My coverage/guest blogger coverage of the COVID superspreader event otherwise known as ASMS2022 was impacted by some craziness in my schedule and the fact that no one I know has felt very well recently for some reason. I’ll do some backtracking as I find time.
On the hardware front, one move that likely only will surprise you because you probably assumed a ZenoTrap on a SCIEX QTOF would be able to do ZenoTrapping + SWATH, SCIEX rolled out ZenoSwath. The one in our lab (proof it is here in the only mass spec lab in the world with magic pink carpeting [magic because it keeps the asbestos in the floor and out of our lungs!] can’t yet ZenoSWATH, so we are puuuuuuuuuuuumped for that upgrade!)
The ZenoTrap is inline after the quad and after the collision cell and right before the TOF. The physics of the ZenoTrap is really cool because it essentially slows the ions into accumulation rather than pushing them to a dead stop with a hard gate. This is super important for my stuff because it compensates for the small time of flight effect of fragment ions of different sizes, allowing the ZenoTrap to eject both high and low mass fragment ions into the TOF in one go. Somewhat less important for most SWATH experiments, but a feature that helps me out a lot.
It looks like from the online info that you do necessarily have to lose some speed when using ZenoSWATH vs regular SWATH, but 133 Hz isn’t all that bad for a 10x boost in low abundance signal.
This is an aside because I just got data from this. I’ll be honest, while EAD and the E-I-E-I-O fragmentation stuff sounded like a neat trick (giant magnets force a charge onto your peptide and you get ETD/ECD fragmentation — you can actually use your phone to detect the magnets, they’re that powerful) it wasn’t why I wanted a 7600. I need higher intrascan linear dynamic range. I had some open time on Sunday night and reran some leftover samples with EAD and….it’s probably the best looking ETD-type spectra I’ve ever generated.
This is following using a non-fragment filter and exclusively plotting c/z ions. I’m not picking and choosing, they ALL look like this. I don’t have any good PTM data, I just used it for regular old peptide ID. I’ll drop some comparisons that make sense later!
