Page 1 of 1
New LC column pressure is too high
Posted: Thu Jun 18, 2020 8:08 pm
by prk018
I've been using a PEEK column (C18, 150mm, ID 4.6mm) on our lab's LC, and I tried switching the old column to a new one - it was exactly the same product with the same specifications. But my backpressure suddenly shot up with the new column - with my old column, with 50ul/min of water flow, I've been maintaining ~100bar. When I switched to the new one, now it's almost at 500bar and I don't understand how just switching the column to a system that has already been working well can dramatically increase the backpressure. Can anyone give me some suggestions?
Re: New LC column pressure is too high
Posted: Thu Jun 18, 2020 11:57 pm
by hplcuserx
Hello, how are you, it could be several things, it has happened to me several times.
As a guide I found this page that served me, I had low pressure actually "Faulty check valve".
It served me, I recommend it!
Meaby
+Problem in pump, injector, in-line filter, or tubing.
+Obstructed guard column or analytical column.
https://whatishplc.com/hplc-troubleshooting/
Re: New LC column pressure is too high
Posted: Fri Jun 19, 2020 5:36 pm
by uzman
What is the particle size of your column , is it sub 2 micron ?
With a flow rate of 50ul/min water flow and 100 bar pressure , it seems like you are using sub 2 micron.
If you are using a high concentration buffer as mobile phase , and connected the new column directly , a buffer precipitation might occurred and a very high pressure observed.
This is because of new columns come with a high concentration of organic solvent inside.
Before connecting the new column directly to a buffered mobile phase , a water rich wash step may be necessary.
Re: New LC column pressure is too high
Posted: Mon Jun 22, 2020 6:14 am
by Gerhard Kratz
You are using a peek column? Maybe the connection is the problem. Do you use a finger tide fitting, do you have stainless steel or peek capillaries? Just cut a little bit of your capillary and connect the capillary fresh with your column. Nothing should be wrong with the column. Don't do body building when you connect a column!
Good luck and stay healthy!
Re: New LC column pressure is too high
Posted: Wed Jul 01, 2020 5:52 am
by Ice9
Column probably stored in ACN, are you sure the pressure difference is just not from pushing the storage ACN off the column, then it will go down to typical levels? I would flush gently with 20 to 50 column volumes and see if the pressure decreases to typical levels as a first step. Solvent fronts can create a lot of back pressure. Especially on small 2.5ยต and smaller particles.