Epichlorohydrin-D5, a deuterated form of epichlorohydrin, is primarily used as a labeled compound in research and analytical applications. It serves as a stable isotope internal standard in mass spectrometry, enabling precise quantification and tracking of epichlorohydrin in various samples, such as environmental, biological, or industrial matrices. Its deuterium labeling minimizes interference during analysis, ensuring accurate results in studies related to toxicology, metabolism, or environmental monitoring. Additionally, it aids in the development and validation of analytical methods for detecting epichlorohydrin residues, contributing to safety assessments and regulatory compliance in industries where this chemical is utilized.