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:
- Switch the START/STOP toggle switch to STOP.
- 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-80 PUMP SHOULD BE FILTERED THROUGH 0.2 µm MEMBRANE FILTERS. USE ONLY LC-GRADE SOLVENTS AND TYPE I WATER.
- Place a 50-mL syringe on the prime/purge valve. Check to make sure that system pressure is below 30 PSI, then open the valve one turn. Set the FLOW RATE to 5 mL/min.
- Switch the START/STOP toggle switch to the START position and pump for 5 minutes at 5 mL/min. This will bring fresh solvent through the pump and pulse damper.
If the column is to be cleaned with this solvent, proceed to step 5. If the column has been removed, go to step 6.
- (To clean both the column and the pump.) Set the flow rate to 1 mL/min or other appropriate range. Close the prime/purge valve. Pump 100 mL solvent through the column. Shut the system off, remove and cap the column for storage, and you're done.
- (To clean only the pump.) Remove the column. Set the FLOWRATE to 2 mL/min. Pump 100 mL solvent through the pump, pulse damper, and injector (in INJECT position to flush the loop). Then shut the system off.