The Ascentis family of columns is the fourth generation of HPLC column technology from Supelco scientists. Ascentis columns are bonded on high purity, 100 Angstrom silica including 3, 5, and 10 micron particle size. Columns are designed for small molecule applications and are scalable from micro columns (1.0 mm I.D.) to preparative dimensions (50 mm I.D.). The family includes C18, C8, Phenyl, Si and embedded polar group phase, RP-Amide. Ascentis C18 is an extremely stable and reliable first choice HPLC column that gives symmetric peak shape and excellent retention even for difficult compounds.. Excellent retention. Symmetric peak shape. High reproducibility. Complete LC-MS compatibility. . Sigma-Aldrich 581324-U Ascentis C18 HPLC Column, 5 µm Particle Size, 4.6mm ID, 15cm Length. Country of Origin : United States. Part Number : 1191X74EA. Pack of : 1.