Abstract: A mass spectrometry ionization method in which electrospray droplets or solid sample matrices are exposed to an ion beam thereby increasing the unbalanced charge of the analyte is provided. In another embodiment, a mass spectrometry ionization method in which ionization of the sample is achieved by directing an ion beam at a liquid or solid sample matrix containing analyte thereby ionizing and adding unbalanced charge to the analyte is provided.

Abstract: A mass spectrometry ionization method in which electrospray droplets or solid sample matrices are exposed to an ion beam thereby increasing the unbalanced charge of the analyte is provided. In another embodiment, a mass spectrometry ionization method in which ionization of the sample is achieved by directing an ion beam at a liquid or solid sample matrix containing analyte thereby ionizing and adding unbalanced charge to the analyte is provided.

Abstract: Mass tagging methods are provided that lead to mass spectrometer detection sensitivities and molecular discriminations that are improved over other methods. In particular the methods are useful for discriminating tagged molecules and fragments of molecules from chemical noise in the mass spectrum. These mass tagging methods are useful for oligomer sequencing, determining the relative abundances of molecules from different samples, and identifying individual molecules or chemical processing steps in combinatorial chemical libraries. The methods provided are useful for the simultaneous analysis of multiple molecules and reaction mixtures by mass spectrometric methods.

Abstract: Mass tagging methods are provided that lead to mass spectrometer detection sensitivities and molecular discriminations that are improved over other methods. In particular the methods are useful for discriminating tagged molecules and fragments of molecules from chemical noise in the mass spectrum. These mass tagging methods are useful for oligomer sequencing, determining the relative abundances of molecules from different samples, and identifying individual molecules or chemical processing steps in combinatorial chemical libraries. The methods provided are useful for the simultaneous analysis of multiple molecules and reaction mixtures by mass spectrometric methods.

Abstract: The present invention provides a method for protein sequencing using mass spectrometry. Also provided are protein labeling agents and labeled proteins for use in conjunction with the present method.