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hydrogen as carrier gas in GC-MS
Posted: Thu Jan 25, 2007 8:35 am
by Peter Apps
A thread on the GC forum has evloved into a discussion on whether hydrogen is suitable as a carrier gas when doing GC-MS. Problems of pumpability, reactivity and explosions have been aired.
What do the MS experts say ??
Peter
Posted: Thu Jan 25, 2007 12:11 pm
by james little
used it seveal times when we couldn't reproduce the retention times of complex mixtures and correlate to our GC labs results.
No problems that I remember, should use same caution that one would use for GC.
Good link at
http://www.chem.agilent.com/cag/servsup ... afety.html
Posted: Sat Jan 27, 2007 3:21 pm
by ods-at-pacific
One important consideration in the use of hydrogen as a carrier gas in GC/MS is that hydrogen is not pumped as efficiently as helium by turbo molecular pumps. The difference is about 30% poorer performance with hydrogen than helium. There is no difference between the pumping of hydrogen and helium with an oil diffusion pump. The QIT GC/MS has the potential of being the instrument most effected by the use of hydrogen.
Posted: Sun Jan 28, 2007 8:40 pm
by viness
Application of hydrogen as gas - carrier in GC/MS results in strong change of mass - spectra terpenic alcohols. Usually it - reduction of intensity of an ion with mass 71. It occurs as a result of attack of a radical of hydrogen to OH-group and removal waters from a corresponding ion.
Boris Vinogradov (essential oil researcher)
Posted: Mon Jan 29, 2007 9:22 am
by HW Mueller
Boris, are you concluding from the results that a hydrogen atom reacts directly with the OH group to remove H2O, or do you have independent evidence for that?
Posted: Mon Jan 29, 2007 4:06 pm
by GOM
Boris,
On a separate issue, I am looking for someone to help me beta test a piece of software that I have been working on that identifies the amount and types of essential oils in a mixture of oils. I would need FID results from some mixed oil samples - would you be able to help?
Regards,
Ralph
Posted: Mon Jan 29, 2007 6:01 pm
by viness
Boris, are you concluding from the results that a hydrogen atom reacts directly with the OH group to remove H2O, or do you have independent evidence for that?
I did not carry out special researches. This my assumption.
Comparative mass - spectra terpenic alcohol (received in hydrogen and librarian) can be looked on viness.narod.ru/mass.htm
Posted: Mon Jan 29, 2007 6:24 pm
by viness
Boris,
On a separate issue, I am looking for someone to help me beta test a piece of software that I have been working on that identifies the amount and types of essential oils in a mixture of oils. I would need FID results from some mixed oil samples - would you be able to help?
Regards,
Ralph
Why not. My e-mail
vin-ess@mail.ru
Posted: Mon Jan 29, 2007 7:35 pm
by GOM
Great - thanks
Ralph