Abstract
A hollow core optical fiber gas sensor has been developed in combination with a Fourier transform infrared (FT-IR) spectrometer operating in the spectral range of 4000-500 cm -1, enabling continuous detection of small volume gas-phase analytes such as CH 4, CO 2, C 2H 5CI, or their mixtures at trace levels. Ag/Ag-halide hollow core optical fibers simultaneously serve as an optical waveguide for broad-band mid-infrared radiation and as a miniaturized absorption gas cell. Specifically, carbon dioxide, methane, and ethyl chloride as well as binary mixtures in a carrier gas were analyzed during exponential dilution experiments. In the studies reported here, the integration of an optical gas sensor with FT-IR spectroscopy provides excellent detection limits for small gas volumes (∼1.5 mL) of individual analytes at a few tens of parts per billion (ppb, vol/vol) for carbon dioxide and a few hundreds of ppb (vol/vol) for methane. Furthermore, the broad-band nature of the radiation source and of the hollow core optical waveguide provides the capability of multi-constituent analysis in mixtures.
Original language | English (US) |
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Pages (from-to) | 331-337 |
Number of pages | 7 |
Journal | Applied Spectroscopy |
Volume | 63 |
Issue number | 3 |
DOIs | |
State | Published - Mar 2009 |
Externally published | Yes |
Keywords
- Carbon dioxide
- Fourier transform infrared spectroscopy
- FT-IR spectroscopy
- Hollow waveguides
- Methane
- Mid-infrared sensors
- Trace gas sensing
ASJC Scopus subject areas
- Spectroscopy
- Instrumentation