Used as a stable isotope-labeled internal standard in gas chromatography-mass spectrometry (GC-MS) for accurate quantification of hexanal in complex biological and environmental samples. Its deuterated structure allows clear differentiation from the non-labeled compound, minimizing interference from matrix components. Commonly applied in studies of lipid oxidation, food spoilage, and breath analysis for biomarker detection, where precise measurement of volatile organic compounds is critical. Also employed in metabolic tracing experiments to monitor reaction pathways and degradation processes in controlled systems.