Does anyone have any information about reconditioning used GC injection liners? I have quite a
collection that I have accumulated over the years. Routinely these are replaced by new liners.
They can be cleaned quite readily by a chromic acid bath and rinse with large amount of
distilled water. I understand that this technique could lead to active sites and I was wondering
about how to go about reconditioning (or whether I have to)these liners?

A common silanization technique is to treat the glass liners with 5 - 10% dimethyldichlorosilane in toluene. After a 30 minute contact period the glass is rinsed with dry toluene immediately followed by a methanol rinse. After drying, you can pack the liners with silanized glass wool.

I hope this helps

Gilbert Staepels
3M Specialty Materials Markets Group
Antwerp - Belgium

Whether you need to silanize them or not depends on your application, the analytes involved, and the levels chromatographed. In the 70's, we used to clean our liners by running oxygen through them while heating with a torch, a quick wash in soap and water, acetone dry, and back to work! We were analyzing pesticides at nanogram levels. Nowadays, at sub-nanogram levels and with capillary columns, we use commercial de-activated liners.

We had a number of used liners commercially cleaned and de-activated, but I don't know by who, or if the service is still available. They work as well as new ones, though.

Restek will clean and resilanize liners as a custom procedure. The per-liner cost depends on the quantity you send in. If you send in ten, the cost is ridiculously expensive. If you send in 100 or more, the cost is extremely cheap. The cost varies between these two extremes.

Jim

Best to send them to someone like Restek. They can do it correct and save you many headaches. I've used them several times.

As I understand it, silianization chemistry based on Si(CH₃)₂Cl₂, applied in organic solvents at room temperature, will come off the glass surface when heated above about 250 °C due to dehydration and Si-O-Si bridge formation in the glass. Restek and others apply a high-temperature treatment that is more stable. I've often wondered if this is really the case -- anyone care to comment ?

John

I've done it both ways. I've let Restek do the resilanizing procedure and I've resilanized my own linears using 10% dimethyldichlorosilane in toluene procedure. I've never had an active site problem doing my own linears and it's alot cheaper. Just make sure the glass wool you repack the linears with is silanized also.

hope I helped

I have resilanized my own liners using 5-10% DMDS in toluene from Supelco/Aldrich for 30 min and rinse with toluene. Then rinse with methanol, dry with nitrogen and condition at 200C for half hour in the injector before hook up the column. It takes less than an hour to silanize 10 liners and just condition individually as above before use. It works very well and never has any active site problem.