By ms on Friday, July 18, 2003 - 03:25 am:
For large volume on column applcation in pesticide analytics (GC/MS) a deactivated FS column (J&W) is used as guard. It seems the deactivation is not too good. Using a thin film capillary column would be too expensive over the time.
Does anyone have an idea of how to solve the deactivation problem?
By Anonymous on Friday, July 18, 2003 - 05:34 am:
I think I have had similar deactivation problems with their columns.
Why not try another supplier?? (eg Restek).
By Aviv on Sunday, July 20, 2003 - 09:12 am:
I am also familiar with this problem and used 0.1 micron film such as DB1 with less activity. The problem with on column however is that the activity can originate from the matrix deposit. Furthermore, low volatility compounds may migrate to the analytical column and kill it in a short time (starting with tailing). Thus, you may reconsider the injection into a standard liner that is cleaned in the split time with high flow rate.
By ms on Wednesday, July 23, 2003 - 05:26 am:
Thanks for your ideas. The suggestion with the DB1 column is basically good but over the time too expensive.
By Anonymous on Wednesday, July 23, 2003 - 06:43 am:
I use large volume guard from Varian (part. no. CP8187). Varian specially developed this guard for large volume applications and has better deactivation than standard fused silica.
By ms on Friday, July 25, 2003 - 03:06 am:
Could you give a more detailled description (type of deactivation etc.) because I can't find the part number on the Varian online catalogue.