B Common Fragment Ions

All fragments listed bear +1 charges. To be used in conjunction with Appendix C. Not all members of homologous and isomeric series are given. The list is meant to be suggestive rather than exhaustive. 

Appendix II of Hamming and Foster (1972). Table A-7 of McLafferty s (1993) interpretative book, and the high-resolution ion data of McLafferty (1982) are recommended as supplements. 

59 (CH3)2COH, CH2OC2Hs, C02CH3, NH2C(=0)CH2 + H, CH3OCHCH3, CHiCHCH2OH, c2 HjCHOH 

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Figure 12.3 Precursor-ion MS-MS acylcamitine profiles (common fragment ion m/z 85) with profiles from (a) a healthy newborn, (b) a newborn with MCAD deficiency (homozygous for A985G mutation), and (c) a newborn with MCAD deficiency (heterozygous for A985G mutation). Reprinted from [64] with permission. 1997, American Association for Clinical Chemistry.

B. Fragment Ions Common losses from the molecular ions include 90 and 105 Daltons. (See Figure 31.2 for the mass spectrum of the TMS derivative of cholesterol.)... 

When the molecular ion obtains too high energy during the electron impact, there are fragments that are generated in the ion source. The fragment ions A are commonly even electron ions EE (odd-electron fragments OE are also possible), while the rest of the molecule forms radicals B, which are not detected in the mass spectrometer ... 

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