Chemical Forums

Chemistry Forums for Students => Organic Chemistry Forum => Organic Spectroscopy => Topic started by: Mimic on May 24, 2018, 06:35:58 AM

Title: Mass spectrum: 2,3-dimethylbutane peak at 55
Post by: Mimic on May 24, 2018, 06:35:58 AM

What is the peak at 55 m/z? http://sdbs.db.aist.go.jp/sdbs/cgi-bin/img_disp.cgi?disptype=disp1&imgdir=ms&fname=MSNW1293&sdbsno=654

This is my idea

86 - 55 = 31: what can it be 31? or
secondary fragmentation from 71 (https://i.imgur.com/6qSIgNf.png): 71 - 55 = 16. Can be a loss of a methane molecula? If so, what is the structure of the ion at 55?

Thanks in advance

Title: Re: Mass spectrum: 2,3-dimethylbutane peak at 55
Post by: pgk on May 30, 2018, 12:29:19 PM

If there is migration of an hydrogen radical, then the molecular fragment is M/z = 85.
Can this lead to a fragment m/z = 55?