Mass Spectrometry of Small Molecules: Magnetic-Sector Instruments Mass spectrum of propane(C3Ha;MW=44) 100 80 -m/2=29 60 40 -m2=44 20 0 1020 40 60 80 100 120 140 m/2 Base peak Tallest peak Assigned intensity of 100% Base peak at m/z=29 in propane mass spectrum -Parent peak Unfragmented cation radical-molecular ion(M) Parent peak only 30%of base peak for propane Mass spectrum of propane (C3H8 ; MW = 44) ▪ Base peak ▪ Tallest peak ▪ Assigned intensity of 100% ▪ Base peak at m/z = 29 in propane mass spectrum ▪ Parent peak ▪ Unfragmented cation radical – molecular ion (M+ ) ▪ Parent peak only 30% of base peak for propane Mass Spectrometry of Small Molecules: Magnetic-Sector Instruments