An analysis method is provided, wherein a measurement sample containing a diamine and an acid dianhydride can be obtained without a separate methyl derivatization process. The analysis method includes pretreating a polyimide film including the polyimide which is a poorly soluble polymer with DMAc after hydrolysis, and determining an amount of monomers contained in the polyimide film.

Disclosed herein are embodiments of methods for oligonucleotide analysis using a novel solid-phase extraction and hydrophilic-interaction liquid chromatography. The unique polar-based retention methods provided herein provide a high-recovery extraction. The methods improve assay reliability and reproducibility and reach picomolar sensitivity with the demonstrably beneficial accurate mass platform. Also disclosed herein are systems and computer program products for performing these methods.

A real-time online analysis device for substance pyrolysis, including: a pyrolyzing system (1), a capturing system (2), a testing system (3) and a controlling system (4) is disclosed. The pyrolyzing system (1), the capturing system (2) and the testing system (3) are connected with the controlling system (4). The capturing system (2) has a cooling cavity (22) and a heating cavity (23) inside. The temperature of the cooling cavity (22) ranges from room temperature to −200° C., and the temperature of the heating cavity (23) ranges from room temperature to 1000° C. A method for real-time online analysis of substance pyrolysis using the device is also disclosed. The present device can provide real-time online pyrolysis, capturing, separation and analysis of substances at a plurality of temperature points or ranges.

The disclosed system and method improve measurement of trace volatile chemicals, such as by Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GCMS). A first trapping system can include a plurality of capillary columns in series and a focusing column fluidly coupled to a first detector. The first trapping system can retain and separate compounds in a sample, including C3 hydrocarbons and compounds heavier than C3 hydrocarbons (e.g., up to C12 hydrocarbons, or compounds having a boiling point around 250° C.), and can transfer the compounds from the focusing column to the first detector. A second trapping system can receive compounds that the first trapping system does not retain, and can include a packed trap and two columns. The second trapping system can remove water from the sample and can separate and detect compounds including C2 hydrocarbons and Formaldehyde.

Disclosed herein are a group of gastric cancer VOC markers in saliva and an application thereof in the preparation of a diagnostic reagent of gastric cancer. The markers are a combination of compounds selected from the group consisting of acetaldehyde, 2-methylbutyraldehyde, isopropanol, hexanal, n-butanol, cineole, nonanal, menthone, 2-ethylhexanol, menthol, anethole and dodecanol. The diagnostic reagent is used for detecting the contents of the marker in a saliva sample of a subject to perform the diagnosis of gastric cancer.

Disclosed herein are a group of gastric cancer VOC markers in saliva and an application thereof in the preparation of a diagnostic reagent of gastric cancer. The markers are a combination of compounds selected from the group consisting of acetaldehyde, 2-methylbutyraldehyde, isopropanol, hexanal, n-butanol, cineole, nonanal, menthone, 2-ethylhexanol, menthol, anethole and dodecanol. The diagnostic reagent is used for detecting the contents of the marker in a saliva sample of a subject to perform the diagnosis of gastric cancer.

An analysis method includes: performing liquid chromatography using a mobile phase including an adsorption prevention agent for preventing adsorption of a sample including a compound having a phosphate group to metal; and performing mass spectrometry on an eluate of the liquid chromatography. The adsorption prevention agent includes an oxalic acid or a salt of the oxalic acid.

The present invention provides a snake venom thrombin marker peptide of Agkistrodon Halys Pallas and an application of the snake venom thrombin-like enzyme in identifying species of Hemocoagulase for Injection. The application includes the following steps of: dissolving a to-be-detected sample and a reference substance of the marker peptide respectively to prepare a test solution and a reference solution, and conducting alkylation reduction on the test solution and the reference solution with dithiothreitol and iodoacetamide; after diluting products with an ammonium bicarbonate solution, adding enzyme for hydrolysis; and after enzymolysis is finished, conducting centrifugation at a high speed, and injecting a supernatan into a liquid chromatography-mass spectrometer for analysis. This method is simple, convenient and rapid, is strong in specificity, fills the gap in identifying the source of species of the snake venom thrombin-like enzyme of Agkistrodon Halys Pallas and improves the quality control level.

The measurement of glutaraldehyde-based biocides in seawater without the use of a derivatization agent. The measurement of glutaraldehyde-based biocides in seawater may be performed without additional components to reduce background interferences. The concentration of a glutaraldehyde-based biocides in a seawater sample is determined using reversed phase liquid chromatography and a gradient mobile phase of acetonitrile and deionized water. Systems for determining the concentration of glutaraldehyde-based biocide in a seawater injection system are also provided.

The present invention generally pertains to methods of characterizing charge variants of a protein of interest. In particular, the present invention pertains to the use of desalting size exclusion chromatography-reduced peptide mapping mass spectrometry to identify charge variants separated by capillary isoelectric focusing.