A material containing both volatile and nonvolatile components, such as a compounded high polymer, is analyzed using pyrolysis gas chromatography by directly inserting a sample into a sample injection chamber in contact with a flowing carrier gas stream upstream of a chromatographic column. Prior to inserting the sample, the carrier gas and the sample injection chamber are preheated to a temperature at which the volatile components in the sample will be rapidly vaporized. The temperature to which the injection chamber is preheated is, however, below that which will cause thermal degradation or pyrolysis of the polymeric component of the sample. After substantially all of the vaporizable component is removed from the sample and eluted from the chromatographic column, the polymeric component is pyrolyzed by heating it to a temperature sufficiently high to pyrolyze all of the pyrolyzable components of the sample. The pyrolysates are then carried to the chromatographic column by the carrier gas and eluted from the column. Both the volatile components and the pyrolysates are measured as they are eluted from the column and are graphically recorded to develop a chromatogram and a pyrogram, respectively. The chromatogram represents the specific formulation of the volatile components. The pyrogram represents the chemical structure of the nonvolatile (polymeric) components. Any residue remaining in the injection chamber after pyrolysis can be isolated for subsequent conventional analysis, if desired. Volatile, viscous liquids, such as oils, can also be analyzed by the first step of the procedure outlined above.
