Chromatography Forum

Hi all, I am new to this forum. See if you can help me.
In our company we work daily with a gas chromatograph Agilent GC / MS / MS and most of our samples are environmental matrix (sediment, sludge, water and industrial waste). I don't know if caused by matrix tipology or caused by a poor cleanup, the degradation of the column is very fast.

Routinely:
- we change the guard column (1meter aprox),
- we clean the injector
- we change the liner.

And quite often we have:
- we cut the front and back column.
- we perform a column bakeout.

And that's the question: Solvent rinse the column is effective?, Does it work?, is it better than the bakeout of the column?

Thank you very much to everybody
Manel vidal.

I wish there was a definite answer to your good questions.

Contamination of the column MIGHT be removed by thermal heating of the column, but it is just as likely to chemically react with the phase, damaging it.

Rinsing the column MIGHT remove contaminants but it is just as likely to remove damaged phase from the column creating bare, active sites on the column surface.

Generally, removing a length of column from the front (head) of the column is a good practice which will remove contaminants from the column (assuming they have not migrated down the length of the column), but sometimes it is not.

A rinse is the LAST thing you should attempt to restore a column.

Sometimes it works. Sometimes it is the complete destruction of the column.

Clean your samples as much as possible for longer column lifetimes. It is the cost of doing business.

best wishes,

Rod

I wish there was a definite answer to your good questions.

Contamination of the column MIGHT be removed by thermal heating of the column, but it is just as likely to chemically react with the phase, damaging it.

Rinsing the column MIGHT remove contaminants but it is just as likely to remove damaged phase from the column creating bare, active sites on the column surface.

Generally, removing a length of column from the front (head) of the column is a good practice which will remove contaminants from the column (assuming they have not migrated down the length of the column), but sometimes it is not.

A rinse is the LAST thing you should attempt to restore a column.

Sometimes it works. Sometimes it is the complete destruction of the column.

Clean your samples as much as possible for longer column lifetimes. It is the cost of doing business.

best wishes,

Rod

Thank you very much cromatographer, I will follow your advices.

Manel.

Hi Manel,

Can I ask what the symptoms you are finding that tell you your column is degrading?

Is it changes in retention time of known compounds? Clogging? Pressure/Flow changes? Or is it perhaps messy mass spectrums?

The reason I ask is in my experience, over time of running messy samples MS detectors can give poor matching mass spectrums. I called about this and it was suggested to raise the ionization temperature from 200oC to 250oC, and to clean the ionization chamber parts (ceramics, lens, etc.) more frequently. When I did clean it I noticed a brownish tinge to the metal parts in the ionization chamber which was removed when I cleaned with aluminum oxide mixed in glycerol with a cotton Q-Tip. (MS was a quadrapole)