Described are dual mass-spectrometry-cleavable cross-linkers that can be cleaved selectively using two differential tandem mass-spectrometric techniques such as collision induced dissociation (CID) or electron transfer dissociation (ETD), i.e., a dual cleavable crosslinking technology (DUCCT) cross-linker. When used to cross-link a macromolecule, such as a peptide, MS/MS fragmentation produces two signature complementary mass spectra of same cross-linked peptides, the analysis of which gives rise to high confidence in characterizing the structures of the cross-linked macromolecules as well as sites of interactions. Also described, are methods of making and using DUCCT cross-linkers.

Lysosomal acid lipase (LAL) substrates, assays for lysosomal acid lipase using the substrates, and methods for diagnosing diseases and conditions attributable to lysosomal acid lipase deficiency.

The disclosure features systems and methods that include: exposing a biological sample to an ion beam that is incident on the sample at a first angle to a plane of the sample by translating a position of the ion beam on the sample in a first direction relative to a projection of a direction of incidence of the ion beam on the sample; after each translation of the ion beam in the first direction, adjusting a focal length of an ion source that generates the ion beam; and measuring and analyzing secondary ions generated from the sample by the ion beam after adjustment of the focal length to determine mass spectral information for the sample, where the sample is labeled with one or more mass tags and the mass spectral information includes populations of the mass tags at locations of the sample.

A system, method, diagnostic and container delivery system for manipulating a target, by manipulating with the quantum coherence of the target. The method includes identifying intrinsic parameters of the target and determining target-tuned design factors based at least partially on the intrinsic parameters. Target-tuned electrons and fields are generated based in part on the target-tuned design factor. The target-tuned electrons and fields are defined by discrete quantized energy levels. The method may include preparing a container to carry the unquantized target-tuned electrons, the container being composed of superconductor quantum dots. The unquantized target-tuned electrons are transferred to the container to form target-tuned artificial atoms having quantized target-tuned electrons, which may be delivered to the target as a manipulating agent. Alternatively, the unquantized target-tuned electrons may be delivered directly to the subject.

Provided herein are methods of measuring glycogen and methods of diagnosing a disease. One method of measuring includes separating sugar monomers and sugar phosphates using gas-chromatography, and analyzing the monomers and phosphates using mass spectrometry. Another method of measuring includes adding an isoamylase to a sample, the isoamylase cleaving glucose chains from glycogen; applying a matrix-assisted laser desorption ionization (MALDI) ionization matrix to the sample; and analyzing the samples using matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). The method of diagnosing a disease includes determining an amount and location of glycogen accumulation in a subject; and diagnosing a disease when over-accumulation of glycogen is determined.

Disclosed is a method for measuring an Aβ peptide, comprising: mixing a blood sample comprising an Aβ peptide and an antibody that specifically binds to the Aβ peptide to form a complex of the Aβ peptide and the antibody; releasing the AP peptide from the complex with a basic solution comprising an organic solvent; and measuring the released Aβ peptide by mass spectrometry.

Disclosed is a method for measuring an Aβ peptide in a blood sample in vitro, comprising: measuring the Aβ peptide by an immunoassay using an antibody set comprising a capture antibody and a detection antibody that specifically bind to the Aβ peptide, wherein the capture antibody is an antibody that binds to an epitope comprising an N-terminal residue of the Aβ peptide, the detection antibody is an antibody that binds to an epitope different from the epitope to which the capture antibody binds, and the Aβ peptide is at least one selected from the group consisting of Aβ40 or Aβ42.

This document relates to methods for identifying one or more immunoglobulin free light chains in a sample using mass spectrometry. For example, this document relates to a method for identifying one or more immunoglobulin free light chains in a sample that includes (a) providing a sample; (b) subjecting the sample to a mass spectrometry technique to obtain a mass spectrum of the sample; and (c) identifying the presence of the one or more immunoglobulin free light chains.

Provided are a novel internal standard useful in the measurement of androgens, a method capable of measuring the androgen in a highly selective and highly sensitive (accurate) manner using liquid chromatography mass spectrometry with simplified pretreatments, and a method for diagnosis of a disease using the androgen measurement method. The novel stable isotope-labeled compound is synthesized by performing reduction reaction in a specific solvent. An androgen is measured using this novel stable isotope-labeled compound as an IS.

The present invention provides a method for detecting a monoclonal antibody in a sample, the method comprising: (a) a step of capturing and immobilizing, in pores of a porous body, the monoclonal antibody in the sample; (b) a step of performing selective protease digestion of the monoclonal antibody for 30 min or longer by contacting the porous body having the monoclonal antibody immobilized thereon with nanoparticles having a protease immobilized thereon; and (c) a step of detecting a peptide fragment obtained by the selective protease digestion, using liquid chromatography mass spectrometry (LC-MS), wherein step (b) is carried out under stirring condition for 10 sec to 5 min in the initial reaction stage, and then under static condition. According to the present invention, the detection method of a monoclonal antibody using mass spectrometry is simplified and can be applicable to multisample analysis.