Abstract: Method and apparatus for detecting the presence and proportional amounts of constituents in an unknown gaseous sample. A carrier gas urges the sample through a column containing an adsorption material, which passes known constituents of the gas sample therethrough at predetermined time intervals. The carrier gas and separated constituents are passed over separate temperature sensitive elements to derive a signal representative of the proportion of the constituent being separated at any given time interval. A recorder plots a curve of percentage of concentration constituent versus time, wherein the peaks of the curve represent the particular constituents of the sample.Utilizing air as the carrier, the percentage of nitrogen (N.sub.2) and oxygen (O.sub.2) may be determined through the use of a percentage N.sub.2 - O.sub.2 curve. Means are also provided for determining the temperature of the sample.