Preliminary speciation study of Co(II)-citrate system by ion pairing-reversed phase chromatography coupled to UV detector

A review of recent trends in electrospray ionisation-mass spectrometry for the analysis of metal-organic ligand complexes

Electrospray ionisation-mass spectrometry (ESI-MS) is used in a wide variety of fields to examine the formation, stoichiometry and speciation of complexes involving metals and organic ligands. This article reviews the literature in this area over the past 5 years, examining trends in ESI-MS use and novel applications that enhance the scope of the technique. ESI-MS can provide direct information on changes in speciation with metal:ligand ratio and pH, identify metal oxidation state directly and allow insight into competitive interactions in ternary systems. However, both the instrumental set-up and artefacts in the electrospraying process can affect the species distribution observed, and changes in solution chemistry can affect the relative ion intensity of species. Therefore, ESI-MS data is at its most powerful when corroborated by data from other experimental techniques, such as pH potentiometry. The challenges in interpreting direct ESI-MS data quantitatively are discussed in detail, with reference to differences in the ion intensities of species, signal suppression and quantifying species distributions. The use of HPLC-ESI-MS is also reviewed, highlighting challenges and applications. Overall, the need for more standard reporting of quality assurance data is discussed, to strengthen the applications of ESI-MS to metal-organic ligand complexes further.

An interdisciplinary approach to investigate the impact of cobalt in a human keratinocyte cell line

Since in nuclear power plants, risks of skin contact contamination by radiocobalt are significant, we focused on the impact of cobalt on a human cutaneous cell line, i.e. HaCaT keratinocytes. The present paper reports an interdisciplinary approach aimed at clarifying the biochemical mechanisms of metabolism and toxicity of cobalt in HaCaT cells. Firstly, a brief overview of the used instrumental techniques is reported. The following parts present description and discussion of results concerning: (i) toxicological studies concerning cobalt impact towards HaCaT cells (ii) structural and speciation fundamental studies of cobalt-bioligand systems, through X-ray absorption spectroscopy (XAS), ab initio and thermodynamic modelling (iii) preliminary results regarding intracellular cobalt speciation in HaCaT cells using size exclusion chromatography/inductively coupled plasma-atomic emission spectroscopy (SEC/ICP-AES) and direct in situ analysis by ion beam micropobe analytical techniques.