Aftermarket high resolution FAIMS allows separation of MEGADALTON protein complexes!

 

FAIMS gets a bad wrap because most of the commercial systems have a resolving power of something between 5 and 20. They're great systems if you just don't want to fragment (or see) +1 ions and you want your mass spec to only see +2 or +3 ions. Cleans up your spectra so your mass spec doesn't have to work as hard, and everyone is happy at the end.

But....is that a limitation of FAIMS technology itself, or is that what is mass 😁 produced for the general market? Sure sounds like it's the latter. 

In this new study an aftermarket/custom high resolution FAIMS system was coupled to a UHMR (which has an upper mass limit of 80,000 m/z? Is that right? That's huge) and oligomers of antibodies (so a monomer is around 150,000 Da!) were coupled. 

The study is maths heavy and there are a lot of formulas, so I found it hard to get to the effective IMS resolution. However, this 2019 study indicates that the FAIMS is >100 resolution, and I think the two devices are similar. 

And - get this - you can get this FAIMS system for the front of just about any instrument and they can be custom tuned for small molecules, peptides, or intact proteins. And they're a lot less expensive than the 10 resolution units that you can buy for only certain instruments.