National Institute of Standards & Technology, Acquisition & Assistance Division, Bldg. 301, Rm. B117, Gaithersburg, MD

66 -- AUTOMATED THERMAL-OPTICAL TRANSMITTANCE CARBON ANALYZER SOL 52SBNB6C9189 DUE 072596 POC Debra A. Hoffman 301-975-4648/Pauline E. Mallgrave, Contracting Officer, 301-975-6330 The NIST Atmospheric Chemistry Group is in need of a specially manufactured automated Thermal-Optical Instrument that measures simultaneously the amount of organic carbon, the amount of elemental (soot) carbon, and the amount of inorganic carbonate carbon contained in carbonaceous particles (aerosol) deposited on quartz-fiber (Pallflex type) filters. The measurement process shall be defined by a carefully controlled series of temperature steps to volatilize/ oxidize the particulate carbon on filters with continuous measurement of the following two quantities: (1) the He-Ne laser (diode) light transmittance through the quartz-fiber filter and (2) the amount of methane (CH4) produced from the thermally evolved or combusted carbon oxidized to carbon dioxide (CO2), reduced to methane, and detected by a flame ionization detector (FID). From these two quantities, a measure of the amount of organic carbon, the amount of elemental (soot) carbon, and the amount of inorganic carbonate carbon per unit filter area shall be provided as defined by the method. The instrument shall be similar to the automated Thermal-Optical Instrument reported by Richard L. Johnson, J.J. Shah, Robert A. Cary and James J. Huntzicker in the Americal Chemical Society Symposium Series, No. 167, Atmospheric aerosol: source/air quality relationships, edited by Edward S. Macias and Phillip K. Hopke (1981). (Copies are available upon request.) One major difference in the instrument described here is that it shall measure transmittance instead of reflectance (cf. Johnson et al.). Delivery--FOB Destination, Gaithersburg, MD--shall be six (6) months from the date of the award of the contract. The Government anticipates an award of a firm, fixed price contract. All responsible sources may submit a proposal which shall be considered by the agency. Please request copies of the solicitation (reference the solicitation number) in writing. The fax number is (301) 963-7732. (0156)

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