Demonstration of High Speeds with Low Pressure Drops Using 1.8 μm Particles in SFC

Abstract

The literature contains few, if any, references to the use of sub-2 μm particles in supercritical fluid chromatography (SFC). In this study, the use of 1.8 μm particles in SFC is demonstrated, producing high efficiency chromatograms, less than 1 min long for each of a diverse range of solute families, including steroids, sulfonamides, profens, nucleic acids and xanthenes. Most of the solutes eluted from bare silica with surprisingly good peak shapes. The 3 × 100 mm column packed with 1.8 μm spherical silica particles, produced as many as 22,400 plates (80% of theoretical). Column head pressure did not exceed 410 bar and pressure drops did not exceed 240 bar, even at flows of 3 mL min−1, or modifier concentration as high as 65%. Such performance produced the fastest solvation based chromatography (LC–SFC) reported to date. The chromatographic hardware requirements are met by older (400 bar max.) LC equipment. The speeds observed exceed even ultra high performance liquid chromatography (UHPLC), which requires dramatically higher pressure capability. Sub 2-μm particles appear suitable for routine use, employing common 400 bar LC equipment, only slightly modified to perform SFC, although faster detectors and smaller flow cells enhance performance.