METROSEP A Supp 5 150/4.0 Pressure problems

[Fdragon]

Has any one else run into an issue with these columns? We're on our 3rd one and we've gotten about a weeks worth of use out of it.
Our issue is that when we get these guys in they run great at first they stablize in at around 8MPa which is what the Metrohm tech support guys assure me should be the norm. We'll calibrate and run for a day or so and all of a sudden the pressure creeps up and eventally hits 15MPa and shuts down our pump. I dont understand what the problem is 3 columns 2 from the same lot and this new one is from a different lot but it seems like theres a clog in the comuns and we cant get them to operate at the proper flow rate.

[James_Ball]

Has any one else run into an issue with these columns? We're on our 3rd one and we've gotten about a weeks worth of use out of it.
Our issue is that when we get these guys in they run great at first they stablize in at around 8MPa which is what the Metrohm tech support guys assure me should be the norm. We'll calibrate and run for a day or so and all of a sudden the pressure creeps up and eventally hits 15MPa and shuts down our pump. I dont understand what the problem is 3 columns 2 from the same lot and this new one is from a different lot but it seems like theres a clog in the comuns and we cant get them to operate at the proper flow rate.

We have never had a problem with them going out that quickly, ours usually will last for 3 months or even longer, and we run about 70 samples every night.

What mobile phase are you using?
Do you use a guard column?
Do you use the 0.1um filter disk on the autosampler?

[Fdragon]

We're using the standard 3.2mM 2.0mM Sodium Bicarb/carbonate mixture suggested by Metrohm.
Yes we're using a RP2 guard column
We're using the 0.1um filter disk system as well.

[Markus Laeubli, Metrohm]

Did you check where the pressure increase happens? is it on the column itself or one the filter or guard respectively?
What samples do you inject, are they microfiltered?

[Fdragon]

Its specifically on the column if I bypass everything but the column on the system the pressure will imediately build to over 15MPa.
Metrohm tech support had us attempt to rinse the system with acetone and water to remove any organic matrix but alas it did not lower the pressure within the column.

[Markus Laeubli, Metrohm]

What is the matrix and thesource of your samples?

[James_Ball]

If you are injecting any type of organic solvents could it possibly swell the polymer of the column?

If injecting water samples, this does sound odd for it to happen. Unless they are something like sea water.

[Markus Laeubli, Metrohm]

If you are injecting any type of organic solvents could it possibly swell the polymer of the column?

The column is solvent conpatible. Therefore this should not be the reason. Of course mixtures of water and organic solvent my show higher viscosity. But returning to fully aqueous will re-establish normal pressure situation.
Organics immiscible with water will make problems.

[Fdragon]

We're trying to only put samples with good history behind them and were historically clean. I know we also run frakking samples but I dont beleive that we've loaded any onto the instrument after being advised to be careful to not run anything that might have any potential high concentrations of iron

[Markus Laeubli, Metrohm]

High load of iron could be a reason for pressure increase.
Using the Metrosep RP 2 Guard/3.5 (6.1011.030) will keep most of the iron. in this guard the material may be easily replaced (6.1011.130 RP 2 Guard 2 replacement filters).
This prolongs the lifetime of the analytical column.

[smg52]

After the column starts giving high back pressure do you start to see a shoulder on analyte peaks?