University of Illinois Urbana-Champaign

Headspace Analysis Of Volatile Compounds Using Segemented Chirped-pulse Fourier Transform Mm-wave Spectroscopy

Pate, Brooks

Content Files
MJ01_Abstract.pdf
MJ01_Abstract.txt
MJ01_Presentation.pptx

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https://hdl.handle.net/2142/51175

Description

Title
Headspace Analysis Of Volatile Compounds Using Segemented Chirped-pulse Fourier Transform Mm-wave Spectroscopy
Author(s)
Pate, Brooks
Contributor(s)
  • Steber, Amanda
  • Harris, Brent
Issue Date
2014-06-16
Keyword(s)
Analytical, Combustion, Plasma
Date of Ingest
  • 2014-09-17T16:56:22Z
  • 2015-04-14T18:38:05Z
Abstract
A chirped-pulse Fourier transform mm-wave spectrometer has been tested in analytical chemistry applications of headspace analysis of volatile species. A solid-state mm-wave light source (260-290 GHz) provides 30-50 mW of power. This power is sufficient to achieve optimal excitation of individual transitions of molecules with dipole moments larger than about 0.1 D. The chirped-pulse spectrometer has near 100\% measurement duty cycle using a high-speed digitizer (4 GS/s) with signal accumulation in an FPGA. The combination of the ability to perform optimal pulse excitation and near 100\% measurement duty cycle gives a spectrometer that is fully optimized for trace detection. The performance of the instrument is tested using an EPA sample (EPA VOC Mix 6 – Supelco) that contains a set of molecules that are fast eluting on gas chromatographs and, as a result, present analysis challenges to mass spectrometry. The ability to directly analyze the VOC mixture is tested by acquiring the full bandwidth (260-290 GHz) spectrum in a “high dynamic range” measurement mode that minimizes spurious spectrometer responses. The high-resolution of molecular rotational spectroscopy makes it easy to analyze this mixture without the need for chemical separation. The sensitivity of the instrument for individual molecule detection, where a single transition is polarized by the excitation pulse, is also tested. Detection limits in water will be reported. In the case of chloromethane, the detection limit (0.1 microgram/L), matches the sensitivity reported in the EPA measurement protocol (EPA Method 524) for GC/MS.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
English
Permalink
http://hdl.handle.net/2142/51175
DOI
https://doi.org/10.15278/isms.2014.MJ01
Copyright and License Information
Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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Abstracts & Presentations - 2014 International Symposium on Molecular Spectroscopy PRIMARY