Chromatography
One Stationary Phase, Three Modes of Separation: Reversed Phase and Normal Phase Separations on the Same Column
Aug 05 2006
Author: Joseph J. Pesek, Maria T. Matyska on behalf of Unassigned Independent Article
The most commonly used support material for HPLC packings are spherical, micro porous particles of silica and these are amorphous (i.e. non-crystalline) in nature. The surface of the silica particles shows poor homogeneity, being a mixture of silanols (Si-OH) of varying degrees of activity, and siloxane groups (Si-O-Si). This makes subsequent surface modifications to produce bonded phases greatly reliant on the nature of the base silica. Early silicas, made from sodium silica sols, were referred to as type A silicas. The more recent ultra pure silicas (exhibiting much lower levels of transition metal ions and better surface homogeneity - resulting in more reproducible and better chromatographic performance) , made from organic sols, are referred to as type B silicas. In this article Joe Pesek and Maria Matyska discuss a type C silica which is designed to reduce problems associated with types A&B silicas when modified.
Digital Edition
Lab Asia 31.2 April 2024
April 2024
In This Edition Chromatography Articles - Approaches to troubleshooting an SPE method for the analysis of oligonucleotides (pt i) - High-precision liquid flow processes demand full fluidic c...
View all digital editions
Events
Apr 22 2024 Marrakech, Morroco
Making Pharmaceuticals Exhibition & Conference
Apr 23 2024 Coventry, UK
Apr 23 2024 Kintex, South Korea
Apr 23 2024 Seoul, South Korea
Apr 24 2024 Jakarta, Indonesia