Used as a stable isotope-labeled internal standard in mass spectrometry for the detection and quantification of N-Nitrosodiethylamine (NDEA) in pharmaceuticals and biological samples. Its deuterated structure allows for accurate differentiation from the non-labeled compound during analytical testing, improving precision in trace-level impurity analysis. Commonly applied in genotoxic impurity testing to meet regulatory requirements in drug development. Also used in metabolic studies to track the fate of nitrosamines in biological systems without altering the chemical behavior due to isotopic labeling.