HIGH MASS MOLECULAR IONS BY ELECTROHYDRODYNAMIC EMISSION

THE LONG-TERM OBJECTIVE OF THIS RESEARCH 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 IS TO DEMONSTRATE THE FEASIBILITY OF PRODUCING PROTEIN MOLECULAR IONS GENERATED BYION SOURCES THAT OPERATE ON THE PRINCIPLE OF ELECTROHYDRO- DYNAMIC (EHD) EMISSION. THIS ALTERNATE IONIZATION METHOD ISPROPOSED AS A SOFT IONIZATION METHOD; IT REDUCES 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 ADVANTAGES 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 SOLVENTFLOW, IONIC STRENGTH, AND SAMPLE CONCENTRATION. IT IS ANTICIPATED THAT CHARGED DROPLET SUPPRESSION AND PREFERRED ION EMISSION WILL BE DEMONSTRATED BY CONTROLLING THE SOLVENTTHROUGHPUT AND VISCOSITY BY COOLING THE EHD EMITTER. TOF MEASUREMENTS WILL BE USED TO MEASURE THE PARTICLE SIZE DISTRIBUTION OF THE ION BEAM.