Skip to main content

Why would a new C18 column show longer retention than an older, used column of the same part number when running an isocratic method? - WKB57068

Article number: 57068


  • C18 columns
  • Column comparison


New C18 columns tend to have more C18 ligand than do older, used C18 columns.



There are many possible reasons why a new C18 column (compared with an old C18 column of the same part number) exhibits longer retention. 

A common cause is that old, used columns have lost C18 ligand as a result of hydrolysis. 

As a column loses ligand, the surface becomes less and less hydrophobic. Installation of a new C18 column of the same part number may show significantly longer retention in some cases (especially if the used column is several years old).

Not able to find a solution? Click here to request help.