Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry as a tool for speciation analysis?

The possibility of using MALDI-TOF MS for speciation analysis was investigated. The technique can be applied to determine molecular weight of species formed by an interaction of the reacting components (metal ions-ligand) and to get some information on complex formation or even partly on the speciation in solution. The main limitation is that aqueous samples are to be dried before analysis, which substantially changes the composition. Anyway, the information about solid phase or on formation of species in solution can be obtained and MS spectra reflect in some way the composition of the aqueous phase. In spite of this limitation, the method seems to be perspective because of high sensitivity. It has been applied for uranium determination in waters measuring intensity Of UO2+ ion, while low sample volumes (approximate to 1 muL) are needed.