Gas chromatograph calibration of gas mixtures using a versatile precision volumetric apparatus.

A compact, volumetric apparatus was developed for accurate automated preparation of standard gas and gas-liquid mixtures for gas chromatograph detector calibration, with accuracies comparable to those from gravimetric or Coriolis flow methods. The method developed by the principal author is not an adaptation or extension of any other apparatus or technology, and measurements involve only stepper motor steps, temperature, and pressure ratios. Mixture preparation is accomplished via the displacement of gas between chambers in a highly uniform cylinder, separated by a movable piston.