Page 1 of 1
Method for detecting CO
Posted: Fri Jul 29, 2022 6:27 am
by szsayyed
I have a GC equipped with Mol Sieve 5A and a TCD and N2 as an carrier gas. I have tried different combination of oven and detector temperature but i am not able to detect CO. What conditions should i use to detect CO?
Re: Method for detecting CO
Posted: Fri Jul 29, 2022 6:37 pm
by 70 eV
Used to run ASTM D-1946/ EPA 3C. We used a GS-GasPro column, argon carrier gas and ran with cryo. Starting temp was -80.
Re: Method for detecting CO
Posted: Sat Jul 30, 2022 2:04 am
by AICMM
szsayyed,
A mol-sieve should separate CO - typically later in the chromatogram - unless the column has been badly abused.
The bigger question here, I think, is at what level. Using nitrogen as a carrier, the sensitivity to CO will be poor - probably low percent realistically.
If you are looking that low or lower, you should consider switching to helium or hydrogen as the carrier in order to gain sensitivity.
Likewise, keep the detector cooler if you can - on the order of 175 or so.
Best regards,
AICMM
Re: Method for detecting CO
Posted: Sat Jul 30, 2022 8:13 am
by szsayyed
Dear sir,
I have tried injections with pure CO as well at TCD temperature 140 degrees. but even then theres no sign of a peak
Analysis is performed on the new column
Re: Method for detecting CO
Posted: Sun Jul 31, 2022 8:08 am
by antonk
Dear sir,
I have tried injections with pure CO as well at TCD temperature 140 degrees. but even then theres no sign of a peak
Analysis is performed on the new column
As was mentioned above - try lower temperature. Without cryo -80 is not reachable, start at +40 in oven.
Looks like your peak is very broad and not seen as a peak.
Also very hot TCD may decrease sensitivity, try +90.
Re: Method for detecting CO
Posted: Mon Aug 01, 2022 8:02 pm
by AICMM
szsayyed,
Let's start simpler. If you inject air do you get an early, good sized O2 peak?
Best regards,
AICMM
Re: Method for detecting CO
Posted: Sat Aug 20, 2022 10:35 am
by szsayyed
No sir i did not get an O2 peak at the beginning
Re: Method for detecting CO
Posted: Sat Aug 20, 2022 11:14 am
by szsayyed
szsayyed,
Let's start simpler. If you inject air do you get an early, good sized O2 peak?
Best regards,
AICMM
I could observe a small peak at tha begining but not a huge one
Re: Method for detecting CO
Posted: Sun Aug 21, 2022 9:38 pm
by AICMM
szayyed,
Which TCD are you using - what vendor. Some of the TCD's use range settings to moderate sensitivity so I am wondering if that might be an issue. The other think I would suggest, if possible, can you inject an aliquot of hydrogen and see what kind of response you get from that. That would certainly tell you if the TCD is dead since, against N2 carrier, it should give you a great peak.
Best regards,
AICMM