High water % on tune with Hydrogen

[markf]

We've been working with a hydrogen generator for about 2 years now, so it's not the hydrogen cleaning.

When we changed to hydrogen tanks we kept the instrument on 1000 split to purge the gas lines faster, no improvement there.

[markf]

I've found this document:
http://www.agilent.com/cs/library/slide ... er_Gas.pdf

I've read in one of the earlier replies about the magnet that needs to be changed to be compatible with hydrogen. (Page 15)

Like in this document, my magnet is without a serial number, which means that it is not hydrogen compatible.

Could this be the cause of all our troubles? What does this magnet actually change? This is not documented anywhere else and the service rep was clueless about it, he sent a query to agilent to check this out.

Also, there's something about a lens that needs to be changed (Page 16), what would this change?

[markf]

Quick update: The rep found a leak in the transfer line, strangely the O2 and N2 % went up the hotter the transfer line got. The rep is on his way now with a replacement part. It'll solve part of the problem, will have to see if that'll solve all the problems.

Asking again, if anyone knows: What would be the change when changing to the new H2-compatible magnets?

[James_Ball]

I believe the magnet problem is caused by the material of the improper magnets not being resistant to corrosion by hydrogen, the proper magnets will be more inert. I was using a 5973 when doing my trials so that wasn't a problem.

The larger diameter drawout is used so that you have quicker elimination of the hydrogen from the ion chamber to reduce the amount of CI reactions happening. This will help the spectra you get to look more like normal Helium based spectra. When I was working with it I still couldn't get BFB to pass because I was getting a H added to one of the ions. DFTPP tune check for semi volatiles I have successfully performed.

[markf]

Welcome to the goodtune, home of the good tune



Tremendous improvement after the transferline change, and still waiting on the new magnet and lens, hopefully they will give me even better tunes and better sensitivity/resolution. At present I can barely scrape the 5ppb LOQ requirement for Volatiles, and the 100ppb LOQ requirement on semi-volatiles, the most problematic of which are the nitroamines. I understand that they're always problematic to analyse, but one can hope that they will perform later when the new parts are installed.

[James_Ball]

Is that 100ppb in extract for the semivols? If so that is really good.

If you need lower for the semivols, you may want to look into the large volume injection methods, just being able to inject 3-5ul would really help with the reporting limits.

[markf]

Is that 100ppb in extract for the semivols? If so that is really good.

If you need lower for the semivols, you may want to look into the large volume injection methods, just being able to inject 3-5ul would really help with the reporting limits.

First of all I'd like to say thanks, especially to you James for sharing your knowledge and experience!

And I'd like to followup with a question, your lab analyses water and wastewater using 8270/3510, right? Do you analyse acids too, or just base/neutrals? What do you do about the nitroamines, their loq's and recoveries are ... so,so...to say the least.