A Compact, In-Situ Instrument for Organic Acids

76023-Among the contributors to atmospheric pollution, carboxylic acids (including mono- and dicarboxylic acids, aliphatic ketoacids, and aromatic acids) are an important class of oxygenated, organic compounds in atmospheric aerosols. To better understand their sources and atmospheric transformation processes, an automated method for measuring their concentration is required. This project will develop a new, in-situ instrument for the routine identification and quantification of organic acids in the particulate phase. The system will combine an innovative method for particle concentration and collection with emerging ¿laboratory on a chip¿ capillary electrophoresis analytical methods. The analytical microchip, measuring a few centimeters across, will contain all of the critical components for chemical quantification, including the collection reservoir, capillary electrophoresis separation column, and conductivity detector. Phase I will: (1) adapt a water condensation technology for the direct deposition of submicrometer and nanometer diameter particles onto the analysis chip, (2) evaluate the capillary electrophoresis microchip analysis of directly deposited standards at the sub-nanogram level, and (3) interface these technologies to demonstrate the potential of the method using laboratory-generated aerosols. Commercial Applications and Other Benefits as described by the awardee: The instrument should find use in the routine, hourly monitoring of carboxcylic acids in atmospheric aerosols, substantially lowering the cost per sample and providing higher time resolution than possible with current methods.