Used as a labeled internal standard in analytical chemistry, particularly in mass spectrometry, for the quantification of similar aromatic amines in complex matrices. Its deuterated form enhances accuracy by minimizing interference from non-deuterated compounds. Applied in environmental and toxicological studies to monitor exposure to harmful aromatic amines, such as those found in tobacco smoke or industrial processes. Also utilized in research to study metabolic pathways and degradation processes of biphenyl derivatives in biological systems.