2D-O1-1030（2P-43） PDF
The Mechanism of On-chip Pulse-heating Ionization
The positive and negative ion generation pathway of pulse-heating ionization method was investigated by an on-chip ion source mass spectrometry. A uniformed thin film (approximately 30 nm) of sample was obtained due to the introduction of oxygen plasma treatment of ion source chip. A nearly ideal mass spectra, only singly charged parent ions with high signal-to-noise ratio, was obtained by only one pulse in both positive and negative detection mode. The protein sample of Cytochrome C was investigated with 2,5-dihydroxybenzoic acid as a matrix, whereas the inorganic sample of NaCl was demonstrated without matrix. By comparing the ion generation in both positive and negative mode, we propose a hypothesis based on electron and proton transfer to understand the mechanism of pulse-heating ionization. By only thermal energy supplying, the sample was evaporated and sublimated. At same time, the ion formed according to the electron and proton affinity.