Chromatography Forum

Greetings

I work in a hospital toxicology laboratory and we use GCMS and GCFID instruments. We use Helium for carrier gas on all GC's and have a hydrogen generator that provides fuel grade hydrogen for the GCFID.

We have been offered a free agilent 6890 GCFID which we could use for a backup instrument but it has been setup to use hydrogen as the carrier gas. I would like to stick with hydrogen since the helium supply is getting short and expensive.

But to buy a new hydrogen generator to make carrier grade hydrogen is not an option due to budgetary reasons so we would have to use an ultra pure hydrogen G-cylinder tank.

Since we will eventually have to convert to hydrogen I really want to set this up using hydrogen for carrier gas.

Seeking advice on how to safely use hydrogen cylinders. From what I've read most small labs secure the tank next to the instrument. But then I've read a OSHA regulation that requires hydrogen to be stored 25 feet from any electrical device or even "concentration of people" (whatever that is). That of course would be impossible for any hospital lab.

Here is the OSHA link

http://www.osha.gov/pls/oshaweb/owadisp ... &p_id=9749

Thanks in advance for any/all responses

Mike

I am not able to view the link - but check on what they are calling storage. Once the hydrogen cylinder is hooked up to the instrument it is in use - not simply being stored. And I am used to having a hydrogen cylinder clamped to the bench, and standing within a few feet of my instrument. And if OSHA calls this storage - there are a number of us who need to know...

My lab currently uses a hydrogen generator but I keep several Hydrogen cylinders on hand as a backup. Our building is plumbed with hydrogen lines at every lab station and we keep the tanks stored outside. They are always hooked up and turned on in case our generator fails. If this happens our instruments will draw from the tanks. I know it can get pretty pricey but a generator is definitely the way to go long term. They require little maintenance and I have found that the gas from the generator is actually "cleaner" than the ultra pure we can get from our local gas vendor. If you add up the cost the generator is cheaper in the long run. All you do is add clean DI water and they are good to go!

How far away is the nearest outside wall to site it outside? Or can you add filters to your generator hydrogen to clean it up to the right spec?

Whilst not an expert on Agilent GCs , most decent GCs offer switching between carrier type just by entering the GC configuration and setting it. Hence any change from Helium to Hydrogen and vice versa is almost instant.

What is the capacity on your current Hydrogen generator ? Why have you not considered it for use on the second GC ?

I am not able to view the link - but check on what they are calling storage. Once the hydrogen cylinder is hooked up to the instrument it is in use - not simply being stored. And I am used to having a hydrogen cylinder clamped to the bench, and standing within a few feet of my instrument. And if OSHA calls this storage - there are a number of us who need to know...

They are not calling it storage. They say "Hydrogen systems of less than 3,000 CF when located inside buildings and exposed to other occupancies shall be situated in the building so that the system will be as follows:
In an adequately ventilated area as in paragraph (b)(3)(ii)(b) of this section.
Twenty feet from stored flammable materials or oxidizing gases.
Twenty-five feet from open flames, ordinary electrical equipment or other sources of ignition.
Twenty-five feet from concentrations of people.

etc etc

Mike

Whilst not an expert on Agilent GCs , most decent GCs offer switching between carrier type just by entering the GC configuration and setting it. Hence any change from Helium to Hydrogen and vice versa is almost instant.

What is the capacity on your current Hydrogen generator ? Why have you not considered it for use on the second GC ?

Our current Hydrogen generator does not produce carrier grade hydrogen, only fuel grade. We do use a standard moisture trap but I don't know the purity once it goes through that.

If I had my way we would just get a new hydrogen generator that produces carrier grade hydrogen but after all the medicare cuts and the "Unaffordable Health Care Act" there is no money for capital expenses.

Mike

Our current Hydrogen generator does not produce carrier grade hydrogen, only fuel grade. We do use a standard moisture trap but I don't know the purity once it goes through that.

As it starts from water your impurities will be water and Oxygen. Add traps for both and you should have "carrier grade" gas

That's just what I'm saying. What are your specs from the generator and for the carrier gas? Alternatively you could just switch to nitrogen or other carrier gas, it's cheap and safe to store/use (I don't want to kick that one off again about hydrogen BTW).