The Validation of Fourier-Transform Microwave Spectroscopy for Trace-Gas Analysis

Published

February 1, 2002

Author(s)

Pamela M. Chu, R D. Suenram, Angela R. Hight Walker, R S. DaBell, George C. Rhoderick, Gerald T. Fraser

Abstract

There is strong interest by regulatory agencies and automobile manufacturers, motivated in large part by increasingly stringent emission standards, for measurement tools capable of quantifying various hydrocarbons, oxygenated hydrocarbons, etc., in automobile exhausts in near real time with sensitivity comparable to presently used gas chromatographs, i.e. nmol/mol. Concentration measurements of the exhaust-gas composition also potentially provide feedback on the complex chemistry in the engine and exhaust system, which may be used to improve fuel formulations and engine performance and reduce emissions. Here, we describe the technique of Fourier-Transform MicroWave (FTMW) spectroscopy, which is a high sensitivity technique (better than mmol/mol, i.e. 1 ppm) with near real-time response (down to 1 s) and 100 % certain chemical identification. The development of FTMW for gas analysis builds upon a long history at NIST in the quantitative analysis of gas mixtures, which includes standard reference gas mixtures, and more recently the development of a quantitative infrared spectral database of common air pollutants (Chu et al., 1999).

Citation

NIST Interagency/Internal Report (NISTIR) -

Volume

6816

NIST Pub Series

NIST Interagency/Internal Report (NISTIR)

Pub Type

NIST Pubs

Keywords

analytical chemistry, automobile emissions, Fourier-transform microwave spectroscopy, microwave spectroscopy, molecular spectroscopy, trace-gas analysis

Citation

Chu, P. , Suenram, R. , Hight Walker, A. , DaBell, R. , Rhoderick, G. and Fraser, G. (2002), The Validation of Fourier-Transform Microwave Spectroscopy for Trace-Gas Analysis, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD (Accessed October 2, 2025)