Used as an internal standard in analytical chemistry, particularly in gas chromatography-mass spectrometry (GC-MS) for the quantification of phthalates in various samples. Its deuterated structure ensures minimal interference with the analysis, providing accurate and reliable results. Commonly applied in environmental testing to detect phthalate contamination in water, soil, and air. Also utilized in biomedical research to study phthalate exposure and its effects on human health, especially in urine or blood samples. Its stability and isotopic labeling make it a critical tool for precise measurement in complex matrices.