A dual-ionization mass spectrometer includes a first mass spectrometer module forming a hard ionization mass spectrometer, a second mass spectrometer forming a soft ionization mass spectrometer, a vacuum ultraviolet light source positioned between the first and second modules, a housing encompassing the first and second sets of plates and the light source, and an inlet positioned to receive a sample of an analyte and provide it to at least one of the sets of plates. A method of detecting a substance includes receiving a sample of an analyte into a housing through an inlet, performing soft ionization mass spectrometry on the sample with a soft ionization mass spectrometer in the housing, performing hard ionization spectrometry on the sample with a hard ionization spectrometer in the housing if needed, and generating a detection result from at least one of the soft ionization spectrometry and the hard ionization spectrometry.