How to switch off an HPLC system?
ALEXYS, ROXY, DECADE II detector
There are a couple of steps to take to switch off a system for a longer period of time. Shutting down is not different from most other HPLC systems. Switch off the cell and disconnect it from the HPLC system, take some tissues for liquid leaking out and put it on the table (further wash steps below). Put a connector piece in place of the cell and continue with the preparations.
- Avoid precipitation of buffer salts! To avoid bacterial growths, most storage liquids contain high organic content. In such case, first wash out buffer salts with water and low modifier (f.e. 5%), then switch to storage solvent.
Check the column(s) documentation for the appropriate storage liquid, apply this and make sure the column is properly flushed. A reversed phase C18 column is usually stored with 50% acetonitrile /water. Take out the column(s), put end caps on the column to prevent drying out, and store it in an appropriate place. Put a connector piece in place for the following steps.
- For devices other than regular pumps and autosampler, read the manufacturer instructions for appropriate shutdown procedure and solvent compatibility.
Flush and store the system with 50% water/acetonitrile (or methanol). Switch the injector valve between load and inject a few times. Make sure all tubings and the entire flow path is flushed, so no traces of salt are left that could precipitate and clog the system.
Open the cell, flush with demi water, use some tissues to carefully dry the cell. Be careful not to damage the spacer. Close the cell and store dry. In case of salt bridge REF, store the REF separately with a cap on it to prevent drying out. Alternatively, put the sb-REF in a 10 mL closed vial under a KCl solution and close the vial with a cap.