In many cases, you will not need ion-pair agents when using Cogent TYPE-C Silica™ columns. Ion pair agents are generally used to either increase retention of a poorly retained compound in reversed phase (RP) or to improve peak shape due to silanolic tailing.

The Cogent TYPE-C™ Silica columns can retain analytes by aqueous normal phase (ANP) which is highly suited to retention of polar compounds already without ion-pair agents. Furthermore, these columns have very few surface silanols due to the silica hydride surface and therefore tailing due to these moieties is much less problematic.

It has been demonstrated that ANP can analyze positively or negatively charged compounds having molecular weights below 100 to larger molecules such as peptides. Polar uncharged molecules can also be analyzed by this approach. In every case the mobile phases do not contain more than 10 mM of an additive such as acetic or formic acids, or ammonium acetate or formate, all of which are MS compatible.

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