Abstract: Compounds, compositions, methods for sequencing proteins and peptides, and methods for identifying proteins and peptides in a mixture, are disclosed. Compounds of formula A-B—C wherein A is a nucleophilic reactive group, B is a detectable moiety capable of being isotopically labeled, and C is a charge replacement group, are used to label the peptides at the N-terminus or the C-terminus. The tagged peptides can then be analyzed by mass spectroscopy.

Abstract: The invention provides methods of analyzing a sample. In general, the methods involve multi-dimensionally fractionating a sample to produce a set of sub-fractions, identifying a sub-fraction of interest by evaluating binding of a first portion of the sub-fractions to a binding agent; and analyzing the mass of analytes in a second portion of the sub-fraction of interest. Also provided is a system for performing the subject methods. The invention finds use in a variety of different medical, research and proteomics applications.

Abstract: The present invention provides methods for analyzing a peptide or peptides of interest in a protein sample using a combination of a relatively generic isotope tag with a decoupled selection process, allowing simplified customization of the application with a single reagent. These methods comprise providing a first and a second protein sample; labeling the first protein sample with a first Universal Peptide Isotope Tag (U-PIT) reagent and the second protein sample with a second U-PIT reagent; separating the peptide of interest from the combined first and second protein samples; and determining the relative amount of the first U-PIT reagent and the second U-PIT reagent bound to the peptide or peptides of interest. The U-PIT label of the present inventive methods has the following general formula A-B-C wherein A is a nucleophilic reactive group, B is a detectable moiety that can be isotopically labeled, and C is a charge replacement group.

Abstract: A method and apparatus are disclosed wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The invention provides reduced noise and increased signal sensitivity in both API electrospray and APCI operating modes.

Abstract: The present invention utilizes nucleic acid fusion proteins as secondary binding agents for detecting protein-protein interactions. The methods involve binding a target protein with a binding agent that is a protein nucleic acid fusion protein, wherein each binding agent has a unique nucleic acid sequence. Once binding of a fusion protein to a target protein occurs, the nucleic acid portion of the fusion protein is amplified and used to probe an array of nucleic acid molecules that are complementary to the amplified nucleic acid portions of the fusion proteins. Detection of the hybridized nucleic acid portion of the array identifies and quantifies the protein-protein interaction.

Abstract: A method and apparatus are disclosed wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The invention provides reduced noise and increased signal sensitivity in both API electrospray and APCI operating modes.

Abstract: A transfer capillary and interface are provided that allow samples from multiple fluid streams to be introduced into a single mass analyzer. The transfer capillary has two or more channels and is placed between a first chamber, in which ions from the multiple fluid streams are generated, and a second chamber that is in fluid communication with a mass analyzer. The interface includes ionizers that generate ionized sample from each fluid stream and that direct the ionized sample toward the channels of the transfer capillary. The transfer capillary includes a multiplex selector that allows ions to flow through a selected subset of channels and sequentially changes which of the channels are included in the subset of channels through which ions flow.

Abstract: A method and apparatus are disclosed wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The invention provides reduced noise and increased signal sensitivity in both API electrospray and APCI operating modes.

Abstract: The invention provides a microanalytical device for analyzing a fluid sample containing at least one analyte molecule. The device is constructed from a substrate and a cover plate each having a substantially planar surface and a microchannel formed therein. The cover plate is placed over the substrate such that the cover plate microchannel is arranged in opposing relationship with the substrate microchannel. A membrane is interposed between the substrate and the cover and has at least one pore sized to allow passage of the analyte molecule from the substrate microchannel to the cover plate microchannel. An analyte altering moiety is attached to an interior surface of the pore and is capable of chemically altering the analyte molecule. Also disclosed are a method for chemically altering and transporting an analyte molecule in a fluid and a method for identifying a plurality of biomolecules.

Abstract: A method and apparatus are disclosed wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The invention provides reduced noise and increased signal sensitivity in both API electrospray and APCI operating modes.

Abstract: A transfer capillary and interface are provided that allow samples from multiple fluid streams to be introduced into a single mass analyzer. The transfer capillary has two or more channels and is placed between a first chamber, in which ions from the multiple fluid streams are generated, and a second chamber that is in fluid communication with a mass analyzer. The interface includes ionizers that generate ionized sample from each fluid stream and that direct the ionized sample toward the channels of the transfer capillary. The transfer capillary includes a multiplex selector that allows ions to flow through a selected subset of channels and sequentially changes which of the channels are included in the subset of channels through which ions flow.

Abstract: A method and apparatus are disclosed wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The invention provides reduced noise and increased signal sensitivity in both APT electrospray and APCI operating modes.

Abstract: A method is provided for the separation of nucleic acid samples. The method includes: providing a test mixture of a plurality of nucleic acid samples, wherein each sample is labeled with a spectrally detectable tag; applying the test mixture to a reversed phase solid support; eluting the mixture under partially denaturing conditions; and detecting spectrally resolved signals produced by the nucleic acid samples labeled with the detectable tags.

Abstract: A method is provided for the separation of nucleic acid samples. The method includes: providing a test mixture of a plurality of nucleic acid samples, wherein each sample is labeled with a spectrally detectable tag; applying the test mixture to a reversed phase solid support; eluting the mixture under partially denaturing conditions; and detecting spectrally resolved signals produced by the nucleic acid samples labeled with the detectable tags.

Abstract: A method and apparatus are disclosed wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The invention provides reduced noise and increased signal sensitivity in both APT electrospray and APCI operating modes.

Abstract: A method and apparatus are disclosed wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The invention provides reduced noise and increased signal sensitivity in both API electrospray and APCI operating modes.

Abstract: Apparatus for in-line flow-through sample treatment includes a sample channel that has a sample inlet and a sample outlet and is defined in part by inner surfaces of walls of a solid material and in part by an inner surface of a first membrane, and a first flushing channel that has an inlet port and an outlet port and is defined in part by inner surfaces of walls of a solid material and in part by an outer surface of the first membrane. An electric field is applied across the first membrane in liquids carried within the sample channel and the first flushing channel. The analytical stream flows from an upstream liquid analysis device, such as a liquid chromatographic column, into the sample inlet and through the sample channel and out from the sample outlet, and a flushing liquid flows into the inlet port and through the flushing channel and out from the outlet port. Charged particles (such as ions of inorganic salts) in the analytical stream move in a direction generally away from or toward the membrane.

Abstract: A method and apparatus wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The invention provides reduced noise and increased signal sensitivity in both API electrospray and APCI operating modes.

Abstract: A method apparatus wherein a plurality of electric fields and of orthogonal spray configurations of vaporized analyte are so combined as to enhance the efficiency of analyte detection and mass analysis. The method and apparatus provides reduced noise and increased signal sensitivity in both API electrospray and APCI operating modes.

Abstract: .[.The invention teaches the uses of a plurality of electric fields and of orthogonal spray configurations of vaporized analyte which combine so as to operate to enhance the efficiency of analyte detection and mass analysis with a mass spectrometer by reducing vapor in the vacuum system and concomitant noise. Several embodiments of the invention are described for purposes of illustration..]. .Iadd.The invention relates to a method and apparatus for improving signal relative to noise without loss of ion collection efficiency in electrospray mass spectrometry, including liquid chromatography/mass spectrometry..Iaddend.