The scope of supercritical fluid chromatography continues to enlarge. The use of open tublar and packed columns, nearly universal detectors and the introduction of new mobile phases make it more important. In this work sulfur hexafluoride is evaluated as a mobile phase for supercritical fluid chromatography. The separation of a model aromatic hydrocarbon mixture using different packed columns and operational parameters with UV as a detector is presented. The chromatographic properties of supercritical sulfur hexafluoride and supercritical carbon dioxide are compared under corresponding chromatographic parameters. / Master of Science