A method is disclosed comprising obtaining physical or other non-mass spectrometric data from one or more regions of a target using a probe. The physical or other non-mass spectrometric data may be used to determine one or more regions of interest of the target. An ambient ionisation ion source may then used to generate an aerosol, smoke or vapour from one or more regions of the target.

The present disclosure relates to methods of identifying RNA-edited peptides. In an aspect, the identified peptides are capable of eliciting immune responses in individuals or patients. The present disclosure further relates to RNA-edited peptide sequences identified by methods described herein. In a further aspect, the disclosure provides for methods of treating cancer in individuals or patients by utilizing the methodology described herein.

A method for preparing an analytical sample for analysis of a glycan that includes a lactone structure and is contained in a sample, includes: performing a first amidation reaction that amidates a sialic acid including the lactone structure through addition of a first amidation reaction solution to the sample, the first amidation reaction solution containing ammonia, an amine, or a salt thereof as a first nucleophilic agent that is reacted with the sialic acid including the lactone structure; and performing a second reaction that modifies at least a part of sialic acids not amidated in the first amidation reaction through a method different from permethylation.

Compositions and methods for sample preparation and mass spectrometric analysis of peptide samples obtained from biological samples are provided. The compositions and methods include a tandem column system in which a trap column is in fluid contact with an analytical column such as, for example, a HPLC column. As analytes are eluted from the analytical column, they can be passed to a detector (e.g., a mass spectrometer) for peptide analysis.

Systems and methods for automated sample preparation and processing of protein corona are described herein, as well as its application in the discovery of advanced diagnostic tools as well as therapeutic agents.

A system includes an optical measurement unit that measures an optical property of a whole blood sample deposited on a surface of a substrate, an ion source that causes ions derived from the whole blood sample, including ions formed from an analyte of interest present in the whole blood sample, to be emitted from the substrate, a mass analyzer that receives the ions emitted from the substrate and measures an abundance of at least one ion species corresponding to the analyte of interest, and at least one computing device that determines, based on the measured optical property, a hematocrit of the whole blood sample, and determines, based on the determined hematocrit of the whole blood sample and the measured abundance of the at least one ion species, a concentration of the analyte of interest per unit volume of blood plasma.

The present invention is directed to methods for using particles (e.g, microparticulate, nanoparticulate; magnetic, non-magnetic) comprising surfaces comprising capture moieties as described herein, to remove an interference as described herein, or enrich biomarkers, prior to a diagnostic test.

The invention relates generally to peptide biomarkers with specific ionization characteristics to directly quantify one or more transgenic target proteins in biological samples, including transgenic plant samples, by liquid chromatography coupled tandem mass spectrometry multiple reaction monitoring (MRM). The peptide biomarkers in combination with MRM-based methods may be used to quantify a single transgenic target protein or multiple transgenic target proteins within a stacked transgenic crop, such as maize, utilizing selected peptide biomarkers either alone or in combination. The present disclosure allows for broad based, reliable quantitation in different biological matrices, including plant matrices. The peptide biomarkers of the invention can further be used as trait biomarkers to support identification and/or selection of specific transgenic Events. Also provided are different peptide biomarker combinations that can be used to perform the methods of the invention.

A method for determining an amino acid sequence of a polypeptide, including comprising: contacting a first sample containing the polypeptide with a first protease(e.g., Trypsin) to produce a first set of digested peptide fragments; fragmenting the first set of digested peptide fragments to produce a first set of fragmented peptide ions; determining masses of the first set of fragmented peptide ions; contacting a second sample containing the polypeptide with a second protease (e.g., Tryp-N); fragmenting the second set of digested peptide fragments to produce a second set of fragmented peptide ions; selecting pairs of peptide ions from the first and the second set of fragmented peptide ions that differ in mass by a mass of an arginine amino acid residue or a lysine amino acid residue; assigning an ion type (either N-terminal peptide ion or C-terminal peptide ion) to the selected pairs of the peptide ions from two sets of fragmented peptide ions;selecting a mass ladder of the same-type peptide ions in either set of fragmented peptide ions with incremental mass by the mass of amino acid residue(s), and assembling the identified amino acid residues from the mass ladder to determine the amino acid sequence of the polypeptide of interest.

A method for the identification and localization of small molecule species in a histologic thin tissue section comprises the steps of: a) acquiring a mass/mobility image of the tissue section and generating a mass/mobility map of the small molecule species of interest for each pixel of the image; b) providing a second sample of the same tissue and extracting the small molecules of interest, separating them, and acquiring mass and ion mobility spectra from the separated small molecules; c) identifying the small molecules of interest using corresponding reference databases; and d) assigning identified small molecules to entries in the mass/mobility maps of the first tissue section by comparison of ion masses and mobilities of the identified species to those of the second thin tissue section.