Chromatography Forum

After attending the seminar and hearing all the problems people are encountering switching to hydrogen for GC/MS I was wondering has anyone had a good experience?

Everything I am hearing is
I should expect 2 to 3x high background at least for the first few weeks
I should expect some changes to the EI spectra
There may be peak shape problems
I may need to scrap all my .25 columns for .18 columns

Has anyone had a straightforward switch from helium to hydrogen without major complications.

That's what I was afriad of

There are other issues to be aware of depending upon your application. For Environmental customers, tuning for BFB or DFTPP is a serious problem. The H2 does a great job of cleaning all the nickel surfaces, which can create activity in the injection port. This can cause Endrin/Aldrin breakdown and issues with phenols etc. Filament life is greatly diminished. Spectra can be changed which again, for environmental customers can be a challenge for primary calibration ions. We supply many instruments to the environmental market including H2 generators and right now, I would switch GCs but not MS systems....especially if you are running environmental applications.

You will rip through ion optic parts - the H2 does a great job of pitting your lenses. You'll have to polish your quads, as they have a tendency to get pitted at the entrance lens. You get reduced life out of the EM, and if you're running turbos you get about 1/2 the pumping efficiency that you do for helium, plus the H2 makes the vanes very brittle. In short, it's a great way to tear up your system.

Regarding using hydrogen as a carrier gas on Mass Spec: I talked to a service tech a couple days ago from Agilent and she indicated that If you use Agilent to do your service work, they have to change the carrier gas to helium to do diagnosis. That sounds kinda weird so I'm not sure if that is accurate.

Hey mckrause, what application did you try the hydrogen carrier for GCMS? I saw that you are from ATX and was just curious. I use to work environmental in Austin 2 years ago.

We use our MS as general GC detectors, so they're involved in a wide range of analyses; ranging from petrochemical to environmental to food pesticides. We run them pretty hard.

The spectra change with H2 (obviously, since you're also essentially running a low pressure CI system), so Agilent would have a difficult time looking at PFTBA under H2 conditions. We found that the autotune was useless - we had to tune everything by hand (which you have to do on a 5970 anyway). Positives are that you get a greatly enhance M+1 peak, so if you're dealing with aliphatic hydrocarbons it can prove to be quite beneficial. Conversely, if you're trying to run routine environmental analyses to USEPA specifications it can be extremely frustrating.

In general, our experience was that the maintenance requirements went through the roof. Since He is just not that expensive we didn't think it was all that viable at the time. If He becomes hard to get (not the case in Austin) then we'll take a hard look at it again.

Our local PE rep clsims it does not work yet with PE systems.
I use H2 on most of my GC's but fames for example get hydogenated.
Unless you change liners every tome.

mckrause

Were you injecting chloroform or methylene chloride while running hydrogen? At the Agilent seminar the point came up that if you do so you can generate HCl gas in the instrument and that definitely will wreck havoc on the instrument as you describe.

MSChemist and all
Aviv Analytical launched recently a Blog journal for Advanced GC-MS:
http://blog.avivanalytical.com
In it a recent note is about the Helium Shortage and Hydrogen as a Carrier Gas for GC-MS

Amirav

Thanks folks, this has all been useful.

Amirav, from your blog post, it sounds like hydrogen carrier can be a problem for some pesticides as well, regardless of the detector?

Yama001
Indeed "hydrogen carrier can be a problem for some pesticides as well, regardless of the detector"
I worked with a GC-PFPD and the hydrogen induced degradation is mostly at the injector. I can send you (or anyone else who is interested) a paper on those GC-PFPD results if you will write me
at amirav@tau.ac.il
Amirav