HIGH MASS MOLECULAR IONS BY ELECTROHYDRODYNAMIC EMISSION

目的是开发用于质量分析的仪器

The objective is to develop instrumentation for the mass analysis of proteins and other biological macromolecules in the range of 10,000 to 100,000 AMU. The specific aim of Phase I studies is to demonstrate the feasibility of producing protein molecular ions generated by ion sources which operate on the principle of electrohydrodynamic (EHD) emission. This alternate ionization method is proposed as a "soft" ionization method - reducing the background in spectra introduced by fragment ion species. Glycerol solutions, as opposed to more volatile solvents, will be explored for high mass emission studies. The advantage of glycerol are low vapor pressure, permitting the application of higher electric fields before the onset of breakdown, and high viscosity at low temperatures. Both conditions are highly favorable for enhancing the emission of macromolecular ions. The macromolecular ion emission characteristics will be investigated with respect to solvent flow, ionic strength and sample concentration. It is anticipated that charged droplet suppression and preferred ion emission will be demonstrated by controlling the solvent throughput and viscosity by cooling the EHD emitter. TOF measurements will be used to measure the particle size distribution of the ion beam.