DENSE-GAS CHROMATOGRAPHY OF NONVOLATILE SUBSTANCES OF HIGH MOLECULAR WEIGHT

Working at pressures of up to 2000 atmospheres, more than ten times higher than in previous gas chromatography, we used the solvent power of dense gases to enable migration of chromatographic substances of molecular weights as high as 400,000. Carotenoids, cortical steroids, sterols, nucleosides, amino acids, carbohydrates, and several polymers have been caused to migrate, separated, and detected in NH3 and CO2 carrier gases at temperatures of 140° and 40° C, just above the respective critical points. Previously such compounds either defied separation by gas chromatography or had to be chromatographed as their more volatile derivatives.