A method for providing in situ chemical transformation and ionization of a portion (e.g., inorganic oxidizer) of a sample via an analyte detection system is disclosed herein. The method includes introducing a gas into an ionization source of the analyte detection system via an inlet. The method further includes generating ions within the ionization source and directing the gas and generated ions through and out of the ionization source and to the sample. The sample is located proximal to the ionization source in an ambient environment. The ions chemically react with the sample and desorb and ionize an analyte from the sample, the analyte being generated from the inorganic oxidizer, the desorbed analyte having a lower melting point and/or better desorption kinetics than the inorganic oxidizer. The method further includes receiving the desorbed analyte via an analyzer of the analyte detection system.