Used as a deuterated internal standard in analytical chemistry, particularly in mass spectrometry and gas chromatography, to accurately quantify Diisodecyl Phthalate (DIDP) in environmental and biological samples. Its labeled structure allows for differentiation from non-deuterated compounds, improving measurement precision and reliability. Commonly applied in studies monitoring phthalate exposure, migration from plastics, and environmental contamination. Also utilized in metabolic and toxicokinetic research to trace the behavior of phthalates in biological systems without interference from endogenous sources.