Development Of Mass Spectrometry Instrumentation For The Analysis Of Metal Clusters

Metal clusters initially received attention due to their unique metallic bonds.The research of metal clusters currently tends to be highly nucleated and functionalized.The size of highly nucleated metal cluster molecules can reach nanometer level so they are nano molecules of definite composition and structure,which provide an important cut-in point for the further study of nano materials.Besides,metal clusters as a new type of functional materials have also showed unique properties in medicine,catalysis,optics,electronics,magnetics,etc.Traditional analytical methods such as x-ray single crystal diffraction have defects in the test accuracy of metal clusters and have difficulty in the real-time analysis to study dynamic processes of cluster reactions.Mass spectrometry(MS)can distinguish ions by their mass-to-charge ratios precisely and monitor cluster reactions in real time,so it's an effective supplement to traditional analytical methods of metal clusters.The chemical bonding of metal clusters is complicated.Moreover,metal clusters provide abundant mass spectra peaks with a wide range of mass.Our study is to design and develop mass spectrometers based on analytical characteristics of metal clusters as future theoretical and practical references for subsequent instrumental development related.Time-of-flight(TOF)mass analyzer provides a wide range of mass detected with high resolution and good sensitivity,which is suitable for the analysis of metal clusters.A two-stage orthogonal acceleration TOF mass analyzer with ion reflection was designed and built.It was then equipped with an electron impact ion source(EI)to form an EI-TOFMS.Trajectories of ions in EI-TOFMS were simulated by ion optic software to obtain optimum instrument parameters and to analyze influences of instrument parameters on the ion motion and instrument indicators.EI-TOFMS was debugged,its RFWHM of 7175 and detection limit of 3.9ppb were obtained which confirmed the TOF mass analyzer worked properly.Nanoelectrospray ion source(nanoESI)is soft producing multi-charged ions with high ionization efficiency,which is suitable to ionize metal clusters.A piece of nanoESI apparatus and its necessary ion transport system were designed and built.They were then equipped with the TOF mass analyzer above to form a nanoESI-TOFMS based on the analysis of metal clusters.Trajectories of ions in the ion transport system of nanoESI-TOFMS were simulated by ion optic software to obtain optimum instrument parameters and to analyze influences of instrument parameters on the ion motion and transmission efficiency of ions.