Abstract: The present invention provides new methods for producing substantially continuous, homogeneous layers of MALDI matrix materials deposited on MALDI targets and substantially free of voids and large crystals. The methods involve the deposition of MALDI matrix materials in a nebulized spray which is enveloped in a sheath of non-reactive gas which confines and entrains the spray and aids in the evaporation of the solvent such that substantial, if not complete, solvent evaporation occurs before the matrix material is deposited on the target surface. The invention further provides such matrix layers and pre-formed matrix-bearing targets for use in MALDI mass spectrometry.

Abstract: An improved method for the mass spectrometric determination of the molecular weight of a highly polyionic analyte is provided. The method employs reagents which are highly polyionic but which are of opposite charge to the analytes. The reagents and analytes form a non-covalent complex which is more easily ionized during mass spectrometry and decreases fragmentation of the analyte. Highly polyionic reagents are also provided. The reagents include a multiplicity of highly ionic groups covalently attached along a flexible molecular backbone.

Abstract: Effluent from a liquid chromatograph is deposited onto a moving flat sThe Government has rights in this invention pursuant to Grant Number 5-POl-ES01640-08 awarded by the National Institutes of Health.

Abstract: Effluent from a liquid chromatograph (LC) is deposited onto a deposition medium having a deposition surface inert to the LC effluent elevated above and parallel to a planar IR reflective front surface, preferably driven so as to define a continuous sample track in a generally circular, spiral or raster pattern. In the preferred embodiment, the deposition medium is a plate of germanium inert to aqueous and nonaqueous solvents, thicker than the longester IR wavelength of interest and having an undercoating of aluminum. Effluent is preferably deposited in a spiral pattern on the deposition medium in the form of a rotating disk. After collection, the reflection spectra can be interrogated by Fourier transform IR spectroscopy. The same collection technique can be used to collect and mount samples for mass spectrometry. To promote solvent evaporation, the effluent discharge is enveloped by a stream of heated nitrogen, particularly beneficial for reversed phase chromatography.