When a system is constantly run in Reversed-Phase (RP) HPLC, many unseen contaminants are “retained” on the instrument and can coat the pump seals, frits (screens), check valves and many other parts of an HPLC System. When these contaminants build up, it is time to eliminate them during a PM (Preventative Maintenance) and washed out of the system.

It is important to note that when a system is used for RP HPLC then abruptly is used in Aqueous Normal Phase ANP or HILIC, the change in solvent composition and perhaps the presence of acids or bases could dissolve and force unseen contaminants to “elute” off the system and into the Column or past the detector.

Depending on what these contaminants are (can be sample, impurities, unknowns, dust etc.), they could cause damage to the Column frits, the stationary phase and ultimately, you may see peaks or problems with your data, that may seem very puzzling.