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- Posts: 102
- Joined: Tue Oct 06, 2020 10:01 pm
- Location: Australia
1. Significant carryover of high-boiling compounds (e.g. about 50% for naphthalene). I bumped up the desorption time somewhat but to no avail.
2. Surrogate response gradually increases over a sequence of runs, but internal standard response remains fairly stable. I found this odd because the internal standard and the surrogate are dosed similarly.
The instrument is a Tekmar Stratum with an Aquatek 100 autosampler, injecting into an Agilent 6890/5975 combo.
Any ideas what could cause these issues? I don't remember whether or not I replaced the trap in the Tekmar when I installed the instrument, but just wondering if there's anything that immediately stands out as possibly wrong.
I had another unusual issue as well in that the internal pressure was well in excess of 30 psi and adjusting the internal regulator in the Aquatek did nothing to throttle it back. I ended up having to put an additional regulator in the line to restrict it to the 6 psi that the Tekmar wants. Not sure what could have caused this aside from a faulty internal regulator in the Aquatek autosampler.