Used as a stable isotope-labeled internal standard in mass spectrometry-based bioanalytical assays for quantifying piperazine derivatives in pharmaceutical and metabolic studies. Its deuterated structure allows for accurate differentiation from non-labeled compounds in complex biological matrices, enhancing measurement precision. Commonly applied in drug development, pharmacokinetics, and metabolism research where high sensitivity and specificity are required. Also useful in tracing metabolic pathways due to resistance to enzymatic degradation compared to non-deuterated analogs.