At Analytics-Shop.com you find a large selection of calibration standards for SEC. Polystyrene (PS), Polymethylmethacrylate (PMMA) and Pullulan are available. PS is well suited for organic solvent SEC (GPC). Less branched polystyrene with anionic polymerization and easily soluble in tetrahydrofuran (THF), chloroform, toluene, and o-dichlorobenzene (ODCB). PMMA is also well-suited for organic solvent SEC (GPC). Narrow molecular weight distribution range and easily soluble in hexaï¬uoroisopropanol (HFIP) and dimethylformamide (DMF). Pullan is recommended for aqueous SEC (GFC). Unbranched pullulan standard and high solubility in water eliminates the possibility of recrystallization.