Ultisil Diol Column is based on ultra-pure porous spherical silica bonded with 1,2-dihydroxypropyl functional group silica. Ultisil Diol is used in normal phase mostly, suitable for separation of peptides, proteins, polar molecules, and organic acids and its polymers. Like bare silica, Ultisil Diol has the ability to form hydrogen bonds and is capable of separating structural isomers. Since most of its surface is covered with organic functions, Ultisil Diol absorbs less water, which leads to more reproducible activity. It is also the sorbent of choice when working in normal phase in the presence of water. It has a different selectivity than bare silica gel, and slight modification in the composition of solvent mixture may be necessary to obtain a similar retention. Ultisil Diol column is more stable than traditional normal phase columns, such as NH2, SiO2. Compared with NH2/SiO2 column, Diol column is not sensitive to water. Ultisil Diol column can also be used in reversed phase analysis.