40
60
80
100
120
140
160
0
20
40
60
80
100
39
51
77
91
111
126
128
141
156
158
M+ (156)
M+2 / M+ = 0.33
one chlorine
-15 (loss of CH3)
m/z
relative intensity (% of base peak)
EI mass spectrum: discrete masses, so stems rather than a line