liner issues on GC-FID

[vorian]

Hi all, I am running a GC-FID analyzing volatile fatty acids. It is direct aqueous injections on a DB-FFAP column. Because of the nature of the samples (supernatant from digested sludge water) I have to change the liner routinely. The problem is that when the new liner (wool packed) is installed I have to "condition" the liner by running a series of low to high standards followed by 30 blank injections. If I don't do this I have a very noisy baseline and the areas of my lowest standard (12mg/l) will not meet. However, sometimes even after this conditioning step my blank sample (previously analysed as below LOD at 2mg/l) still reads above LOD. If anyone has any suggestions on how to avoid or rectify this it would be gladly appreciated.

[WillyOne]

Perhaps the use of silanized glass wool can help you. See Supelco catalog for this.