure 14).
Affiliation: P S Analytical, Arthur House, Crayfields Industrial Estate, Main Road, Orpington, Kent BR5 3Hp, UK.
No MeSH data available.