When working with plasma extracts and Cogent TYPE-C™ columns, we recommend using 50:50 methanol / DI water solvent mixture for washing the column between injections. Flow rates of 0.5ml / minute for 20-30 minutes for a 4.6mm x 250mm column should be sufficient.
When working with LC-MS and biological samples we recommend using 50:50 methanol / DI water as the A solvent. It helps clean the column between runs when biological samples are used. However, for some samples, especially those with a significant amount of lipids, an A solvent of 50:50 DI water / IPA is recommended.