Saturday, January 6, 2018

What can you do with a 213nm UVPD? Deuterium localization!

Sometimes hardware companies roll out new scientific tools because they seem like a cool idea and then -- it's our job as mass spectrometrists to figure out if it's useful for anything. I feel like this has been the case with a certain 213nm UVPD option that was released at ASMS this year. (Yeah -- some top down fragments and localization of lipid double bonds is cool -- but what about proteomics?!??)

This study ASAP at JPR shows another potential application of this technology! Deuterium localization within peptides. This could be incredibly useful for increasing the resolution of protein structural studies that use HDX.

This team obviously knows what they're doing and pushed the hardware they have to it's very limits. To get the UVPD fragmentation spectra using a TOF detector they combine spectra for what appears to be around 2 minutes. I haven't ran one like this in quite a while. I can't remember if the spectra are averaged or additive and the Supplemental info doesn't clarify, but that doesn't really matter. What does is that the result of combining all these spectra is convincing evidence of the deuterium localization because the output spectra almost looks like it was acquired on a high resolution instrument.

The team also works with accumulating fragmentation ions with CID, ETD and ECD and shows that a combination of these techniques can really help you lock down that heavy H localization. It's a really nice proof-of-principle study all around and another reason to break out that laser!


  1. Dear Ben,
    Thanks for the post on our work. Maybe point out the work was not on a commercially available product...
    Perdita Barran

  2. Hi Ben,

    I enjoy reading your perspectives on current literature and MS related stuff.

    I am co-author on a recent paper in which we show that low pressure UVPD can actually result in the hydrogen labeling becoming randomized (a process termed hydrogen scrambling). It turns out that UVPD at low pressures may behave more like CID, producing dominant b and y ions
    in which the hydrogen labeling has scrambled. Whereas slightly elevated pressures produce dominant a and x ions without hydrogen scrambling as in the paper you mention here. Our experiments were done on a commercially available UVPD implementation.

    I'll provide a link here if you are interested:

    Best regards,
    Daniel Wollenberg