[Mimic]

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: 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

[pgk]

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?