We describe an introduction to Gas Chromatography – Mass Spectrometry (GC/MS) based laboratory that is compatible with the first general chemistry laboratory. The principles and concepts of chromatography, mass spectrometry, and molecular formula determination were explored. These concepts were investigated in the context of a possible arson fire. The students were directed to find the molecular formula, boiling point, and other properties of an unknown liquid. Databases and literature were used extensively to complement and compare with the experimentally derived data and results.