Hydroquinone-D6 is widely used as an internal standard in analytical chemistry, particularly in mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy. Its deuterated structure allows for precise quantification and analysis of non-deuterated hydroquinone and related compounds in complex mixtures. This application is crucial in pharmaceutical research, environmental testing, and metabolic studies, where accurate measurement of hydroquinone levels is essential. Additionally, it serves as a tracer in mechanistic studies to understand chemical reactions and pathways involving hydroquinone, providing insights into degradation processes and metabolic transformations. Its stability and isotopic purity make it a reliable tool for high-precision analytical applications.