Electrospray ionization cone-voltage fragmentation

Electrospray is a soft-ionization method prodncing intact molecular species and structural information is not usually available. Electrospray sources are capable of producing structural information from cone-voltage fragmentation but these spectra are not always easily interpretable. Experimentally, the best solution is to use a mass spectrometer capable of MS-MS operation but this has not inconsequential financial implications. 

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. 

Crich and coworkers used a mass spectral method to investigate the influence of the oxazolidinone ring and its. -acety I counterpart on the activation of sialyl donors [22], They found that a minimum cone voltage of 78 V is required to cause fragmentation of the glycosyl phosphate 76 under electrospray ionization conditions (Fig. 5.6). The comparable oxazolidinone phosphate (77) did not undergo mass spectral fragmentation... 

Electrospray analysis can be performed in positive and negative ionization modes. The polarity of the ions to be analyzed is selected by the capillary voltage bias. A novel feature of the ESI mass spectrum is the formation of intact molecular ions of the analyte. Fragmentation, if desired, can be induced in the ion-transport region of the ESI source by increasing the sampling cone voltage. This process is known as in-source collision-induced dissociation (CID) or nozzle-skimmer (NS) dissociation. 

Energy-dependent electrospray ionization mass spectrometry (EDESI-MS) uses a map of cone voltage versus mjz upon which ion intensity is plotted, which provides a complete picture of the fragmentation pattern particularly suitable for the structural analysis of mixtures. " ... 

---