Cluster-induced desorption/ionization mass spectrometry as a versatile tool for the analysis of complex molecules and their reactions on surfaces

Desorption/Ionization Induced by Neutral SO 2 Clusters (DINeC) is employed as a very soft and efficient desorption/ionization source for mass spectrometry of molecules and their reactions on surfaces. The matrix-free desorption method is based on cluster-surface impact of SO 2 clusters at low cluster energy. As a result, fragmentation-free spectra from surfaces composed of or covered with complex molecules such as peptides and proteins are observed. Molecules at a surface coverage as low as 0.1 monolayers were detected; surface reactions such as H/D exchange or thermal decomposition were observed in real-time and the kinetics of the reactions could be deduced.