Protect your HPLC columns while in use | Keep systems in service longer.
Guard columns are a very good way to protect your columns while in use. Guard columns should always match your analytical or prep column's stationary phase since the matching phases will make your column a few millimeters longer but will not change the selectivity. If you choose a different phase, you may be trapping some of your analytes. This technique is well known but not considered column protection.
Guard columns will adsorb many chemical entities as well as undissolved particles prior to reaching your column. These particles may permanently adsorb to the analytical column changing its character and selectivity. When the guard column is no longer functioning, showing changes to your peak shape or retention time, it’s time to replace it.
The holders for the Cogent guard systems are listed on this page and the actual guard cartridges are listed with their respective stationary phases.