Atomic Spectrometry Update: review of advances in elemental speciation

This is the seventh Atomic Spectrometry Update (ASU) to focus on advances in elemental speciation and covers a period of approximately 12 months from December 2013. This ASU review deals with all aspects of the analytical speciation methods developed for: the determination of oxidation states; organometallic compounds; coordination compounds; metal and heteroatom-containing biomolecules, including metalloproteins, proteins, peptides and amino acids; and the use of metal-tagging to facilitate detection via atomic spectrometry and relating to elemental speciation. The review does not specifically deal with fractionation, sometimes termed operationally defined speciation. The focus of the research reviewed includes those methods that incorporate atomic spectrometry as the measurement technique. However, because speciation analysis is inherently focused on the relationship between the metal(loid) atom and the organic moiety it is bound to, or incorporated within, atomic spectrometry alone cannot be the sole analytical approach of interest. For this reason molecular detection techniques, such as mass spectrometry, fluorescence and ultra-violet spectroscopy are also included where they have provided a novel approach to speciation analysis. As in previous years, As and Se speciation continues to dominate the current literature, with many derivative type papers being published, exploring all facets of the established analytical protocols used in these areas. Once again there has been an increase in the number of publications in the area of macromolecular analysis, particularly work concerned with metallomics or metalloproteomics and also tagging or labelling of organic molecules to make them detectable by atomic spectroscopy techniques. The use of atomic and molecular mass spectrometry in combination, either simultaneously on-line or sequentially off-line, continues to offer the best main-stream approach for most conventional applications, particularly when standards for the species under investigation are not available and high mass accuracy MS instrumentation can be used for identification.