1. Aromatics No branching = strong M+. Often see M++.
m/z 77, 51 = phenyl (monosubst benzene)
Most prominent peaks are due to beta cleavage of branches to benzylic (really tropylium.)

3. Alcohols Weak M+. Often nonexistent for 2º, 3º.
M-18 (water) (rearrangement using δH?)
M-33 (water + methyl) (1º)
β cleave largest branch to oxonium

5. Ethers Homologous series is +2 (31, 45, 59….) β cleave to oxonium
C-O cleavage to R+
Acetals β cleave to very stable oxonium with 2 res structures  no M+ seen

7. Carbonyl Compounds α cleave to acylium ion (vs 43, 57, 71 peak)
McClafferty rearrangement if γ H is present (neutral or pos alkene fragment)
M-28, M-42, M-56
28, 42, 56…