Abstract: The invention provides for the identification of target proteins in a sample based upon multiple sets of peptide fragment mass data obtained from the sample via gas phase ion spectroscopy. The sets of data are the product of analytical conditions that typically differ for each set such that cumulatively the data sets have higher information content than any individual set, thus enhancing the confidence level for accurate target protein identification. Probes, systems, and kits are additionally provided.

Abstract: The invention provides methods of monitoring the production of a target polypeptide by generating surface enhanced laser desorption/ionization mass spectral profiles of samples taken from multiple cell culture batches or of samples taken at different times from a given batch. The invention additionally provides methods for monitoring the purification of a target polypeptide from a mixture by generating surface enhanced laser desorption/ionization mass spectral profiles of samples taken at various times during a purification process. In addition, the invention relates to methods of identifying conditions that can be used in increasing the scale of a given purification process.

Abstract: This invention provides a method for analyzing analytes in a sample by mass spectrometry. The method involves pre-fractionating the sample by size exclusion and/or ion exchange chromatography, applying the sample to an adsorbent attached to the surface of a mass spectrometry probe, and allowing both specific and non-specific adsorption of analytes the adsorbent (e.g., by allowing the sample to dry without washing to remove unbound sample). Then an energy absorbing material is added to the dried sample, and the sample is analyzed by laser desorption/ionization mass spectrometry.