Abstract: The present disclosure provides a method for calibrating a difference in signal intensity ratio between machines in mass spectrometry.

Abstract: A calibrant for use in correction of machine difference of mass spectrometers and a method for producing the calibrant are provided. A calibrant for use in a mass spectrometer, the calibrant comprising not less than two calibration substances, wherein a ratio of, relative to a concentration of one calibration substance of the not less than two calibration substances, a concentration of another calibration substance of the not less than two calibration substances is a predetermined value, and a method for producing the calibrant.

Abstract: A mass spectrometry method includes detecting, in a first mass spectrometry of a sample containing a glycan having a plurality of sialic acids each modified differently, a plurality of oxonium ions derived from each of the plurality of sialic acids, and calculating relative values of intensities of the plurality of oxonium ions based on data obtained by the detection.

Abstract: A method for preparing an analysis sample includes providing a sample containing a glycan, and performing an amidation reaction through contacting the sample with an amidation reaction solution having a pH of 7.7 or more, the amidation reaction solution containing at least one first compound which is to be reacted with a lactone included in the glycan, and which is selected from the group consisting of ammonia to be reacted with a lactone included in the glycan, primary amines having one or no carbon atom directly linked to a carbon atom linked to an amino group, hydrazine, hydrazine derivatives, hydroxylamine, and salts thereof, and alkalinizing agents to amidate the lactone, wherein when the alkalinizing agent is an amine, the alkalinizing agent is at least one amine selected from the group consisting of branched primary amines in which two or more carbon atoms are directly linked to a carbon atom linked to an amino group, secondary amines, and tertiary amines.

Abstract: In a glycan structure analyzer according to one mode, a plurality of tabs for setting analysis conditions includes a dedicated tab for the setting of the conditions concerning a chemical modification specific to the linkage type of sialic acids, allowing a user to select major chemical modification agents. When one of those agents is selected, the mass change for each linkage type is automatically set. When using a chemical modification other than the preset ones, the user can input a numerical value of the amount of mass change for each linkage type. In an analysis, theoretical m/z values of a plurality of glycan structure candidates having different m/z values depending on the linkage type corresponding to one chemical modification are simultaneously compared with the m/z values of measured ion peaks.

Abstract: A method for preparing an analysis sample from a sample containing a glycan, includes: performing esterification reaction that subjects at least a part of a sialic acid included in the glycan to esterification other than lactonization; and performing amidation reaction that converts an esterified form of a sialic acid modified through the esterification into an amidated form through contacting the sample with an amidation reaction solution containing at least one compound selected from the group consisting of ammonia, amines, hydrazine, hydrazine derivatives, and hydroxyamine, and salts thereof to be reacted with the sialic acid modified through the esterification.

Abstract: A method for preparing an analytical sample for analysis of a glycan contained in a sample includes: performing an amidation reaction that amidates a lactone structure included in the glycan through contacting the sample with a reaction solution that is basic; adding an acidic solution to the reaction solution after the reaction solution is subjected to the amidation reaction; and purifying the sample contained in the reaction solution after the acidic solution is added to the reaction solution by using a carrier for hydrophilic interaction chromatography.

Abstract: 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.

Abstract: A method for preparing an analytical sample for analyzing a glycan contained in a sample includes: performing a first reaction so that when sialic acid is linked to the glycan, sialic acid of a first linkage type is lactonized and modification different from lactonization is performed on sialic acid of a second linkage type different from the first linkage type; performing a second reaction to ring-open a lactone formed in the first reaction; and performing the first reaction again.

Abstract: Glycans having a branched structure are labeled with a labeling agent, such as 2-aminobenzoic acid, having one site that is easily negatively charged. At this time, reduction which is usually performed in labeling by reduction amination is not performed. A sample for mass spectrometry containing the labeled form of glycans thus obtained is prepared, and is subjected to MS/MS analysis in negative ion mode. In the MS/MS spectra obtained by the MS/MS analysis, peaks of E ions, D ions and the like which reflect the branched structure clearly appear. As a result, structural analysis of an entirety of the glycan including the branched structure can be easily performed.

Abstract: A method for preparing a sample comprising a glycan includes: performing a lactonization reaction in which at least a part of sialic acids included in the glycan is lactonized; and performing an amidation reaction in which lactones of lactonized sialic acids are amidated through addition of an amidation reaction solution to the sample, the amidation reaction solution comprising at least one selected from the group consisting of ammonia, an amine, and a salt thereof that is reacted with the lactonized sialic acids.

Abstract: Provided is a method for efficiently analyzing the structure of a sialylated glycan, including the linkage type of a sialic acid linked to a terminal of the glycan. After the sialic acid residues in a sample (glycan) to be analyzed are modified in a linkage-type-specific way (S2), a mass spectrum for the sample is obtained by mass spectrometry (S3). Based on the masses of the modified glycans estimated from the m/z values of the peaks observed on the mass spectrum, all possible monosaccharide compositions are exhaustively estimated under specific conditions including the kinds of monosaccharides and the range of the number of occurrences of each monosaccharide (S4). Monosaccharide composition candidates listed for each peak are narrowed down by using the mass difference between different modifications of a sialic acid residue generated by the linkage-type-specific modification (S5).

Abstract: Disclosed is a method of preparing a sample that is suitably used for analysis of a glycoprotein or glycopeptide. A first reaction is performed to modify or remove at least one primary amino group contained in a peptide moiety of a glycopeptide or glycoprotein. Thereafter, a second reaction is performed. The second reaction is a reaction capable of modifying a carboxy group of sialic acid of a sugar chain. After the second reaction, a derivative from ?2,3-linked sialic acid a derivative from ?2,6-linked sialic acid have different masses. Determination of the presence or absence of sialic acid in the sugar chain of a glycoprotein or glycopeptide and identification of the linkage type of sialic acid can be simply performed by mass spectrometry.

Abstract: In the method of preparing a sample for analysis, a reaction is performed that produces different modified product depending on the sialic acid linkage type when a sialic acid is bound to a sugar chain of an analyte. In this reaction, an analyte containing a sugar chain, an amine containing two or more carbon atoms, and a dehydration-condensation agent are used. The sialic acid linkage type can be identified by analyzing the resulting sample with mass spectrometry etc. This method is applicable not only to free sugar chains but also to glycopeptides and glycoproteins.