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Time-of-flight Secondary Ion Mass Spectrometry using MeV heavy ions (MeV TOF-SIMS) is a newly developed mass spectrometry technique used for molecular identification and imaging of various organic materials. In MeV TOF-SIMS, MeV ions interact with the surface layers of the sample mostly through the electron scattering, causing desorption of intact molecular ions and making the determination of sample molecular composition much easier. Several orders of magnitude larger yields, as well as less fragmentation, are expected for larger molecular masses when MeV ions are used for the excitation, which is especially important for imaging of organic samples with a micrometer lateral resolution. Due to the technique potential to analyse high-masses with high-sensitivity, and fact that is surface sensitive, MeV TOF-SIMS can be employed to analyse organic samples such as fingerprints, paints, inks, tissue, body fluids, etc. Since the MeV TOF-SIMS is done with MeV ions, standardly used for the Ion Beam Analysis (IBA), it is a complimentary technique to the other IBA techniques such as PIXE, EBS, ERDA providing information about molecular composition of the analysed samples. Recent results on the application of MeV TOF-SIMS in the analysis of biological, forensic and cultural heritage samples will be presented. MeV TOF-SIMS was successfully applied for the 2D imaging of the various lipids in the mouse liver and brain tissue and investigation of chemical changes in the body fluids (serum and urine) of the healthy and diabetic mice. Secondly, MeV TOF-SIMS in combination with Particle Induced X-ray Emission (PIXE) was applied to determine deposition order of the different writing tools for forensic document examination. In addition, MeV TOF-SIMS was demonstrated to be successful for the identification of synthetic organic pigments and binders in contemporary art objects. |
