Pump:
•The role of the pumpis to force a liquid (called the mobile phase) through the liquidchromatograph at a specific flow rate, expressed in milliliters per min (mL/min).
•Normal flow rates in HPLC are in the 1-to 2-mL/min range.
•Typical pumps can reach pressures in the range of 6000-9000 psi (400-to 600-bar).
•During the chromatographic experiment, a pump can deliver a constant mobile phase composition (isocratic) or an increasing mobile phase composition (gradient).