INTRODUCTION Gas chromatography combined with high-resolution time-of-flight mass spectrometry (GC-HRTOFMS) is a powerful tool for the analysis of complex mixtures. The AccuTOF GC-Alpha (JMS-T2000GC) mass spectrom-eter is fast, accurate and sensitive with high mass-resolving power and high mass accuracy. Data analysis based on database matching alone does not necessarily provide reliable assignments for com-pounds that have similar electron ionization (EI) mass spectra or compounds that do not have entries in mass spectral databases. JEOL msFineAnalysis software provides automated analysis that makes use of all of the information available from a GC-HRTOFMS analy-sis: elemental composition determination from soft and hard ionization with exact mass measurements and accurate isotope data, database searching, frag-ment ion coverage, and retention index data. In this work, GC-MS analysis of a 12-year-old standard drug mixture was carried out with the AccuTOF GC-Alpha (JEOL JMS-T2000GC) mass spectrometer using the combination electron ionization/photoionization (EI/PI) ion source and the chemical ionization (CI) ion source. Data analysis using JEOL msFineAnalysis software carried out chromatographic deconvolution and identified the drugs and impurities by combining and integrating all of the information from EI and PI analysis. Please download the application note below to read more.