Particle-induced desorption methods

Particle induced desorption methods are commonly used to ionize low-volatility compounds. Cesium ion desorption (or cesium ion secondary ion mass spectrometry, SIMS) uses a primary beam of cesium ions to desorb and ionize a non-volatile sample. This technique has been used with FTMS to produce pseudomolecular ions of vitamin B12, ((812)2 + Cs - 2CN +, at m/z 2792 (24) and molecular ions of beta-cyclodextrin (m/z 1135) (92, 93). Detection limits of 10"13 mol for the peptide gramicidin S has been demonstrated using Cs+ SIMS with FTMS (25), and additional structural information was obtained using MS/MS processes. 

Fast atom bombardment FAB Particle induced desorption/ ionization Nonvolatile molecular ions Soft method Large molecules... 

The Cf-PD method has been largely supplanted by MALDI and ESI MS for the analysis of complex biological molecules because these methods are more efficient and widely applicable. The method has stimulated considerable interest in the field of particle-induced desorption and understanding of the mechanisms of the desorption/ionization process. Scanning tunnelling microscopy has been used to characterize the craters produced by fission... 

An electron or photon incident on a surface can induce an electroiuc excitation. When the electroiuc excitation decays, an ion or neutral particle can be emitted from the surface as a result of the excitation. Such processes are known as desorption induced by electroiuc transitions (DIET) [82]. The specific teclmiques are known as electron-stimulated desorption (ESD) and photon-stimulated desorption (PSD), depending on the method of excitation. 

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