Leaving the Lab for Time Off Means Recovery Time for You and Your HPLC Instrument

[michael-heidorn]

The holiday season is considered the best time for a family reunion.

During the holidays, detaching from work stress and finding peace are the most important things you can do to recharge. It is time to focus on yourself and your family to spread love, laughter, gratitude, warmth and smiles.

During this time, we come to rest and recharge but should not think about work — especially in large contract laboratories. There might be a vacation schedule and stand-ins to keep business going.

Nevertheless, not all HPLC instruments may be fully utilized during vacation periods. Fewer HPLC analysis orders come in because clients are on vacation, too. There is also a risk that HPLC instruments will run out of solvents if all of them stay in operation, because there are fewer staff members to take care of them.

Whenever possible, the lower number of HPLC applications per day during vacation periods are consolidated and run on a reduced number of HPLC systems to reduce maintenance activities and operation costs. There might be many reasons why some HPLC instruments are switched off during the holidays in almost every lab.

For this holiday season, Saša Kapetanović (manager, product support for HPLC and chromatography consumables) and I want you to take care of your HPLC instrument!

But you need to follow some minimum steps to properly shut down your HPLC instrument. Please, never just turn it off. It would be a pity if you came back from vacation and found your favorite instruments in bad condition. This might ultimately lead to stress and frustration on your first day back at work.

It is the same bad idea as simply turning off a coffee maker after you have finished your last hot cup of coffee and going away for a few days. I am not just talking about the water reservoir that might look like a fishbowl when coming back. You can smell the wet and moldy coffee grounds that you left in the filter or pad.

And let’s face it, everyone forgets to clean and prepare the shutdown of a coffee maker at some point in their lives. When you open the coffee maker after a few days of no usage, you might consider whether it makes more sense to buy a new one instead of intensive cleaning – because you always remember the picture.

I promise the coffee from this coffee maker will never taste the same again. And no, a fully automatic coffee machine does not look better after some days of no usage when it was not prepared for shutdown before.

Grounds for dismay: You forgot to clean out your coffee maker before taking time off?

Similar things can happen to your HPLC instrument if you just ”turn it off.“

• It might not smell, but nature strikes back anyway. Life flourishes in aqueous solvents. Buffer solutions form beautiful crystals.
• Your capillaries can clog, and the flow cell could lose transition.
• The columns could give you a full spectrum of ghost peaks, or no peak, and instead a high baseline noise.
• The column back pressure may exceed the maximum system pressure as soon as the pump is turned on.

I bet you now have your own bad stories and experiences in mind.

For our HPLC Support Center, I wrote some general guidelines about best practices for the following scenarios with standard HPLC instruments:

Short-term (>24 hours to two weeks) shutdown procedure for standard HPLC instruments

1. Prepare the column for storage. Refer to the column’s operating manual for appropriate storage conditions.
2. Remove the columns from the system and plug the inlet and outlet ports to prevent the column material from drying out
3. Connect the LC tubing with an appropriate connector (e.g., Viper union.)
4. Flush the system with a mixture of 10 percent methanol or acetonitrile in 90 percent deionized water mixture for at least 30 minutes at a flow rate of 1 mL/min.
5. Remove all samples from the autosampler racks.
6. Check waste containers and empty if required.
7. Turn off all system components.

Prolonged (two weeks or more) shutdown procedure for standard HPLC instruments

1. Prepare the column for storage. Refer to the column's Operating Manual for the appropriate long-term storage conditions.
2. Remove the columns from the system and plug the inlet and outlet ports to prevent the column material from drying out.
3. Connect the LC tubing with an appropriate connector (e.g., Viper union).
4. Flush the system with a mixture of 10 percent methanol or acetonitrile in 90 percent deionized water mixture for at least 30 minutes at a flow rate of 1 mL/min.
5. At a minimum, remove all reservoirs containing aqueous solvents, preferably all reservoirs containing organic solvents as well.
6. Flush all solvent lines of the system with 100 percent isopropanol or methanol for at least 10 minutes at a flow rate of 1 mL/min.
7. Remove all samples from the autosampler racks.
8. Empty all waste containers
9. Turn off all system components.

Follow the specific shutdown guidelines in the respective operating manuals for some LC components, like charged aerosol detectors and mass spectrometers, and the Thermo Scientific™ Vanquish™ Neo UHPLC Systems.

I also created this article about HPLC column care guides because your HPLC column is the most critical component when talking about consistent HPLC results.

Your data quality will greatly depend on your column handling and storage conditions, so please treat your solid phases well! You can easily extend the lifetime of your HPLC columns by adhering to such recommended guidelines in handling and storage.

We hope you find the shutdown and storage guides useful for getting the same good quality results —as you did before the holidays — and increasing the life of your HPLC instrument and columns.

Saša Kapetanović contributed to this blog post.