Bio-Beads S-X media are neutral, porous styrene divinylbenzene beads for size exclusion chromatography of lipophilic polymers and other solutes that require organic eluents. Molecular weight exclusion limits range from 400 to 14,000. This range is useful for fractionation of low molecular weight organic polymers and other hydrophobic substances, such as pesticides, rodenticides, polycyclic aromatic compounds, and unsaturated lipids. Exclusion limits are influenced by the eluent used. Separations using Bio-Beads S-X media require an eluent that is mobile; therefore, the beads must be used in a column. Highest exclusion limits are achieved with solvents of greater aromaticity. The beads are compatible with benzene, toluene, xylene, carbon tetrachloride, dimethylformamide, ketones, aromatics, methylene chloride, o-dichlorobenzene, perchloroethylene, tetrahydrofuran, and trichlorobenzene.
Recommended flow rates depend upon the crosslinkage:
- 1% crosslinked resins are used only with gravity flow
- 3% crosslinked resin can withstand a flow of 5 ml/min with a backpressure of 20 bar or 300 psi
- 8% and 12% crosslinked resins can withstand up to 33 bar or 500 psi