Chromatography Forum

Hello everybody!

I'm trying to analyse TCE by GCMS using a ZB5 column. However I injected up to 50 ppm of TCE in MeOH and could see no peak on MS. Any suggestions on what can be happening? The injector temperature is 250oC and the SCAN goes from 30 to 300 uma. Colunm starts at 35, for 5', up to 200oC by 2.5oC/min. I started cutting the solvent at 3 min but then decided to short it to 1 min since I was thinking that TCE could be eluting in the dead volume but then I can only see the peak of solvent, that is splitted in 3. Any ideas?

Thank you a lot!!
Adriana

On that type of column, TCE would elute after the methanol, so look for peaks after the solvent front. Are any other analytes not showing up? Any recent changes to the system? Try increasing the sample concentration, reducing the split ratio, or increasing the injection volume to see if you get a peak at all.