Chromatography Forum

Hello everyone,

I am writing to ask if there was an average lifetime of columns used in gas chromatography?

Thanks very much in advance

It would depend on so many variables I doubt any average lifetime would be meaningful at all.

Doing volatiles analysis by purge and trap I have had columns last 2+ years, doing semi-volatile analysis by direct injection I have had a new column go bad in a few days due to contamination by and unexpectedly dirty sample.

If your samples are clean and the solvent is appropriate for the stationary phase and you don't run up to maximum temperature often, then a column should last a long time. You may need to trim a few centimeters from the head of the column on a regular basis but otherwise it shouldn't be a problem.

If your injections are really clean like with headspace, they can last for thousands of injections, probably 10k-20k runs, before the baseline starts to creep and look ugly. Stay well below your maximum recommended temps, use high-capacity gas traps and change them before you need to, and your column cost-per-run is trivial.

Splitless liquid injections with ugly sample prep, not so much.

I agree with the other guys.

our columns for headspace and thermal desorption GC (low temperature, only volatiles injected) last indefinitely - I have only changed a column once in 2 years and that was due to somebody physically breaking it when doing MS source maintenance. The baseline always looks good and the QC samples always pass.

It depends on the temperature and also on how much oxygen is in your carrier.

If there are injections of tough matrices, a column may only last a few 100 injections.

As an aside is there a brand of columns that is seen as the "Gold Standard". I have used Agilent, Restek, Phenomonex, SGE and all seem OK to me. Is there anyone (not associated with a particular supplier) who swears by one in particular?

Most of the phase chemistry is similar across the brands.

I have used mostly Restek for the last 30 years and can say they do hold up well. I even had a sample flood a purge and trap system once so badly that when you opened the oven door you could see droplets of water all through the column. We baked it out over night at about 105C and the next day recalibrated and it just kept on going. That was the old Rtx-502.2 phase column.

On the other hand, I have done semivolatile analysis and had a sample with extremely high sulfur kill recoveries for the more fragile analytes like pentachlorophenol or benzidine that never came back after that one injection. But then most columns will suffer the same fate with something like that.

The only thing I miss with Restek is the old style cages where the column was suspended in strings. I really liked that setup, now they use the same cages as most everyone else and if you are not careful they column can spool off the cage and you have to re-wind it.

Column spooling - hate it!

I agree that there seems to be little difference between vendors. However, Restek has phenomenal customer service, an excellent website, and their tech support is first-rate. So they are my preferred vendor for columns and supplies.

J&W (Agilent) makes a fine column as well; no experience with their tech support, and putting in an order is slightly more onerous than Restek.

Carrier gas with oxygen or water in it will kill columns quickly.