This study demonstrates a routine screening of drugs to identify and quantify potential genotoxic compounds. In this Application Note, we used an Agilent 6545 Q-TOF LC/MS system to acquire accurate mass data of samples containing chlorhexidine as the drug substance. Agilent MassHunter Mass Profi ler software was used to mine the data and compare different samples to generate a differential list of compounds. An accurate mass database search against the differential list identifi ed 4-chloroaniline, a potential genotoxic compound. All Ions MS/MS acquisition mode was used to confi rm 4-chloroaniline by MS/MS library matching, and quantify it using external standards. This workflow is suitable for batch-to-batch sample analysis for detecting and quantifying known potential genotoxic compounds