Chromatography Forum

Hello my name is Juan Manuel, I´m working with PCBs in soils and sewage sludge.

I´ve worked with a column VF-5ms 30 meters and 0.32 diameter. The method is:

- Gas Make-up and carrier N2
- Pressure 5.5 psi
- Mode injection splitless 1.5 minutes after split 1:40
- Make up 40 ml/min
- Temperature injection 250ºC, detector 300ºC and oven 50ºC for 3 minutes, 20ºC/min up to 180ºC, 2.5ºC/min up to 280ºC after 10.5 minutes.

My chromatogram has bad resolution for pcb 28 and 52 I want to improve it.
And now I have a column CP-SIL 8CB PCB FS 50 meter and 0.25 diameter. I am trying translate the other method with this column but at this moment I can´t see nothing Peak.

My new conditions are:
- Pressure 24 psi the other similar. No peaks.

I´ve realise injection without split, more pressure 40 psi, more sample, and I can´t see the peaks.

¿What´s problem I can have?
- Column bad situation?
- The make-up isn´t good for this conditions?


I did the calculations whit software of translate.

Thank you very much for you attentions

hello!
I also tried this column.
I have a very positive, because it lasted very little.
A big help from the've Scanview.
however, if you can Montale in a fid and initta solutions concentate to understand se va!
If you need help we try ..

Did you have the solvent peaks? If not, probably your column has been plugged (at the inlet end) or something similar.

juaant,

Start simple. At 80C isothermal set up a long run. Shoot a microliter of DCM or chloroform headspace and see if this comes off at all. If no, do the same thing by hand to make sure not an autosampler issue. If yes, then how late. 50 meter column for PCBs is going to take a long time. Then we go from there.....

Best regards.