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Topic: Fragmentation at 4.9 mz (Read 426 times) previous topic - next topic

  • ab123
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Fragmentation at 4.9 mz
Dear Forum members,

My MS1 files are showing multiple fragments at 26 mz apart with a strong base peak in between them. The more fragmented MS2 (I mean MSe here since this isn't MSMS) files are then showing the same peaks shifted by 4.9 mz each backwards.

Any idea what this may be?


  • Jan Stanstrup
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Re: Fragmentation at 4.9 mz
Reply #1
4.9554 could be a Na+<-> NH4+ difference. https://github.com/stanstrup/commonMZ/blob/master/inst/extdata/adducts_fragments.tsv

26 I don't have a good idea for. What is it accurately?
  • University of Copenhagen, Denmark
Blog: stanstrup.github.io

  • ab123
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Re: Fragmentation at 4.9 mz
Reply #2
Hi Jan,
Yes, I did think NH4 to Na made sense, but it would occur at least three times in a row.

The 26 difference is 26.0225, also at least 3 times in a row...

And why would it all be shifted by 5 mz between MS1 and MS2?
  • Last Edit: January 15, 2018, 05:14:20 AM by ab123