Give the curved-arrow mechanism for the formation of each of the following fragment ions in Fig. 27.7 from an M + 1 ion.

(a) The fragment at m/z = 551.94.

(b) The fragment ion at m/z = 710.97

(c) The fragment ion at 727.09. Show how this mechanism might be tested with a deuterium-labeled peptide.

Transcribed Image Text:

relative abundance CH3(CH₂) 14 N 100 80 60 40 -acyl group (mass = 334)- 20 N=N molecular mass of the acyl group = 334 0 200 334.03 300 99 V ollo! CH,CH,C+NHCHC NHCHC NHCHC+OH CH(CH,), CH,Ph CH₂CH₂SCH3 404.87 400 432.84 147➡ F 500 579.91 551.94 O mass-to-charge ratio m/z -M 131 M 600 M + 1 - H₂O 710.97 700 M + 1 = 729 M+1-H₂ 727.09 800