Analysis method of carboxylic acid anhydride

Abstract

A method for analyzing a sample containing a carboxylic acid anhydride includes, in a stated order, a first step of causing the sample to pass through a column together with a first mobile phase to detect a carboxylic acid anhydride eluted from the column in supercritical fluid chromatography, and a second step of causing a second mobile phase to pass through the column by switching the mobile phase from the first mobile phase to the second mobile phase after a lapse of a retention time of the carboxylic acid anhydride to detect at least one of a carboxylic acid ester and a carboxylic acid eluted from the column. The first mobile phase is a mixture of carbon dioxide and an organic solvent having no hydroxyl group, and the second mobile phase is a mixture of carbon dioxide, an acid, and an organic solvent having a hydroxyl group.

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