Over the years other research projects were as well ongoing, some of which are summarised below.

Nutraceuticals

Total element content in nutraceuticals: in this project we determined the total content of essential and non-essential elements in a range of food supplements sold over the counter in UK and US.

The supplements were mainly based on algae, garlic fish and krill oil. In addition to total element content the amount of inorganic arsenic was estimated in the samples.

Publication

Archaeology

ArchaeologyThe element content in soil cores can give information about past human activity. A study of peat cores taken from south-west England showed that the scale of tin mining in the area increased significantly during Roman times 100-400 AD and that Anglo-Saxons also significantly exploited these mines. Significant copper and lead exploitation in the area started earlier.

Furthermore have we looked at imaging and elemental fingerprint for the identification of glass types mainly by LA-ICP-MS analysis. One project studied the origin of Roman glass beads found in Scotland.

Some of our publications in this field:

Cobalt speciation

Cobalt SpeciationCobalt is essential for humans only in form of Vitamin B12, which is a co-factor of several enzymes. Its speciation in biological samples is difficult due to a) the instability of its different forms and b) its general low concentration in tissues.

A method was developed to distinguish between vitamin B12 bound cobalt and cobalt present as other species. It was possible to show that foetal liver content of vitamin B12 is gender specific and that it represents only about 45 % of the total cobalt.

Publications

Bio-Imaging

Elements are not homogenously distributed throughout tissues and show also on the cellular level distinct distribution patterns. The same is also applicable to organic molecules be it proteins, metabolites.

Bio-imaging involves the determination of the elemental or molecular distribution pattern. Combining information of elemental and molecular distribution from neighbouring thin-sections with histological information allows correlation between pathology, proteins and metal concentrations.

Metals are not homogenously distributed throughout tissues. They often are enriched in either specific cells or cell compartments. Bio-imaging using laser ablation-ICP-MS can show this inhomogeneity of the element distribution and may also give clues as toward disease mechanisms.

For example imaging of fungal infected tissue showed that iron and copper distribution changes due to infection and also showed that the host tries to combat the infection by changes in the copper metabolism. Whereas in case of bacterial infection the main change noticed was a significant increase of calcium in the infected area accompanied by a decrease of all essential elements.

Dynamic Bioimaging

Bio-imaging can also in certain cases be used to determine the isotope distribution in tissue and thereby help to understand the metabolism / kinetic of an element.

Bio-imaging of tissue sections obtained from feeding experiments with enriched stable isotopes conserve the metabolic turnover of the element(s).

Publications

Boron speciation

The boron content in high-purity silicon used in semi-conductor production is an important quality parameter during production. The quantification of boron in silicon matrix is difficult due to its generally low concentration.

In a collaboration with Elkem it was possible to show that boron quantification in silicon is also species depending. A method was developed to avoid the false quantification of boron in this type of material.

Publication

Boron Speciation

Metallo-protein speciation

Metallo-Protein SpeciationAbout 30 % of all proteins depend on one or more metals for their biological function. Most of these metals are only loosely complexed by the protein. There are several aspects of interest:

  • One is whether a protein requires a specific metal for its activity and the stoichiometry associated with it
  • another is the quantification of a known metalloprotein using species-specific isotope dilution for quantification. The standards for this can be produced depending on the protein chemically. One of the most suitable proteins for this is superoxide dismutase a copper/zinc depending enzyme.
  • The labile metal-protein bonds make the development of novel analytical methods challenging. We have made some advances in this area to reach the holy grail of absolute quantification of proteins.

Some of our publications in this field: