A novel ion source for ambient mass spectrometry (switched ferroelectric plasma ionizer or “SwiFerr”), which utilizes the ambient pressure plasma resulting from a sample of barium titanate [001] whose polarization is switched by an audio frequency electric field. High yields of both anions and cations are produced by the source and detected using an ion trap mass spectrometer. Protonated amines and deprotonated volatile acid species, respectively, are detected in the observed mass spectra. Aerodynamic sampling is employed to analyze powders of drug tablets of loperamide and ibuprofen. A peak corresponding to the active pharmaceutical ingredient for each drug is observed in the mass spectra. Pyridine is detected at concentrations in the low part-per-million range in air. The low power consumption of the source is consistent with incorporation into field portable instrumentation for detection of hazardous materials and trace substances in a variety of different applications.