Taking advantage of recent developments in the area of microfluidics and microelectromechanical (MEMS) systems, Colorado State University researchers will develop and test a miniaturized, microchip based aerosol analyzer, to be coupled with existing interface systems appropriate to the detection and analysis of size resolved precipitation and aerosols.
Analytical systems using microchip capillary electrophoresis (MCE) with Electrochemical Detection (ECD) are suggested to be versatile systems capable of measuring inorganic anions and cations, carboxylic acids and anhydrocarbohydrates (e.g., plant combustion biomarkers such as levoglucosan, mannosan, galactosan), all of which are of interest in characterizing ambient aerosol sources and composition.
The development of miniaturized, inexpensive aerosol analyzers holds the potential of their operation in dense sampling networks, personal exposure monitors, deployment on small unmanned aircraft systems, and in real time air-quality monitoring and aerosolized agent detection schemes, all of the above having potentially broad and desirable societal goals.
This project developed a microfluidic sensor for measuring the composition of atmospheric aerosols. Atmospheric aerosols represent the most significant unknown in our understanding of the impact of human activity on the Earth’s climate. New tools are needed to measure aerosol composition because the composition dictates the climatic impact of a given particle. Existing tools tend to be large and expensive and thus can only be deployed in a few places at a given time. In this project, we successfully created this new sensor along with the chemistry necessary to quantify small anions in the samples such as nitrate and sulfate. The sensor is capable of measuring concentrations approximately once per minute and costs approximately $20,000 to make. This is compared to the other techniques used to make similar composition measurements that cost between $50,000 and $500,000. Once constructed, the sensor was tested in a variety of settings including laboratory air, outdoor ambient air in two different sites in CO, and air sampled over a 5 week period outside of Sacramento, CA. In all cases, we were able to track changes in analyte concentrations with high temporal resolution and measurement accuracy. This technology will allow us to make more measurements of aerosol composition at more sites and thus fill in missing gaps to our knowledge of aerosol composition variations.
