CHLOROFLUOROCARBONS ALTERNATIVES ANALYSIS .1. THE DETERMINATION OF HFC-134A PURITY BY GAS-CHROMATOGRAPHY

Characterization and determination of the impurities present in 1, 1, 1, 2-tetrafluoroethane (HFC-134a) is critically important to the authenticity of toxicological test results and to the evaluation of HFC-134a as a suitable refrigerant for replacement of primarily Freon 12. Following impurity identification by molecular spectroscopic techniques, two gas chromatographic methods, one capillary and the other a combination packed column with flame ionization detection (FID), have been developed and are used to monitor the purity of HFC-134a samples prepared from various starting materials primarily for use in the Program for Alternative Fluorocarbon Toxicity Testing (PAFTT)-related toxicity studies. A sampling and calibration technique has been implemented and found suitable for a gaseous product containing volatile impurities with a comparatively wide range of boiling points. Carbon number substituent effects were estimated and are used to determine the amounts of impurities present for which pure compounds are not available. © Oxford University Press 1992.