New approaches to elemental speciation

Elemental speciation has been one of the principal growth areas in analytical atomic spectrometry. This reflects the recognition that in the environmental and biological sciences, the transport, pool dynamics and toxicology of the elements are dependent on their chemical speciation. Significant progress has been made in elemental speciation by the direct coupling of separation techniques, notably the various forms of chromatography, to powerful elemental detectors such as ICP-MS. However, the strength of such hyphenated techniques, that they provide almost unambiguous identification of elemental associations, is often achieved at the expense of losing information about the ligands that are responsible for the speciation. The challenge must be to bring the two approaches to bear simultaneously so that quantitative and qualitative information on both the inorganic and organic components can be obtained simultaneously. Capillary electrophoresis (CE) has developed into one of the most powerful separation techniques offering rapid separations with high resolution. However, these advantages are offset by low sensitivity which is a consequence of the very small (nl) samples that the technique can handle. These problems can be overcome by using high sensitivity detectors and hence the interest in coupling CE to .ICP-MS. Coupling of CE to ICP-MS (CE-ICP-MS) has, therefore, the potential to provide rapid and quantitative elemental speciation information that is complementary to that provided by other techniques. This thesis describes an interface for coupling CE to ICP-MS and its applications to some common metal species. A particular interest in this work has been to investigate the potential of CE for studying metal complexes with humic and fulvic acids. A technique that offers potential for determining both free element and complexed forms, without prior separation IS electrospray/ion spray ionisation-mass spectrometry. Preliminary work is presented that investigates the applications of electrospray/ion spray ionisation-mass spectrometry to some common metal-ligand systems.