Used as a deuterated internal standard in analytical chemistry, particularly in gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). Its primary application is in the accurate quantification and detection of polychlorinated dibenzofurans (PCDFs) in environmental and biological samples. The deuterated label provides a distinct mass shift, allowing clear differentiation from non-labeled analogs, improving measurement precision and reducing matrix interference. It is especially valuable in monitoring dioxin-like compounds in air, soil, water, and food due to its stability and consistent behavior during sample preparation and analysis.