Detection of carbon monoxide (CO) in combustion gases by tunable diode laser spectrometry is often hampered by spectral interferences from ${\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{CO}}_2$ . A methodology for assessment of CO in hot, humid media using telecommunication distributed feedback lasers is presented. By addressing the R14 line at $6395.4{\mathrm{cm}}^{-1}$ , and by using a dual-species-fitting technique that incorporates the fitting of both a previously measured water background reference spectrum and a $2f$ -wavelength modulation lineshape function, percent-level concentrations of CO can be detected in media with tens of percent of water ( $c_{{\mathrm{H}}_2\mathrm{O}}\le 40\%$ ) at $T\le 1000°\mathrm{C}$ with an accuracy of a few percent by the use of a single reference water spectrum for background correction.