The chemical ionization inlet (The Multi-scheme chemical IONization inlet, MION) is capable of fast switching between multiple reagent ion schemes. The proprietary technology was developed at Karsa (patent application WO2018050962) and is the only commercially available APCI system capable of rapidly switching reagent chemistry by only injecting reagent ions (and not reagent gas) into the sample air. This assures that the sample is not affected by the presence of un-charged reagent. The application of complementary ion modes in probing the same steady-state reaction mixture enables a far more complete picture of the detailed autoxidation process. In a demonstration of the approach, HO₂ radical and least-oxidized reaction products were retrieved with Br− ionization, whereas the highest-oxidized reaction products were detected in the NO₃⁻ mode, directly providing information on the first steps and on the ultimate endpoint of oxidation, respectively. In the past, reagent switching was not practical and users would run two mass spectrometer systems in parallel to get the same information as can be gained from using a MION with only one mass spectrometer.  The ion source in its standard configuration allows switching between two reagents within a second timescale, and it offers a mode to monitor ambient ions. It integrates well with API-TOF, but can be coupled to most commercially available mass spectrometers with API interface. Please inquire about the possibility integrate to your system.