Chromatography Forum

Any advice/experience for liners in DDT/Endrin analysis would be appreciated. Specifically, any comments on observations of late -- I am confused because I ran DDT/Endrin standards with several different liners (differing deactivation chemistries) compared to a plain borosilicate tube of the same dimensions (no deactivation, but containing a glass wool plug of "pesticide grade" for vaporization of the sample) and the bare boro tube performed just about the same, and somewhat better than, ANY of the deactivated liners. (Breakdown was ~0.5% higher for the bare boro, but peak area was ~10% greater.)

I plan to try a bare quartz tube w/ pesticide grade glass wool and w/ bare quartz wool and a Sky liner when I have the time.

I would appreciate any comments or advice...Thanks.

I use the Restek direct connect liner ( havn't tried Sky yet) with good results. When liner is fresh I get total breakdowns of <1%.
I use an Agilent GC so the sample is exposed to the SS of the weldment which can contribute to breakdown.

I analyze pesticides by EPA 508/608/8081 and I have found that using a single tapered liner with a plug of glass wool in the center provides complete vaporization of the sample with minimal breakdown. I clean and pack my own liners which is considerably cheaper than purchasing new ones if done properly. I get 100 injections or more with < 2% breakdown by running a very high split ratio of 50:1. By running a high split flow you can quickly transfer the sample to the column and reduce the contact between the sample and the bottom of the hot injection port.