I have a intermittent problem when replacing injector liners. Lots of tailing for ethanol and other low alcohols - good shape for hydrocarbons etc.
I am using split injection 100:1 0.1 microlitre DB5 30m x 0.25mm x 0.25micron. My supelco non-polar test mix is OK save some tailing in solvent and octanol. I think the problem is liner activity. I have tried untreated quartz wool and silanised wool (not much difference). I have a PE PSS injector using a 2mm id liner. I have also tried other manufacturers liners.
Does anyone treat their liners prior to insertion with deactivating fluid?
Do you use a particular type of wool or do you treat it prior to use?
By Anonymous on Thursday, June 5, 2003 - 09:45 am:
If you are sure the liner is your problem, then I recommend you buy deactivated liners with the wool already in place. If you pack the liner yourself, you will create active sites on the silanized fibers because they break. If you wish to treat the liners yourself, then pack them first.
By Anonymous on Friday, June 6, 2003 - 04:47 am:
If you can change (increase) the film thickness, you may find that the alcohol peaks are much better behaved.
By jos vloet on Saturday, June 7, 2003 - 02:34 am:
If you indeed have problems with the activity of the liners you maybe can use our procedure.
For every analysis I use a new (the empty glass liners are bought from a glass supplier) glass liner. The liner was first filled with a propp of glasswool or not (depending on the application). After this we deactivate all liners with a procedure described by J. Hinshaw (in GC Troubleshooting). This is necessary because the cutted or broken glasswool has active sites.
After deactivation the liners are kept in stock in a desiccator.
By Bernd Mischke on Friday, June 13, 2003 - 07:00 am:
You should pay attention on the concentration of Your sample and sample amount. The idea with increasing the filmthickness is good. It is a tailing or a fronting? Sometimes it's good to cut the column 15cm, "activities" found after a longer using time mostly on the first cm'rs of a capillary column.
By Anonymous on Thursday, July 17, 2003 - 05:22 am:
Thanks for all your ideas. I have recently changed supplier of my column and have noticed much better results. I can't deny that my original columns may have been OK but this time the column comes flame-sealed and I made sure the column ends were cleaned in methanol. Trouble is, if you logically troubleshoot by changing one thing at a time other factors may still come into play.
Another related question would be:
When installing new column do you condition new liner first (without column attached) ??