Used primarily as an internal standard in analytical chemistry, especially in mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. It helps in the accurate quantification of leucomalachite green residues in biological samples, such as fish and seafood, by compensating for matrix effects and instrument variability. Its deuterated structure allows clear differentiation from non-labeled compounds during detection, improving measurement precision and reliability in food safety and regulatory testing.