Properly shutting down the HTEC will ensure preservation of functionality after a long hiatus (weeks to months). Most issues dealing with improper storage are related to salt precipitates clogging lines when mobile phase dries out, or bacteria growth,
HTEC-500/510 Shutdown Protocol:
1. Please refer to your specific HPLC separation column user manual for the appropriate storage conditions as it may vary between columns. All enzyme immobilized columns (reactors) need to be removed and stored in an appropriate buffer and kept in a refrigerator. Remove column and precolumn from the system and replace it with a two-way joint. Repack the precolumn before the start of the next analysis.
2. Replace mobile phase in the HTEC system with 20-30% methanol in water. Removing salts from the lines will prevent crystallization and methanol will prevent bacterial growth. During this process, switch off the ECD. Run for approximately 1 hour to flush the lines then turn off the pump.
3. Wash the piston using ultrapure water from the pump wash port. Wash the ports of the manual injector using ultrapure water.
5. Unscrew the fixing nut at the reference electrode on the ECD cell and put the reference electrode at 4°C keeping it’s tip in 1 M LiCl/0.1 M CH3COOH in a vial (preferably the one that came with the reference electrode). Remove the working electrode and gasket and store in a dry place. Place a piece of foam in place of the working electrode and close the ECD cell.
6. When the HTEC is ready for long-term storage, the degasser, the pump, the injector and all the tubing are filled with 30% methanol and the ECD will become dry without the reference or working electrodes. Please ensure the power is off.