Material: PP columns with PE filter elements. Further attractive products to complete your chromatography laboratory can be found on our Chromatography page! SPE polypropylene columns ROTI ® X Bond SiOH Unmodified, slightly acidic silica gel Most polar sorbent available to retain polar compounds in a nonpolar matrix Able to seperate compounds with very similar structures Please note: Extremely polar! Adsorbs air humidity. Should be kept well closed and if necessary dried prior to use. Due to its high affinity for polar compounds it should not be conditioned with polar (e.g. methanol) or water containing solvents. Apply analytes in a non-polar solvent, then use a polarity gradient to increase solvent polarity by stepwise addition of polar modifiers such as ethyl acetate or tetrahydrofuran (THF) to complete the separation.