Used as a stable isotope-labeled internal standard in mass spectrometry and gas chromatography for accurate quantification of acetophenone and related compounds in environmental, biological, and forensic samples. Its 13C-labeled structure allows clear differentiation from unlabeled analytes, improving detection sensitivity and measurement precision. Commonly applied in metabolic studies to trace reaction pathways and degradation mechanisms of aromatic ketones. Also utilized in pharmaceutical research for studying drug metabolism when acetophenone moieties are present in active compounds.