Fascinating.
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Volume based loading. Between 1 and 4 nank liters was good for me.
So excited yours is getting there. Mine doesnt even have a desk with electricity yet.
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I’m super super excited. I probably have 15 hours into futzing with it at this point, definitely could have had it running in January if it had made the priority list, so I know exactly the position you’re in.
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Okay so after a long, frustrating day I’m getting damn close. I officially am reading a spectra, so that’s neat. Unfortunately it’s a spectra for water lol.
Looks like I’m pretty much leak free but so much time with the column off probably means the inside of the trap is pretty wet. So I went to bake it out and learned that all my time switching the machine over to 110v was in vain because there are different heaters entirely for 220 and 110. Fuck.
Break out the ladder and electrical gear, had to run a new circuit of 208 over to the lab because I don’t have any in that room. Out come all the boards again so I can switch all the switches back to 220v. At the end of the day, I probably should have just run the new ckt in the first place, that’s what you get for trying to be clever I suppose.
With the new power hooked up, the heaters seem to be working (although the manifold heater still seems pretty slow). @Cassin, any idea how long it should take that thing to get up to bakeout temp if it’s working properly?
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Not any more than an hour…
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Good! It was late and I got sick of watching it creep up after about 90 seconds lol. Hopefully I don’t come back to another “failed to reach temperature” error in the morning.
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Where did you buy the autosampler?
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Ebay!!! Lol I’m such a scrapmonger. If only I could find the damn cable or an example of the pinout so I could make one up
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Spent most of the day checking for leaks and baking shit out, still showing too much water. Looks like I’m going to have to disassemble the trap to get it clean. Been able to go through most of the calibration successfully but there’s just way too much noise. Here’s what I’m seeing with just carrier gas:
On a different note, I’m trying to figure out where to set the trap/transfer line/manifold temps. I assume the transfer line should be around the same temp as the final column oven temp but the other two I have no idea on.
Also, what’s a reasonable baseline signal? <10 counts? <100?
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That’s a signal of what? What does the chromatogram of overall run (not mass spectrum) look like?
Well before I started turning the column temp up on the old piece of shit SBP-1 of unknown age I was getting a pretty nice flat line around 80 “count” (I assume this is supposed to represent the actual number of ions within the scan range per scan?). Then I started turning it up and it got running as high as 180k lol. Which I have deduced is high enough that you can’t really see an injection spike it it, so that’s gotta get fixed.
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So, I was down to 0.6 m/z on the air test and 125% 18/19 on the water test (which is still “massive”) but I was still seeing some stuff at 73 m/z and some weird heavier stuff so I decided fuck it and tore the trap apart. Kind of crazy how simple these things really are inside. Cleaned everything with alconox then solvent washed with methanol and baked it out. Reassembled the unit and have it baking back out again. Hopefully that’ll handle the weird peaks. Water level is still testing high but that’s no surprise since disassembling the trap (no way to bake out the housing itself).
On another note I was reading an Agilent article today that was showing baseline at like 4000 “count” so maybe my 80 baseline was already pretty damn impressive lol. @Cassin any insight? I could use some context from someone who’s run one of these. Unfortunately it seems like @iontrap might not be commenting on this forum anymore which everything else aside is a shame because it seems he’s rebuilt these traps more times than anyone else.
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Perhaps @kcalabs may have some insight regarding the baseline
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I’m guessing that it’s fairly different for an ion trap than a quad (the latter being much more common and allegedly having slightly lower resolution). I’m not sure what @kcalabs has for GCMS but any insight at all would be appreciated regardless
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I’ll ask around tomorrow, but you’re probably right about the leaks.
Yes - really damn impressive. I’ve seen them much much higher and still passing everything. That will also depend on what your method will allow for signal to noise ratios.
You should be able to put the damn thing together - turn up the oven and back it off while its assembled. If the system will allow you to do so (sometimes it won’t due to pressure.)
Do this while the MS is not inline or connected to make sure you aren’t just shoving crude in.
You should also make sure you have a water trap and air filter on the incoming air from your tank. Sometimes the lines can be wonky, especially if temperatures are weird or your tank supplier is not the best.
Also - you can always use what you have! Then you validate your method specific to what your system is capable of doing. You might have less resolution - which means you may need longer run times or you cannot get your LOQ as low as you would like.
Even when things are messy - there’s always ways to use the instrument and learn. On the pressure side - I always just record what is “normal” that can be anything for your system. Its your systems normal - which can change with different types of columsn, different kinds of ferreles, etc. You know?
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Okay so still getting ~125% 18:19 aka “massive water” so I replaced the pencil filters. Still no dice. Has to be a leak. So I started going through they system and then I did something massively stupid:
Apparently, if you overtighten the column ferrule, you can get a very small piece of vespel ferrule jammed in the through hole from the injector. Fuck. 3 hours of fucking around later, I have not been able to dislodge it. 100 psi of helium hasn’t done shit. If anyone has a pro tip about how to unfuck this situation I’m all ears lol. I’d really like to not further destroy this injector
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Can you show a picture of the issue?
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Acetylene torch tip cleaner?
I feel you
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