A new method for the determination of iron oxidation states by resonant and non‐resonant ionization mass spectrometry

Different compositions of micrometric particles of powdered iron oxides (Fe1−xO, Fe3O4 and Fe2O3) are examined by time-of-flight laser microprobe mass spectrometry. The positive-ion cluster distributions show a strong correlation with the stoichiometry of iron in the oxide. This correlation is more striking when the resonant process of iron at 293.7 nm is used. The bond dissociation energy of Fe–-O in the bulk Fe1−xO also affects the intensity distributions. It is very important to study and to identify the iron oxides because they could play a role in the toxicity of certain molecules which could be removed on the oxides.