Used as a deuterated internal standard in analytical chemistry for quantifying ethylene thiourea residues in environmental and biological samples. Its primary application lies in mass spectrometry and liquid chromatography-mass spectrometry (LC-MS) methods, where it helps ensure accurate detection and measurement due to its isotopic distinction from non-labeled compounds. Commonly applied in pesticide residue studies, particularly for monitoring breakdown products of ethylene bisdithiocarbamate (EBDC) fungicides. Also utilized in metabolic and degradation pathway studies where tracking the fate of ethylene thiourea is required with high sensitivity and precision.