Kromasil columns are highpressure slurry-packed with Kromasil spherical silica, 100 Å and 60 Å pore size. Kromasil is a high purity silica with a unique surface chemistry, giving high protein recovery and symmetrical peaks for basic compounds. Kromasil is mechanically stable up to 10000 psi, making it possible to slurry-pack at very high pressures, giving extremely stable column beds. The chemical stability is in the pH range of 1.5 to 9.5 for derivatized Kromasil. Kromasil has a high specific surface area, 320 m2/g for 100 Å and 550 m2/g for 60 Å, giving a high loadability for preparative work.