Abstract: A pyrolysis/desorption apparatus for use with chromatographic and spectroscopic detection systems for providing chemical analysis of samples. The device includes a tubular body having an interior reaction chamber which houses a pyrolysis/desorption probe adapted for bearing a coating of the sample composition to be analyzed. A separating tube is positioned within the reaction chamber, at a slightly displaced distance from the probe for receiving reaction product entrained within a carrier gas. A carrier gas inlet is coupled to the tubular body upstream from a portion of the reaction chamber and operates to introduce carrier gas flow through the reaction chamber and toward an opposing end of the tubular body. A carrier gas outlet is located down stream from the reaction chamber for venting carrier gas and entrained reaction products which are not split off by the separating tube.