A soft ionization device is disclosed that comprises a series of electrodes (120, 122) having spacing less than the means free path of the molecules to be ionized. In some embodiments, the soft ionization device (99) is used in various applications that require ion or electron sources such as biological or chemical reactors, ion milling, and numerous replacements for conventional hot cathode systems. In another embodiment, a valence spectrometer is disclosed that is configured to variably ionize molecules (301) by their valiancy. In other embodiments, the ionization device is coupled to a spectrometer for the characterization of biological matter. Also disclosed is a preconditioner for preparing biological matter to be ionized.