Using a method that combines liquid chromatography, a mass spectrometer, and a single mass analyzer, tert-butyl4-((2-aminopyridin-3-yl)(nitroso)amino)piperidine-1-carboxylate) has been found (LC-MS).For Rimegepant Impurityseparation and quantification attain by using Hypersil BDS (C18, 100 x 4.6 mm, 3 m) column at the threshold of toxicological concern levels, no acceptable approach has yet been developedIn this work, a sensitive and reliable liquid chromatography-mass spectrometry method for the quantitative detection of impurity in rimegepant was developed and validated in accordance with the criteria of the International Council for Harmonization (ICH).The correlation coefficient of fitting for impurity exceeded 0.998, and the calibration curves displayed satisfactory linearity within the examined range. The proposed method's sensitivity was between 0.6 and 10.0 mg/mL. This method can be used to identify the impurity in rimegepant drug substance during manufacturing.