Chromatography Forum

It is an IC column for the seperation of anions that was used with Sodium Carbonate mobile phase. The frit has become quite dirty and the back pressure has gradually risen too high. So before replacing it I'd like to clean it.

I've heard that backflushing the column with the mobile phase is worth a try. But I am not so sure if it's a good idea. It's a pretty expensive column to risk it.

I have an ultrasonic cleaner available to use if necessary.

The blockage might have been partially caused by accumulation of bacteria and organic matter.

Backflushing is the best (safest) approach because it is non-intrusive. If you remove the end fitting to get at the frit, you risk disturbing the packing bed. In my experience, this is especially true of resin-based materials, which tend to compress a bit under pressure. My recommendation is to change the frit only if backflushing doesn't clear up the problem.

That said, always check with the column vendor/manufacturer to confirm that the column can be back-flushed (some columns, especially the very small particle-size use a wider-pore frit at the inlet than at the outlet).

In my hands concentrated H2SO4 did the best job, by far, of cleaning out organics from metal frits (2x, the second one being sort of a washing step so that succeeding H2O does not precipitate organics). Some metal frits have plastic sections which may not withstand con H2SO4.

Good luck on your cleaning and/or replacement of the frit.

I started using a Krud Katcher on all my analyses and I'm sure I have saved many columns. It is basically just a frit inside of a fitting that you install on the front of the column. It looks like a PEEK fitting. Every once in a while I will find my pressure getting high; I replace the Krud Katcher and my pressures are back to normal.

Ron J.

So far I have replaced the frits, backflushed according to the manual (for organic contam.) sulfuric acid:acetontrile for an hour, then water for an hour.

Normally the pressure of both guard and column should be approx. 1700 and I have about 2300.

What could be causing the extra pressure? Any suggestion for its further reduction?

Unfortunately, columns *do* die. At some point, you have to cut your losses. This may be that point. Remember "Columns are cheap. Your time is valuable."

Are you sure it is the column and not a restriction at some other point in the system? Replace the column with a union and test the pressure should be 0 or very close.

how old is this column? when was the last time it was packed. Contact the mfg and make sure a replacement part is available esp. if its old.

I've had IC columns go from normal operating pressure to over max (gone bad) in the same day. As Tom said, sometimes columns just go bad. If you've spent 2 days or more troubleshooting a bad column then your employer has already paid for a replacement column in troubleshooting time.

On the other hand; if you try a new column and you still have pressure issues then you know your "plug" is occurring somewhere else. If this is the case try Bintang's suggestion or do this anyway if you have to wait for a new column to be ordered.

Ty