Compound, diagnostic agent, nuclear magnetic resonance analysis method, nuclear magnetic resonance imaging method, mass spectrometry method and mass spectrometry imaging method
To produce a labeled compound for a selected biological substance not using a radioisotope atom which has a risk of exposure to radioactivity and limitation on handling time but using a stable isotope atom; and that the labeled compound can be measured with good sensitivity separably from naturally occurring compounds of the selected biological substance which are substituted with the stable isotope atom. Choline as a biological substance is labeled by substituting the nitrogen atom of the quaternary ammonium group and all the carbon atoms of the methyl group attached to the nitrogen atom with respective isotopes 15N and 13C and used as a diagnostic agent.