Don’t Be Alarmed!
The bubbling of gas / liquid that can rarely occur when you remove the end plugs from a brand new Cogent TYPE-C™ column is harmless and does not indicate that the column is damaged.
The escaping gas is a result of the residual solvents and or reagents that were used in the chemical synthesis of the stationary phase and or the column packing process. These solvents or reagents can be trapped in the smaller pores of the silica during the column packing process and escape after time in the column, often after shipping the column.
If you follow the instructions for conditioning the columns, the gas and any residual solvent will be washed away and have no impact on the column life, or your chromatography.
More information on Cogent TYPE-C Silica HPLC columns