With the continuing advances in the miniaturization of analytical techniques, and in particular of microchip capillary electrophoresis, the challenge of rapid metal complex speciation can now be taken up. The discrimination between different chemical species of metal ions is important as the environmental toxicity, biological activity and availability of many metals is often species dependent. Extensive electrophoresis studies have focused on speciation of low molecular
weight metal complex speciation. However, limited research has focused on the separation of different stoichiometries of species within the same metal-ligand system. This new research demonstrates the first rapid separation of individual species in equilibrium within selected metalligand systems by microchip electrophoresis. The transfer of speciation ability within a single metal-ligand system from capillary electrophoresis to microchip electrophoresis has been demonstrated with considerable success. This emphasises the immense future potential for microchip electrophoresis in the field of rapid chemical speciation.