Purity testing of organometallic catalysts by micro liquid chromatography-electron ionization mass spectrometry

Summary A micro liquid chromatography-mass spectrometry system utilizing 100 μm i. d. packed capillary columns has been used for purity testing of organometallic catalysts. The total effluent, 1 μLmin⁻¹ from the column, was introduced directly into the ion source of a bench-top quadrupole mass spectrometer and electron ionization mass spectra were acquired. In full scan mode a mass limit of detection of 10–15 ng was achieved for the organometallic compounds investigated. The catalysts dimethyl pentamethylcyclopentadienyl iridium dimethylsulphoxide (Cp^*Ir(DMSO)Me₂) and di(pentamethylcyclopentadienyl dichloro iridium) ((Cp^*IrCl₂)₂) were purity tested and their electron ionization mass spectra recorded. Impurities present down to 1% of the main compound could be determined using large volume injection.