Methanizer and CO.. This is a question

[JOCAPEN]

Please...
I have a doubt due to:
- The injection of only methane I have a RT
- And the injection of CO with the 380C methanizer the product formed does not have the same TR previous injection (only methane)
- Why.....column carbosieve and PLOT

[chromatographer1]

Dr. Penteado

Is your methanizer at the head of the column or the tail?

If it is at the head then CO and C1 should have the same retention time.

If it is at the tail of the column then CO should have the retention time of CO, not C1, as C1 and CO will separate on a Carbosieve column and have different retention times.

best wishes,

Rodney George

[JOCAPEN]

Dr. Penteado

Is your methanizer at the head of the column or the tail?

If it is at the head then CO and C1 should have the same retention time.

If it is at the tail of the column then CO should have the retention time of CO, not C1, as C1 and CO will separate on a Carbosieve column and have different retention times.

best wishes,

Rodney George

Initially I would like to thank you and sorry for help ... But my doubts persist sorry ... methanizer are on the final two columns of Plot and Carbosieve .... but the C1 and CO should not be the same after RT action of methanizer .... Thanks a lot

[chromatographer1]

C1 and CO should have almost identical RT on a Porous polymer PLOT column, CO eluting just before C1 and then on a Carbosieve column the CO should be retained significantly after the C!. But the retention time difference between entering and exiting the methanizer between C! and CO should be nil.

The RT difference between C! and CO is expected and I do not understand your thinking on this matter. The methanizer should be considered a part of the detector. It should not be considered to affect the RT of the analytes of interest of the analysis.

best wishes,

Rodney George

[AICMM]

Dr. Penteado,

If this is a Wasson built instrument, you may see an "S" after the methanizer in the valve diagram. This is not a column, just a restricted transfer line.

As Rodney points out, the methanizer (if at the back of the column) has no significant impact on retention times so the RT of each compound is dictated by the column in front, PLOT or Sieve.

Best regards.