Brownlee Spheri columns are built on small pore (80 Angstrom ) silica in 5 and 10 m particle sizes for analysis of small molecules. These columns are available in three different reverse-phases (C2, C8, C18) and the silica normal phase covers a range of analyte polarities. The Spheri C18 is the most retentive reverse-phase in this family while the C8 is less retentive and can be used for more basic small molecules. Spheri-5 C18 is also available in a monofunctional (comb type) and polyfunctional (ODS) bonding for different analyte selectivities. All Spheri conventional columns are only available in 250 mm length and 4.6 mm i.d.