Study of Laser Desorption-Ionization of [Co(H2O)6](NO3)2, [Co(H2O)7]SO4, [Co(NH3)5Cl]Cl2, [Co(NH3)4CO3]NO3, [Fe(H2O)6]SO4 and [Fe(H2O)7](NO3)3 Complexes by Time of Flight Mass Spectrometry

Document Type : Research Article


Chemistry Department, Isfahan University of Technology, Isfahan, I.R. IRAN


The time of flight mass spectrometry is an efficient technique for the identification and characterization of chemical materials. In this method, the ions produced by the interaction of laser radiation with the sample, are accelerated in the ionization region and after obtaining enough kinetic energy are separated from each other in the absence of an electrical field based on their mass to charge ratio in a flight tube and then, reach to the detector at different times. In this work, the time of flight mass spectra of several inorganic complexes such as [Co(H2O)6](NO3)2, [Co(H2O)7]SO4, [Co(NH3)5Cl]Cl2, [Co(NH3)4CO3]NO3, [Fe(H2O)6]SO4 and [Fe(H2O)7](NO3)3 were recorded using the desorption-ionization (LDI) of sample on the aluminum plate. The laser light with a wavelength of 1064 nm (infrared region) was used for the LDI. Comparison of the recorded mass spectra of Co complexes with H2O ligands with those of Co complexes with NH3 ligands showed that the metal-oxygen bond is stronger than the metal-nitrogen bond because the different ionic species containing the metal-oxygen bonds are seen in the mass spectra of complexes containing H2O as a ligand. The absence of the peak related to the intact complex in the recorded mass spectra showed that these complexes have not stability against the laser radiation. Also, the effect of different counterions on the mass spectra of complexes with the same metal and ligands was investigated and it was found that the mass spectra are independent of the kind of counterion.


Main Subjects

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