5973 Won't Complete BFB Target Tune
Posted: Thu Jun 27, 2024 12:54 pm
I've been testing a spare analyzer/sideboard assembly I have for a 5973.
I'm running EPA 522 on this instrument, so normally do BFB target tune followed by a BFB check and then usually some small tweaks(I'm running hydrogen, so 96 rarely passes without me tweaking the tune).
I put this spare analyzer in a week ago to test. It's pretty much undisturbed off a parts instrument-actually I should say I'm using the vac manifold/turbopump that this side plate was originally paired with(the sideplate I normally use started life on a diff pump instrument). I do not have a source that came with this analyzer-I'm using the source I've been using all along that's known to be good.
I did a pumpdown and 72 hour bakeout on this analyzer, and on the whole it passes autotune(atune) great with the EM at around 2K volts(~1950 with the quads negative, ~2030 quads positive), low air/water background, and good peak shape. It's giving me ~4.8x10-5 torr at 1.4mL/min H2, which is a little high for this instrument but a reasonable vac level in my book. I dipped the coils, but ended up maybe making 1/16 of a turn if even that much(and RF voltages look good compared to other insturments I've run).
I can't quite figure out what's going on with BFB Target, though. The PFTBA valve opens(confirmed by an audible click and manifold pressure goes up to ~5.2x10-5) but I basically just get grass on the profiles and flat lines on the ramps. I don't know if it's that it's starting with parameters from my other analyzer, but it will fail BFB target every time. I can turn right around and get it to pass autotune fine, so to me it seems that everything should be working. It's just...not...
Any thoughts on this?
Also, unrelated, but does anyone have a way of doing an actual BFB tune on this instrument? The BFB I have is a solution in methanol, and I'm not sure if there's a good way to introduce it into the vac chamber. I know the software(MSD Chemstation G1701EA E.02.02) has an option to tune on BFB but of course there's no way to do it. Can one use pure BFB in a spare calibrant vial? Stuff a liner with a bunch of glass wool, set the inlet to a low temp, and inject a bunch of BFB into it so that it slowly goes into the column? SOme other way I'm not thinking of?
I'm running EPA 522 on this instrument, so normally do BFB target tune followed by a BFB check and then usually some small tweaks(I'm running hydrogen, so 96 rarely passes without me tweaking the tune).
I put this spare analyzer in a week ago to test. It's pretty much undisturbed off a parts instrument-actually I should say I'm using the vac manifold/turbopump that this side plate was originally paired with(the sideplate I normally use started life on a diff pump instrument). I do not have a source that came with this analyzer-I'm using the source I've been using all along that's known to be good.
I did a pumpdown and 72 hour bakeout on this analyzer, and on the whole it passes autotune(atune) great with the EM at around 2K volts(~1950 with the quads negative, ~2030 quads positive), low air/water background, and good peak shape. It's giving me ~4.8x10-5 torr at 1.4mL/min H2, which is a little high for this instrument but a reasonable vac level in my book. I dipped the coils, but ended up maybe making 1/16 of a turn if even that much(and RF voltages look good compared to other insturments I've run).
I can't quite figure out what's going on with BFB Target, though. The PFTBA valve opens(confirmed by an audible click and manifold pressure goes up to ~5.2x10-5) but I basically just get grass on the profiles and flat lines on the ramps. I don't know if it's that it's starting with parameters from my other analyzer, but it will fail BFB target every time. I can turn right around and get it to pass autotune fine, so to me it seems that everything should be working. It's just...not...
Any thoughts on this?
Also, unrelated, but does anyone have a way of doing an actual BFB tune on this instrument? The BFB I have is a solution in methanol, and I'm not sure if there's a good way to introduce it into the vac chamber. I know the software(MSD Chemstation G1701EA E.02.02) has an option to tune on BFB but of course there's no way to do it. Can one use pure BFB in a spare calibrant vial? Stuff a liner with a bunch of glass wool, set the inlet to a low temp, and inject a bunch of BFB into it so that it slowly goes into the column? SOme other way I'm not thinking of?