Fragments Lost

This list is suggestive rather than comprehensive. It should be recommended as supplements. All of these fragments are lost used in conjunction with Appendix B. Table 5-19 of Hamming as neutral species, and Foster (1972) and Table A-5 of McLafferty (1993) are 

Molecular Ion Minus Fragment Lost (Inference Structure) 

16 O (ArN02, amine oxides, sulfoxides) -NH2 (carboxamides, sulfonamides) 

43 C3H7-(propyl ketones, ArCH2—C3H7), CH3C-(methyl ketones, CH3CG, where G = various functional groups), CH2=CH—O-, (CH3- and CH2=CH2), HCNO 

45 CH3CHOH, CH3CH20 (ethyl esters), C02H, CH3CH2NH2 

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For linear alkanes, the initial fragment lost is an ethyl group (never a methyl group), followed by propyl, butyl, and so on. An intense peak at mass 43 suggests a chain longer than butane. 

A molecular ion is seen in the electron impact mass spectrum of compound (6) but the base peak is that resulting from the loss of nitrogen [M — 28] <91AG(E)1476>. The electron impact mass spectra of sydnones show the loss of NO and CO, either consecutively or simultaneously <84CHEC-I(6)365). A study of the Cl mass spectra of protonated sydnones, with methane as the reagent gas, shows that HNO and CO are the fragments lost <89H(29)185>. The electron impact mass spectrum of compound (19) shows an intense molecular ion which loses NO and then HCN <85JCS(Pi)2439>. 

Indicate the type(s) of cleavage and the fragments lost which gives rise to the major ions in the spectrum of butan-2-ol shown in Figure 9.8. 

Loss amu Radicals/neutral fragments lost Interpretation... 

Often the neutral fragment lost is of as much structural significance as the ion formed. Thus it should be possible to construct a similar tabulation using the mass of the difference between the abundant ion... 

The formulae for the neutral fragments lost in transitions of metastable ions and confirmed by high resolution MS data build up into a scheme (Figure 3). Most metastable ions appeared within 0.1 of the calculated value, but two, at m/z. 

Common Fragmentation Patterns of Families of Organic Compounds Common Fragments Lost... 

Mass Lost Fragment Lost Mass Lost Fragment Lost... 

Neutral loss fragment lost as a neutral species. 

Some Common Fragments Lost in Mass Spectra... 

There are two types of mass spectroscopy rules that concern (1) common fragment ions and (2) common fragments lost. Both of these rules can be defined in the same type of data structure. The components of the data structure are ... 

Comparison of fragments lost from cyclopeptides a and b observed in the FD/B/fi/CAD spectra [223]... 

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