PCB in caulking - closing calibration fails

[cjm]

I hope that someone can help me with this problem, our lab is running PCB in caulking samples by GC/uECD and the closing calibration standard fails because the signal goes through the roof and swallows up every compound and never returns without performing serious serious maintenance, changing liner, guard column, presstight-Y connector..not to mention the samples need to be re-run. We think the cause is from major matrix interference and we're not sure what to do. We're running splitless with a siltek drilled uniliner. I suggested to the other analysts to try a liner with wool and see if that would trap heavy contaminants. Any thoughts?

[tlahren]

I know you are already investigating better acid cleanup for other methods. Are you also using it for the caulk samples? I remember running into problems with caulk samples where extracts seemed to be clear but there was obvious interference in the chromatogram. Maybe acid will not remove these types of materials. You might want to try acid/base silica gel column. It's a little more work and maybe too costly for contract lab analysis (assuming that's what you're doing) but it's worth a try to see if it helps your chromatography by keeping the junk out of the GC. Let me know if you want to try it and need help setting it up.

Ty