Merck, 54127-U, 2-(2-Pyridyl)ethyl Silica Gel

General description
Retention Mechanism: Anion-exchange
Sample Matrix Compatibility: Organic or aqueous Solutions

Weak anion exchanger ideal for extracting strong basic compounds that remain charged at all pH levels
Unlike conventional weak anion exchange SPE phases such as -NH₂ (aminopropyl) that have a pKa of 9-10, a pH ≤ 7 is required to protonate or ionize the stationary phase to facilitate analyte retention. Elution is typically done by increasing the pH to 11 resulting in neutralization of the SPE phase.
2-(2-pyridyl)-ethyl silica gel has a pKa of ~6. Therefore, analyte elution is feasible at a pH ≥ 7. This characteristic is important for extracting analytes that are not stable (e.g. hydrolyzes) at high pHs typically required for elution when using traditional weak anion exchangers.
Ideal for extracting acyl-coenzyme A esters from tissue.
For more information, please see: Minkler, P.E., Kerner, J., Ingalls, S.T., Hoppel, C.L., Novel isolation procedure for short-, medium-, and long-chain acyl-coenzyme A esters from tissue, Analytical Biochemistry 376 (2008) 275–276