The Thermo Scientific Dionex Ultimate 3000 LC system is applied for the related substances analysis of 3-(trifluoromethyl) aniline. The analysis was performed on a Thermo Scientific Syncronis C18 HPLC column using the method described in this application note. All the known impurities were well resolved from the main peak. The critical resolution between main peak and its known impurity [4-(trifluoromethyl) aniline was above 2.0