2.5.2 Cavitation
Cavitation occurs when inlet conditions restrict the flow of solvent and vapor bubbles are formed during the inlet stroke. The key to preventing cavitation is to reduce inlet restrictions. The most common causes of inlet restrictions are crimped inlet lines and plugged inlet filters. Inlet lines with tubing longer than 48" (120 cm) or with tubing of less than 0.085" (2 mm) ID may also cause cavitation.
Placing the solvent reservoirs below the pump level also promotes cavitation. The optimal location of the reservoirs is slightly above the pump level, but it is adequate to have them on the same level as the pump.
2.5.3 Filtration
Solvent filtration is good practice for the reliability of the Binary Solvent Delivery Module and other components in a HPLC system. Solvents should always be filtered with a 0.5 micron filter prior to use. This ensures that no particles will interfere with the reliable operation of the piston seals and check valves. Solvents in which buffers or other salts readily precipitate out will need to be filtered more often. After filtration, the solvents should be stored in a closed,
2.5.4 Initial system pressurization (Daily)
IMPORTANT: To maximize accuracy at all pressures and flows this pump contains a pulse damper for each solvent used. It is important that the pump be brought to pressure with both pumps running to insure that each pulse damper has the correct solvent in it. It is recommended that the flow be set to the operational flow with an equal mixture of the two solvents. Once the system has reached a constant pressure the composition should be set to the initial conditions.
2.6Instrument Installation
2.6.1Mobile Phase Reservoirs
The mobile phase reservoir should be placed at the same level or slightly higher than the pump, never below the pump, and the inlet tubing should be as short as practical. These steps minimize pressure losses on the inlet side of the pump during refill and help to avoid bubble formation. These steps are particularly important when using high vapor pressure solvents (hexane, methylene chloride, etc.). Mobile phases should be degassed, filtered and covered. (See Section 2.4.)
