A gas chromatographic method and apparatus are provided wherein a reservoir system including at least one reservoir is utilized to collect each component as it elutes from a chromatographic separation column. Immediately after collection of each component, a constant flow of carrier gas is allowed to pass into the reservoir system to carry each component to a detector. According to another aspect of the invention, a method is provided which employs a reference gas mixture in conjunction with the reservoir system to check calibration of a gas chromatography system.