ANALYSIS OF RUTHENIUM CARBONYL-PORPHYRIN COMPLEXES - A COMPARISON OF MATRIX-ASSISTED LASER DESORPTION IONISATION TIME-OF-FLIGHT, FAST-ATOM-BOMBARDMENT AND FIELD DESORPTION MASS-SPECTROMETRY/

The mass spectrometric characterisation of ruthenium carbonyl-porphyri n complexes and the corresponding porphyrins is described. Matrix-assi sted laser dcsorption/ionisation time-of-flight mass spectrometry (MAL DI-TOF-MS), Past-atom bombardment mass spectrometry (FAB-MS), in both lon -resolution (LR) and high-resolution (HR) modes, and field desorpt ion mass spectrometry (FD-RIS) have been used and compared in detail. MALDI-TOF-MS turned out to be ideal for rapid screening of potential s ynthetic pathways. FAB-MS proved to be especially useful in establishi ng elemental compositions bg HR measurement, Whereas the porphyrins ga ve very good molecular ion intensities, the ruthenium carbonyl complex es exhibited abundant carbon monoxide (CO) loss in MALDI-TOF-MS and st ill a measurable CO loss in FAB-MS. Only FD-MS yielded the molecular i on as the base peak of the spectrum in all cases. Optimised FD emitter heating conditions allow the remaining portion of the thermally-induc ed CO loss to be significantly reduced.