Date: 24-APRIL-2013   Last Updated: 22-DECEMBER-2025

Column cleaning is typically performed to remove contaminants that accumulate on the stationary phase or frits during use. If you are injecting clean samples such as standards, cleaning is rarely necessary. However, complex matrices—such as biological or physiological samples—can lead to more frequent buildup.

Cleaning Guidelines

• For complex samples, a good rule of thumb is to wash the column with 50:50 methanol/DI water every 10 injections, followed by re-equilibration with your starting mobile phase.
• Indicators that cleaning is needed include changes in retention time repeatability from run to run.

Preventive Measures

• Use guard columns to protect the analytical column from chemical contaminants that will be adsorbed onto the column.
• For Aqueous Normal Phase (ANP) methods, include 50% methanol or isopropanol in mobile phase A to help reduce contamination.
• Importantly, use a Cogent Column Filter to prevent large, undissolved particles from reaching the column. Every Cogent HPLC column is supplied with a free Cogent Column Filter.

These filters are an economical and effective way to extend column life and maintain performance.