In a first embodiment, a spectroscopy device comprises a preheater, an ionizer, and a differential ion mobility spectroscopy (DMS) analyzer. The preheater is disposed to heat inlet air to 150° C. or more. The ionizer is disposed to receive and ionize heated inlet air from the preheater. The differential ion mobility spectroscopy (DMS) analyzer has a reception element configured to detect ionized chemical agents in the inlet air.In a second embodiment, a spectroscopy device comprises a DMS detector and a controller. The DMS detector comprises an ionizer disposed to receive and ionize inlet air at 150° C. or more, and an analyzer disposed to selectively receive ions from the ionizer under varying radio frequency voltage and compensation field voltage. The controller is configured to flag at least one chemical agent as present in the inlet air upon reception of negatively charged ions by the analyzer under corresponding values of the radio frequency voltage and the compensation field voltage.