ACE 1100 Ion-Molecule Reaction Mass Spectrometer(IMR-MS) is an optimized
mass spectrometer for qualitative and quantitative analysis of Volatile Organic Compounds(VOCs).
GC-MS and LC-MS use chromatography system(GC, HPLC) for separation of analysis compounds
and need the interface between mass spectrometer and chromatography system.
In contrast with GC-MS & LC-MS, IMR-MS loads sample directly into the mass spectrometer and
immediately can get analysis results in real-time. It can be used not only in the laboratory,
but also on-site analysis is required, the place where the on-line monitoring is necessary.
Analysis process of IMR-MS follows reagent ion(precursor ion) production →
precursor ion selection → Ionization of analytes(precursor ion react with analytes) →
qualification & quantitation procedure
The ionization step of analytes is an essential procedure when you use a mass spectrometer for analysis of sample compounds,
and typical ionization methods in mass spectrometry are Electron Impact Ionization(EI) method and Chemical Ionization(CI) method.
IMR-MS uses a soft chemical ionization method, and it ionizes the sample molecule itself or minimizes the fragmentation of the target molecule.
By this ionization method, you can get a simple and accurate mass spectrum.
These are ion sources for chemical ionization of sample molecules. Microwave plasma produces some ions
such as H₃O+, NO+, O₂+ using normal water(H₂O), and air(N₂, O₂). These reagent ions pass through 1st mass filter
and according to analysis condition, a specific ion or three ions move to the reaction chamber for the next step.
The reagent ion(or ions) moves to the reaction chamber react with a loaded sample molecule in this chamber to produce molecular ions.
In this ionization process, different kinds of reaction mechanisms are applied such as Proton transfer,
Electron transfer, dissociative Electron transfer, Hydride abstraction, Association. By these different ionization mechanisms,
each reagent ion produces specific molecular ions which will help to identify the compound.
Molecular ions are separated and selected according to their mass-to-charge ratio in the second mass filter
and are converted into an amplified electric current in the detector(Electron multiplier).