Wednesday, October 30, 2013
TMT 10plex on the Q Exactive Plus!
Why, you ask? Because I am looking at data that you can generate from using the TMT10plex on the Q Exactive Plus.
Imagine a world where your isolation mass width is ~1 Da with no loss in sensitivity. Imagine that the reporter ions that you have on 10 channels for quan are resolved at 50,000 resolution at the reporter ion level (35,000 resolution setting). Wait. Don't imagine that part, here's a picture of a randomly selected peptide reporter pair at 1:2 ratio (honest to Gus, it is random, they all look this good!)
That has been what my last 2 days have been like. Lots of time thinking about how many iTRAQ 8 plex samples I have ran over the course of my career, and how little interesting data has come from them. The future is looking pretty bright.
By the way, the method that my friends and I generated on this amazing instrument is now uploaded to the Orbitrap methods database. Yes, the QE Plus is more sensitive and can handle a more narrow isolation width, but widen the window a little and this is how you should run TMT10plex on your Q Exactive.
Now, my disclaimer. Did the Ting et. al., MS3 paper show that narrowing the isolation window didn't help all that much with the reporter ion suppression? Yes it did. Ultimately the MS3 method is better. But narrowing the isolation most certainly does not hurt! All it can do is eliminate co-eluting species and improve your quan. And if you fall into my camp of people who need to run faster with more sensitive identification at all costs, even that of reporter accuracy, then we take the improvements we can get without compromising speed.