Abstract: Apparatus is provided for the chromatographic analysis of a plurality of samples having volatile components present in a nonvolatile matrix. The apparatus includes as its principal elements:(a) an oven,(b) A sample cylinder mounted in the oven, which cylinder includes an entry port external of the oven for admitting and withdrawing sample boats from the cylinder,(c) A chromatographic analysis column mounted in the oven,(d) A detector element for analyzing the outlet gas of the analysis column,(e) Two chromatographic trap columns external of the oven,(f) A first gas line for feeding a first carrier gas through the sample cylinder and one of the trap columns,(g) A second gas line mounted in the oven for feeding a second inert carrier gas through one of the trap columns and the analysis column, and(h) A valve assembly having two fixed operating positions which feed the two carrier gases in reversed flow through different trap columns when changed from one operating position to the other.