Cone-voltage fragmentation applications

In addition to the formation of these ions of direct analytical utility, APCI leads to the formation of ion clusters involving solvent molecules. Since these tend to make interpretation more difficult, they need to be removed and this may be accomplished either by the use of a curtain gas or by cone-voltage fragmentation (see Section 4.7.4 above) which is also applicable to APCI. 

Cone-voltage fragmentation Fragmentation of ions, commonly produced by APCl or electrospray ionization, effected by the application of a voltage within the source of the mass spectrometer. 

The ionization techniques most widely used for LC-MS, however, are termed soft ionization in that they produce primarily molecular species with little fragmentation. It is unlikely that the molecular weight alone will allow a structural assignment to be made and it is therefore desirable to be able to generate structural information from such techniques. There are two ways in which this may be done, one of which, the so-called cone-voltage or in-source fragmentation, is associated specifically with the ionization techniques of electiospray and APCl and is discussed later in Section 4.7.4. The other, termed mass spectrometry-mass spectrometry (MS-MS) or tandem mass spectrometry, is applicable to all forms of ionization, provided that appropriate hardware is available, and is described here. 

Harris, J. Wilkins, J. The Application of HPLC-Cone Voltage Assisted Fragmentation Electrospray Mass Spectrometry to the Determination of Veterinary Drug Residues. In Residues of Veterinary Drugs in Food, Proceedings of the Euroresidue III Conference, Veldhoven, May 6-8, 1996 Haagsma, N., Ruiter, A., Eds. Fac. Vet. Med., Univ. Utrecht The Netherlands, 1996. 

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