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16.
Water interference in CO2 detection during evolved gas analysis
O.
Peralta, R. Morales, M. Grutter, D. Baumgardner
Centro
de Ciencias de la Atmósfera, UNAM
04510 México, DF, México
The evolved gas analysis, EGA, is a quantitative
method that measures the gases emitted from a sample during its
thermal degradation. In this case the EGA is connected to a multi-pass
absorption cell of a Fourier transform infrared spectrometer (FTIR)
in order to determine the carbon dioxide and water content evolved
from the samples. The CO2 is produced from the pyrolysis reaction
of organic substances in the sample. The largest interference
in the quantification of CO2 is water vapor. Both compounds absorb
radiation in the same waveband, 2.26 ?m. Also water contributes
to the dilution and pressure broadening. In this study, the amount
of water vapor and CO2 produced from the thermal decomposition
of known substances is measured with the FTIR in order to estimate
the water artifact in EGA analysis.
Keywords: EGA, FTIR, CO2 waveband
absorption, H2O interference
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