USE OF CYLINDER MIXTURES OF VOLATILE AND NON - VOLAT.I LE HYDROCARBONS FOR CALIBRATION OF PROCESS ANALYZERS

摘要

Chromatographs that inject sample in the liquid phase can be subject to calibration errors due to compositional changes in the calibration blends as the sample is consumed. These errors are due to the differences in solubilities and vapor pressures of various components in the sample. The magnitude of the errors is especially significant for blends that contain the lighter hydrocarbons. A series of mixtures of volatile and high-boiling hydrocarbon mixtures have been analyzed to determine the change in composition as the sample is consumed. Changes in composition can be predicted and corrections made to minimize errors. Techniques for correcting for and minimizing errors due to compositional changes are described.