Used as a stable isotope-labeled internal standard in environmental and biological monitoring to accurately quantify hexachlorobenzene residues using mass spectrometry techniques. Its primary application lies in analytical chemistry, where it helps correct for losses during sample preparation and ensures precise measurement of the non-labeled compound in complex matrices such as soil, water, and biological tissues. Due to its identical chemical behavior but distinct mass signature, it enables reliable tracking and differentiation from naturally occurring hexachlorobenzene in contamination studies and metabolic research.