RPC-03

Endcapping

During manufacture of RP columns, some of the silanol groups remain on the surface of the silica after immobilization of non polar functional groups. This is because of the steric hindrance from C8 or C18 chains. Basically the stationary phase of  RPC should be non polar but the silanol groups are polar. This leads to the chance of interaction of unwanted analytes with stationary phase resulting in poor peak resolution and peak tailing. End capping is used to mask this interaction by replacing silanol groups with trimethylsilyl group.The reagents like trimethylchlorosilane and dichlorodimethylsilane are commonly used for end capping the reverse phase columns.