Print Page - Fragmentation at 4.9 mz

Title: Fragmentation at 4.9 mz
Post by: ab123 on January 15, 2018, 02:02:05 AM

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?

Title: Re: Fragmentation at 4.9 mz
Post by: Jan Stanstrup on January 15, 2018, 02:19:15 AM

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?

Title: Re: Fragmentation at 4.9 mz
Post by: ab123 on January 15, 2018, 05:12:08 AM

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?

Metabolomics Society Forum

Scientific themes => Compound identification => Topic started by: ab123 on January 15, 2018, 02:02:05 AM