Aethalometric Liquid Chromatographic Mass Spectrometric InstrumentEPA Grant Number: R831074
Title: Aethalometric Liquid Chromatographic Mass Spectrometric Instrument
Investigators: Dasgupta, Purnendu K.
Institution: The University of Texas at Arlington
EPA Project Officer: Chung, Serena
Project Period: September 1, 2003 through December 31, 2007 (Extended to December 31, 2008)
Project Amount: $450,000
RFA: Measurement, Modeling, and Analysis Methods for Airborne Carbonaceous Fine Particulate Matter (PM2.5) (2003) RFA Text | Recipients Lists
Research Category: Air , Air Quality and Air Toxics , Particulate Matter
This project will fabricate, evaluate and field-test a new instrument that relies on a pair of alternately sampled filters with aethalometric measurements provided on the filter itself. The filter is to be sequentially extracted with multiple solvents and the extracts will be analyzed on-line by liquid chromatography with sequential photodiode array detection in the UV (Visible) followed by mass spectrometry. The system will be fully automated and be capable of unattended operation with a one sample processed every 30-60 min.
No attempts have yet been made towards automated detailed on-line chemical characterization of atmospheric particulate matter. This project will attempt to do so for the first time.
This work will characterize spherical glassy carbon containing (NH4)2SO4 aerosols and extractable fullerene-containing sub-mm size soot carbon, also contained in (NH4)2SO4 aerosols, as elemental carbon (EC) and EC- OC (organic carbon) standards. Radial pattern of transflectance measurement on the sampling filter will be explored to provide size information on EC measurement. Testing will first be conducted with a system designed to measure carboxylic (especially long chain) acids and wood smoke measurements will be made. Sequential solvent extraction using the fullerene containing soot aerosol and chromatographic separation using different phases of varying polarity will be carried out to choose an instrument configuration that will lead to the extraction and separation of a broad variety of analytes. The instrument will then be field tested in the Advanced Vehicle Engineering Research Laboratory at Texas Tech University on auto exhaust. The instrument will then be field tested, alongside commercial aethalometric and EC/OC instruments and relationships of the data generated by the different instruments will be examined. Depending on the availability of further funding and resources, field studies will be carried out at Houston, TX, and the Baltimore, MD supersite.
The proposed work will address the need of reliable EC/OC calibration standards, examine artifacts from organic vapors and other gases, provide the first systematic attempt at on-line analysis of organics in ambient particulate matter, reduce the time and effort required to analyze complex organic samples, provide facile means to identify new tracers for specific emission sources and allow investigations of regional differences in tracers and sources.