This new method/paper at MCP makes a ton of sense and it should possibly bum us all out a little.
The thing we all love about PRMs (PARALLEL reaction monitoring) is that the upfront setup is so easy. Put in the mass of your targets, maybe the retention time in your instrument method if you're fancy (or want a much larger number of targets) and run it. Chances are you can find 2 or 3 good fragment ions from your target at/around your measured or predicted retention time to use for very selective quantification.
On a low resolution targeted system like a triple quadrupole system it's a lot harder. You need to know your retention time well and you generally need to optimize your collision energies so you get a couple of really good fragment ions. BOOOOOOOOOOOOO.
However, in the back of all of our heads we all know that peptides fragment differentially based on their sequence, length, etc., etc., and we could probably get more signal out of our PRMs by optimizing more (ask the small molecule people if you don't believe me).
This group finds tremendous gains in sensitivity by optimizing their PRM settings individually. Collision energy makes total sense to me. Particularly for the weird nontryptic peptides that are the focus of the study. I'm not as clear on why the quad isolation is adjusted as a function of the parent ion m/z.....I guess if it's a big +1 you use a bigger window to capture the M+1 isotope. Actually. That probably is it.
Sounds like a complete drag, right? THEY AUTOMATED IT! And you can get the scripts!
No comments:
Post a Comment