The long term objective of this application is to develop instrumentation for the mass analysis of biological macromolecules in the mass range 10,000 to 100,000 amu. The specific aim of Phase II is to demonstrate the emission and detection of biological sample ions to MW 11,500 using an electrohydrodynamic (EHD) ionization source mounted on a JEOL double focusing mass spectrometer. The methodology for meeting this goal includes a continuation of Phase I studies which examined sample ion desolvation, solvent chemistry and methods for handling small and valuable samples. Enhancement of the intensity of molecular ion emission by cooling the EHD ion source and improved ion transmission by adding beam optics will be pursued. Particular attention will be focused on the demonstrated capability of the EHD ionization process to produce doubly and triply charged ions for extending the detectable mass range of sample ions. Aqueous or high volatility solvents will be explored and characterized for their potential of achieving complete sample desolvation and reducing the complexities in high mass ion spectra observed with glycerol. The commercial application of EHD ion source development, coupled to a matching mass analyzer, will impact the biotechnology field by introducing a new, more accurate method of high mass molecular weight determinations for proteins and other macromolecular biological compounds.