Prepacked ROTI ® Dex-Grav columns for size exclusion chromatography by gravity, for fast and efficient removal of unwanted low molecular weight factors, such as impurities, salts, excipients, markers, cell debris, etc. from protein or nucleic acid solutions. The purification is based on a spherical porous gel filtration medium consisting of dextran cross-linked with epichlorohydrin. In size exclusion chromatography molecules are separated according to their size in solution. Smaller molecules pass through the column much slower than larger molecules. In contrast to other chromatography methods, no interactions occur here between the analyte and the stationary phase of the column. This provides the ideal basis for the purification and analysis of intact proteins. Advantages: Sample preparation in just a few minutes Desalting, removal of impurities and buffer exchange in a single step No interaction between analyte and medium High selectivity, high resolution and high yield (> 95%) Also suitable for small sample volumes High chemical stability and therefore compatible with many organic and other solvents Size Exclusion Chromatography Columns ROTI ® Dex-25 Medium Grav M The column bed consists of ROTI ® Dex-25 Medium (Art. No. 21A5), pre-swollen in deionised water. Suitable for: Oligonucleotides > 10 bp Globular proteins > 5 kDa Particles > 2 nm Column size M is recommended for sample volumes of 1 ml. Detailed information on the application can be found in our Technical Information Brochure and in our Instructions for Use.