Superselective aqueous inorganic phases in vapor-phase gas chromatography

Chromatographic characteristcs of aqueous solutions of inorganic electrolytes, a new class of stationary liquid phases (SLP) for vapor-phase chromatography, are considered. The SLP are characterized by an unusually high selectivity to organic compounds of the R-X type (R is a hydrocarbon radical, X is a polar group,e.g., hydroxyl, carboxyl, and amine; for instance, light C1-C6 alcohols are eluted from the column with a water-containing phase in the following order: hexanol<pentanol<butanol<propanol<ethanol<methanol). The nature of the electrolyte used and its concentration in the water-containing SLP have a crucial influence on the column selectivity and the degree of separation of the compounds subjected to chromatography. This feature provides the possibility of controlling the column selectivity by changing the content of water vapor in the mobile phase.