SUPELCOSIL LC-DB phases are specially deactivated for basic compounds. These columns provide shorter retention, better peak shape, and higher efficiency for organic bases than can be obtained on other Type A silica reversed-phase columns.. Application(s): HPLC: suitable. Matrix: Silica gel, spherical particle platform. L × I.D. 25 cm × 4.6 mm. . . Sigma-Aldrich 58355-U SUPELCOSIL LC-18-DB HPLC Column, 5 µm Particle Size, 4.6mm ID, 25cm Length. Country of Origin : United States. Part Number : 1193U65EA. Pack of : 1.