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 HLB “Hydrophilic-lipophilic balanced” (HLB) N -vinylpyrrolidone-divinylbenzene copolymer. State-of-the-art spherical polymer for highest demands in solid phase extraction. Advantages: Improved retention for polar substances. High loadability and excellent performance. Water wettable - even if the column bed runs dry, SPE can be continued. Applicable for a wide range of analyte polarities. The hydrophilic-lipophilic balance of the copolymer (spherical part) shows a better retention for polar compounds. SPE at its best!