Among the various methods used for characterizing plastics, pyrolysis (Py) GC/MS and thermal desorption (TD) GC/MS are widely used for both qualitative and quantitative analyses. These are simple techniques that provide detailed information about the samples. In this application note, we report the analysis of additives in plastic by using a thermal desorption system and a JEOL JMS-T100GCV 'AccuTOF GCv' GC-TOFMS. Identification of the analytes was accomplished by library search and accurate mass measurement. Additionally, isotope cluster pattern matching was performed using the 'Mass Spec Tools™' software to help identify an unknown compound that was present in the sample.