hydrogen as carrier gas in GC-MS

[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

[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

[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.

[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)

[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?

[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

[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

[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

[GOM]

Great - thanks

Ralph