Components of an HPLC system Pump All HPLC pumps contain moving parts such as check valves and pistons, and a quite sensitive to dust and particulate matter in the liquid being pumped. Therefo it's advisable to filter the mobile phase using 0.45 or 0.22 um porosity filters prior to use. gassing HPLC eluents, by application of a vacuum and/or ultrasonication or by sparging with helium, also recommended to prevent the problems that can be caused by air bubbles in a pump or detector.