Applications of Packed-Column SFC Using Light-Scattering Detection

Abstract

The application of packed-column supercritical fluid chromatography using ultraviolet and evaporative light-scattering detection in series for the analysis of a range of polar, nonchromophoric analytes is reported. Cyano-, amino-, silica, and -cyclodextrin columns were used with carbon dioxide-methanol, carbon dioxide-methoxyethanol, or chlorodifluoromethanemethanol mobile phases. The performance of the system is dependent on the geometry of the nebulizer spray device in addition to the temperature and pressure (density) of the mobile phase and the percentage of solvent entrainer used. However, this may be optimized by adjustment of the nebulizer gas pressure and drift tube temperature of the detector. The technique offers a means of separating and detecting a wide range of organic compounds not normally directly amenable to high-performance liquid chromatography or supercritical fluid chromatographic analysis using ultraviolet detection and provides a rapid means of confirming optimum component separation and the purity of samples. The applicability of the technique is illustrated by analysis of mixtures of steroids, underivatized amino acids, underivatized carbohydrates, and ionophores, by the separation of plant pigments within a leaf extract, and by the confirmation of the purity of a peptide standard.