The most important principle to remember when turning off your pump for storage is to remove all mobile-phase salts. Salts in the system will lead to corrosion of the stainless steel lines (yes, they corrode, but at a slow rate), and the presence of abrasive crystals in the pump heads. Abrasives will scratch the seals and plungers during subsequent startup.
The shutdown procedure is as follows:
- Turn the POWER on.
- Place the solvent-pickup frit in a reagent bottle containing 40:60 (v:v:) acetonitrile:water. Elevating the reservoir to provide hydrostatic pressure will be helpful.
NOTE: ALL SOLVENTS AND MOBILE PHASES USED IN THE PM-90 PUMP SHOULD BE FILTERED
THROUGH 0.2µm MEMBRANE FILTERS. USE ONLY LC-GRADE SOLVENTS AND TYPE I WATER.
- Check to make sure that system pressure is below 30 PSI. Replace the prime/purge plug on the manifold with the luer adapter and connect a 60-mL syringe to the luer adapter.
- Press the PURGE key then press the RUN/STOP key to begin purging the pump. Purge for five minutes. This will bring fresh solvent through the pump.
- If the column is to be cleaned with this solvent, proceed to step 6. If the column has been removed, go to step 7.
- (To clean both the column and the pump.) Set the flow to 100µL/min or other appropriate range. Replace the luer adapter with the plug. Pump an appropriate amount of solvent through the pump, injector (in INJECT position to flush the loop), and column. Shut the system off, remove and cap the column for storage.
- (To clean only the pump.) Remove the column. Set the flow to 1999µL/min. Pump an appropriate amount of solvent through the pump and injector (in INJECT position to flush the loop). Then shut the system off.
- Squirt a few drops of water into the plunger-irrigation ports. Use only enough water to moisten the plungers.