Abstract: Provided is a quantification method for a sulfur-containing organic compound. The quantification method may quantify the sulfur-containing organic compound without limitation. Preferably, the quantification method is more effective for quantifying organic compounds of which quantification is difficult to perform, such as a macromolecule such as a biomaterial, or the organic compound having a hygroscopic property or being present in a hydrated form, and significantly effectively quantifying high purity standard materials of peptide or protein among the biomaterials.