The Brownlee Spheri line of columns is based on a small-pore (80 Angstrom ) silica-based sorbent for optimized for separating small molecules. Spheri-5® columns are based on 5 m particle size silica and Spheri-10® incorporates a 10 m silica particle. Spheri-5 columns are available in both reverse phases (RP-8, RP-18, ODS & Phenyl) and polar normal phases (amino, cyano & silica). The Spheri-5 reverse phase C18 type sorbents are available in a monofunctional combtype (RP-18) and a polyfunctional loop-type (ODS) which provide slight differences in selectivity.