Buffer salts and metals from the HPLC system become imbedded on the surface of the piston seal and gradually wear the surface of the piston rod. Worn regions on the rod will quickly destroy the pump seals. In turn, the seal material gets trapped on the frit at the head of the column, which leads to increased system pressure and/or irregular or poor peak shape. As the piston continues to wear, a leak may develop at the pump.

Any time piston seals are replaced, the piston rod should be inspected with a 10x magnifier or microscope to ensure it does not have wear or scratches. Replace the rod if you observe any glazed regions or scratches.