Chromatography Forum

Dear colleagues,

Could you help me to overcome the “Christmas tree” effect I’ve got performing my GC/MS analyses. A sample injected usually consists of organic acid, amino acid and sugar TMS derivatives, pyridine and chloroform or acetonitrile instead of pyridine/chloroform. The injector (Optic) is programmed from 70 to 250 degrees, initial column (SPB50) temp is 70 degrees. After a number of runs I’ve started to observe the “Christmas tree” effect in peaks. The column replacement hasn’t helped.
Could anybody tell me what might be a reason of this effect and how to overcome it?

Thank you in advance,

Urry

Hello Urry,

Chrismas tree is nice at the end of the year.. but not in chromatograms.
The reason why you see this may be in a to high injection speed, so that You get liquid drops on the stationary phase and in this way "multiinjections". Also the injection amount/ volume and the compatibility of solvent mixture and stationary ph. is important.
Try to control this values.

rgds

Bernd Mischke