Wednesday, February 19, 2014

More evidence -- DMSO study on the Q Exactive!

Early this morning I received an awesome Powerpoint describing results of another DMSO comparison.  This time it was for a TMT experiment performed on a Q Exactive instrument.

The work is by Dr. Henrik Johansson and Dr. Rui Branca of the Karolinska Institutet and my colleague Dr. Michaela Scigelova.

Guess what?  DMSO additives in buffer reproducibly increase peptide/proteins in the QE during nanospray applications.  Interestingly, it isn't to the same degree as the increases we have seen in the hybrid platforms.  I obtained permission to distribute the document this afternoon, so I'll put a direct link here until it is published on Planet Orbitrap.

Adding DMSO led to 69% increase in +2 charge state peptides.  This is particularly cool, because TMT labeling tends to increase the peptide charge state (which can translate to a decrease in sequencing effiicency)

Adding DMSO led to a 17% increase in unique protein IDs.

Interestingly, comparison of the same sample ran twice, DMSO vs. normal buffer = new peptides!

Makes me wonder what those of you with super fancy multiple pump nanoLCs could do with this information....

Now, as always with this buffer additive -- I want to strongly caution you.  We do not have longitudinal data yet to fully realize the implications of this (or any other) buffer additive on nanoLC pumps, seals, or even the MS system itself.  Please follow the guidelines and specifications for your particular LC, source and instrument.  When in doubt, always please contact your respective vendors and technical support lines.  Also, please refer to my Disclaimer statement regarding this and any other advice you obtain through this blog.

You can download this incredibly informative and thorough analysis here.

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