HPLC Tips - What to do if HPLC runs dry

Here’s a question that came in anonymously because they let their HPLC run dry and they are wondering what to do.
So what do you do if your HPLC runs dry?
First statement: Don’t let it run dry. Here’s a tick: you can set a minimum pressure on your HPLC pump. You basically tell it to shut down when the pressure drops to a specified level. So for example, if you normally run at 100 bar all the time and the pressure drops to 5 bar, then the pump will shut down.
Basically what that means is if it starts pumping air the system will shut down.
So that is one piece of advice to not let air bubbles get into your system.
So let’s deal with the fact that it has already happened.
Here’s my first statement: Don’t freak out! Don’t worry about it, it is not as nearly as bad as you think. People are out there saying, “Air in your column! Your column is destroyed! You just threw away a $500 column.”
NONSENSE! Your column is fine; the instrument is fine.
Now, I don’t want you to run your instrument for long periods of time when it is dry, because your piston will rub against the pump seal, and that will eventually wear out. But that is a long term issue.
But in the short term simply worry about getting liquid back into your instrument.
I would start with 100% acetonitrile or 100% methanol and pump all the air out of the lines. So, open the purge valve to remove all of the air bubbles. At that point you can switch to liquid and start pumping liquid through.
Once you pressurize the column the gasses will dissolve so they will disappear. You will see bubbles coming out for a little while. But once you hydrate that column again, the column is going to be fine.
I know that people say that if a column dries out that the column is ruined. I don’t believe that is true, in fact I have data to say that that is not true.
We actually lost a column under a GC for three years. We found it three years later and put it back on; it pumped bubbles for a couple minutes and from that point on it was perfectly fine.
My theory is that we don’t damage columns when they dry out. It’s an old fashioned worry from the days we were using irregular packing material. We don’t use that anymore, we use spherical. I don’t believe that columns crack when they dry out, that is what used to happen in the olden days.
So what should you do if your HPLC column dries out? Don’t worry about it (don’t tell anyone either!). Put liquid through it and then run a standard to make sure the numbers look good.
My experience is that in most columns you will not have any issues.
Now let me give you a little caveat to that:
For most columns running dry, especially for a short period of time. That includes reverse phase columns, normal phase columns, silica columns; it is a non-issue. You can’t hurt them, you can't damage them, you can’t overpressurize them. They are all fine.
The non-silica based columns we do worry about. So if you are doing size exclusion chromatography, gel filtration chromatography (especially). If you dry out these columns… yeah it is time to buy a new column.
These are very fragile columns. Size exclusion in the gel permeation world as well are very fragile columns. You do not want those to dry out. For ion chromatography I would get nervous if the column dried out. But I wouldn’t freak out.
So other than these exceptions most columns out there won’t be damaged if they dry out. Now, don’t make a practice of it!

[@TheJoshtheboss]

Personally I think dry system is a problem. Regardless of column.
As salts will begin to precipitate around cavities, mixers, pistons, etc. HPLC likes to always have liquid in.

[@AlphaNumeric123]

Excellent video. Extremely useful and way more grounded in the real world. We are taught so much about theory (eg, a dry column will cause cracks) so it’s really nice to hear someone with experience give insights. Btw, this has been my experience as well-a dry column is easily and quickly reconstituted by flowing eluent, no big deal at all. Thank you!

[@shahidabanu6222]

How to fix lost prime alert

[@bezerker2023]

Good lectures bit expensive