HPLC

Ascentis Silica HPLC Columns

High Surface Area and High Surface Deactivation Combine to Give Ascentis Silica Exceptional Performance as a Normal Phase, HILIC and Preparative HPLC Material

Besides being the underlying support for all Ascentis phases, Ascentis Silica has applications in its own right. Silica is widely used to separate positional isomers in normal phase mode, and polar compounds in HILIC (aqueous normal phase modes). Silica is also used in organic synthesis to purify reaction mixtures. In each case, a high purity, controlled and uniform surface is necessary to impart the desirable chromatographic performance.

Features

  • High-loading capacity
  • Operates in both normal-phase and HILIC modes
  • Tested in both modes and shipped in ethanol, Ascentis Silica is ready to use in either mode
  • Ultra-pure, spherical silica
  • Available in 3, 5, and 10 µm

Key Applications

Small molecular weight positional (geometric) isomers, non-polar compounds (in NP mode), vitamins, steroids, polar compounds (in HILIC mode)

Properties
USP Code: L3
Bonded Phase Description: None (surface comprises silanol, -Si-OH, and siloxane, -Si-O-Si-, groups)
Endcapped: No
Particle composition: Type B silica gel
Particle Purity: <5 ppm metals
Particle Shape: Spherical
Particle Size: 3, 5 and 10 µm
Pore Size: 100 Å
Surface Area: 450 m2/g
Carbon Load: 0 %
pH Range (recommended): 2 to 6

Ordering Information for Ascentis Silica HPLC columns

Use

  • Normal phase and HILIC HPLC modes
  • Preparative chromatography
  • Purification (organic synthesis)
  • LC-MS

The classic use of silica columns is for normal phase HPLC. The rigid structure of the silica surface, as opposed to the flexible nature of bonded phases, allows it to distinguish between molecules with different footprints that may have the same hydrophobicity. Geometric isomers and closely-related substances, like the steroids shown in Figure 15, can be separated on Ascentis Silica under normal phase conditions. Normal phase is also widely used in preparative chromatography because the mobile phase is more easily removed by evaporation than the water-containing reversed-phase mobile phases.