Used as a stable isotope-labeled internal standard in mass spectrometry and gas chromatography-mass spectrometry (GC-MS) analyses. Its deuterated structure allows for accurate quantification of cyclopentanone and related compounds in complex mixtures by minimizing interference from matrix effects. Commonly applied in metabolic studies, environmental analysis, and pharmaceutical research where precise tracking of ketone derivatives is required. The labeled compound maintains similar chemical behavior to non-labeled cyclopentanone, ensuring reliable calibration and detection sensitivity.