Brand new Xevo G2-S Q-TOF data...looks messy

[dkotes]

Our lab just got a brand new Xevo G2-S Q-TOF and the machine is probably being used to 1% of it's true ability.

Anyway, I've always noticed that TOF total ion chromatograms just never look as nice as triple quad TIC's. When I run a sample on the triple quad, each peak generally corresponds to a particular m/z and the smaller fragments. The Q-TOF data is just all over the place. It's made figuring out what's in a mixed sample nearly impossible. I ran a pretty standard acylation reaction using Meldrum's acid and Heptanoyl chloride, and literature (and my TLC) gave a high recovery and purity with a m/z of the compound +Na.

I search out all possible combinations of +H and +Na and I just see nothing.

Even a blank is filled with noise, and yes everything has been cleaned 10x over.

Caffeine as a standard looks fine, the UV is shark, the TIC is a rather tall and kind of broad peak, but the 195 m/z is the only one.

Reaction mixtures are just noisy and seem to have so many ions upstream and downstream when the peaks mass spectrum is selected.

Is that just the nature of a Q-TOF? Can switching to centroid from continuum have any effect?

It sucks having this new toy and just seeing so much noise

[carlo.annaratone]

I guess your problem might come from below-optimal parameters for centroiding and scan time. What settings are you using?

[McGyver]

Hi dkotes

Please see my post concerning LC-MS contamination of masses 117, 212 and 233. I posted my last reply there today. We've had the same kind of problem with our Xevo TQD since day one. I've been working on it now for a year. Please see is you see any of the masses in your background which I have described in my post. I guess you also have an Acquity UPLC connected to the MS? There might be no connection between your and my problem, but lets just make sure. Please let me know if you see any resemblance to my background on your system.

Regards,

McGyver