For a molecular analysis, the sample is typically prepared in the laboratory and then separated into its individual components using a chromatograph. Subsequently, these components are ionized through an ion source, or „charged,“ allowing them to be „weighed“ in a mass spectrometer (MS), with their respective mass attributed to a specific molecule.
Usually, such an analysis requires a chromatograph for liquid (LC) or gaseous substances (GC), an ion source, and a mass spectrometer (LC-MS or GC-MS). With Direct MS, the labor-intensive sample preparation in the lab and separation using chromatography are bypassed. Instead, the sample is simply held directly in front of the inlet of a mass spectrometer. The sample can thus be „sniffed“ at atmospheric pressure.