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Column temperature
Posted: Fri Jun 06, 2008 2:21 pm
by kankyo
Because of recklessness, I set the column temperature as an injector temperature. The column can be set at a maximum of 260 C but I pressed 350 C. I just noticed after about 5 minutes when the oven temperature has reached 350 C. I have heard like clicking sounds inside the oven and smelled something different. I immediately tested it, but I have not found inconsistencies in retention time and areas using my standard solution. Will I encounter problems in the coming days? Shall I going to replace it with a new one?
Million thanks..
Posted: Fri Jun 06, 2008 2:55 pm
by Consumer Products Guy
I'd compare chromatograms of a "known" run now v. those of same sample/critical standard mix made when column was "new". I'm assuming you have a brand-new column in the drawer for back-up/next use, a good practice. Yes, you got the column hotter than recommended. Yes, carrier was flowing, not just column containing air. Yes, it was only a short time. Only you can tell, through comparison testing above, whether the column is still appropriate for use.
Posted: Fri Jun 06, 2008 2:57 pm
by JoeJoe
I think your inside clicking sounds inside the oven are due to a dilatation of materials ! Smell too. I think you can work without problems.
Regards,
Joe
Posted: Sat Jun 07, 2008 2:08 pm
by kankyo
Just today after having about 40 runs, I found that the areas of the peaks I got have increased by a factor of 2 or more. I tested this for all the standards that I am using. There is no change in the retention time and the quality of the peak. I also got very good separation. Could this be the outcome of column deterioration?
Posted: Sat Jun 07, 2008 5:31 pm
by Victor
There are some older methods of column preparation which involve heating stationary phase films to a temperature approaching or higher than their maximum operating temperature in order to deactivate active sites on the column. This was particularly done with Carbowax 20M columns (polyethylene glycol), but also with silcone phases when I think the process was called "polysiloxane deactivation", first proposed by Schomburg. The idea was supposed to be that the stationary phase or even its decomposition products covered active sites on the column (like silanol groups). THis method really worked and may still be in use. So maybe you have deactivated your column a bit... I would not worry if your method is still working.