Evaluation of dissolved species of lanthanum in the solutions containing different amino acids by cation-exchange chromatography coupled with electrospray ionization mass spectrometry

Dissolved species of lanthanum in the solutions which contained ethylenedia mine tetraacetic acid (EDTA) and L-tryptophan, respectively, were evaluated by electrospray ionization mass spectrometry. The stability of the species of La complexes during the cation-exchange chromatographic separation proc ess was discussed. The results indicated that the speciation of lanthanut.1 in the solution was remarkably influenced by the dissociation of the La sp ecies, which is in turn depended on the cation-exchange column selected.