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Varian 3800/1200L On H2(and other general questions)

Posted: Tue Sep 10, 2019 2:45 am
by benhutcherson
I'm trying to get set up with a GC-QQQ, and right now for a variety of reasons a 1200L is coming to the top of the heap.

I know this is an older system, but do have some Varian experience so it doesn't scare me off too much and the price is right on it.

As a bit of a preliminary question, does anyone know of a source for filaments? I know SIS can rebuild them for a reasonable price, but I'd like to have a few spares on hand so that I can at least cycle through a few before sending some to then.

As a secondary question, though, I'd like to start this system off on H2. It's going in a different room from my other GC-MSs, so I'll be plumbing it in separately. I know H2 is a no-no with Saturn ion traps, but haven't seen any similar cautions on the 1200Ls(whether single or triple). Does anyone know whether or not they're okay with hydrogen?

Re: Varian 3800/1200L On H2(and other general questions)

Posted: Fri Nov 08, 2019 5:43 pm
by benhutcherson
I FINALLY have order confirmation on this instrument and hopefully will have it here within a week or two.

I still don't have an answer on H2, so am going to stick with He for now.

In the interim, though, I thought anyone coming across this in a Google search might be interested to know that Agilent does still stock and sell the filaments for this instrument. They were a bear to find, and I probably wouldn't have dug them up if Ron at SIS hadn't given me the P/N-it's 9300000400. ... 9300000400

As I write this, they're a whopping $311 each, which means that once I have a stockpile of good filament bodies SIS will definitely be getting my business to rebuild them rather than replace outright.

Also, Ron at SIS advised that the single most problematic part on them seemed to be the source cartridge heaters, and advised that they can supply a replacement. Old threads on this site indicate that this has been a problem since these instruments were new and current.

Otherwise, though, I'm actually really happy to go with this for a QQQ. Among other things, AFAIK all have CI, which to me is a big selling point on a QQQ and is an option that will add ~$50K to an Agilent or Thermo instrument. Also, Thermo likes touting their vacuum interlock for source cleaning, but these instruments have that also(all have it-it's not an extra-cost option like on Thermo instruments). I'm not totally clear on this, but it seems to me as though the same interlock that allows you to clean or change the source without venting would also allow column swaps.

Re: Varian 3800/1200L On H2(and other general questions)

Posted: Fri Nov 08, 2019 6:25 pm
by James_Ball
We looked at one years ago when looking into doing a CI method and I believe it will work for doing a column swap.

I think the interface is similar to what was on the old HP-MS Engine for doing column swaps while keeping the instrument under vacuum.

Re: Varian 3800/1200L On H2(and other general questions)

Posted: Mon Nov 11, 2019 5:11 pm
by tdgcuser
I’ve got two of these and several new and blown filaments. SIS can also supply the EM. You have to vent to change the column, or it will vent for you. Column placement is a bit tricky, I do it by feel. The source can be changed under vacuum, get extras if you can because the source volume is very small and they get dirty so fast.

Let it pump down for a while, heat the manifold up to 55C. after about two weeks, return to 40C and the vacuum should be about 3x10-7.

I haven’t tried H2. There is a neat feature where the MS purges the source with helium during the solvent delay, does a nice job of getting rid of the solvent.

Overall, these are pretty solid, robust instruments and easy to repair. I keep threatening to replace them if they go down again, so they keep chugging along. There are some former varian guys who will help with board repairs who monitor this site.