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Edit: Mass spec tunes fine though on the low end of spec, air/water check is fine
Edit2: I've re-run samples that had been run previously that didn't show a bunch of hydrocarbons and now they do
Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.
James_Ball wrote:
Another thought, try injecting pure ethanol and see if the peaks appear.
Since they didn't appear from an air blank or just blank run, maybe there is something stuck in the system that the ethanol from the wine is knocking loose. Inject it from a needle, just 1ul, not from the SPME fiber.
laytox wrote:
So just a follow up in case anyone else encounters this problem - it seems as though it is indeed contamination (which I suppose makes sense since everything tunes fine and there's not much noise in the tuning). Ran a blank with 15% EtOH and it did indeed look like the same contamination I was seeing in the samples, so it appears it's something that requires solvent to leech in to the system. We have an unused GC so we're going to completely switch out the inlet and see if that fixes things. Ran the samples on another GC and no sign of diesel-looking peaks (though the other GC is running a polar column, so there's still the chance that there's something weird about the sample itself).
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