Chromatography Forum

Hello everyone, I've seen a few posts about autotune failures and have a couple of specific problems that I could use some help solving.

My MSQ+ stopped showing peaks in the SIMS after about six months of usage. During the six months, the cone was cleaned regularly and I didn't have any issues. The front end IC is working and verified by the conductivity trace.

On Thermo's recommendation, I've tried multiple times to autotune the system. Here's the confusing part - most of the calibration passes. My 773.35 reference peak always reads low. It's throwing off the whole thing. All of the other reference masses are OK.

I've already thoroughly cleaned the system and replaced the capillary but the results are the same.

Two questions:

If the autotune fails on one mass, does it store the data for the others? I don't actually care about masses up by 773. I'm really only looking at ~100-250 with SIMs.

Can the 773 be removed from the autotune protocol? I've seen a little information about editing the parameters in Notepad but haven't tried yet.

I suppose I should throw in a third question of any other ideas to try?

Thanks for reading.

You should do some more cleaning: Remove the source block and clean the RF/dc prefilter in a 500 mL measuring cylinder filled with water, then with methanol. Leave it to dry, then reassemble everything. Even if you don't see any dirt on it, this really helps (at least it does for me). The source design of the MSQ has really high risk to let the spray enter into the cone.
See the manual (page 87) on how to dis- and reassemble everything.
One more thing to improve signal quality: Go get yourself the cheapest syringe pump, and infuse the calibration solution with 10 µL/min directly into the source. This loop-filling and pressurizing approach is ridiculous. (I guess it's obvious that I don't really like my MSQ )

Kind regards
Jörg

I've taken the quad and everything else I could get to out for cleaning and that didn't really do anything.
I do like your idea of using a cheap pump pump to infuse the calibration solution! I've never liked the pressurized bottle approach either.

Thanks