Extremely low heavy metal concentrations are often detected using atomic spectroscopy with matrix interferences due to the existence of organic matter or non toxic metals of the earth's crust (i.e. silicium, aluminium, iron, alkalines and alkalines earths). Many of the techniques that are widely used for the pre-concentration of analytes or/and the removal of the sample's matrix exhibit inherent limitations during their application, are time-consuming and slow down the overall analytical procedure, contravening the current technological trend towards fast and efficient instrumental techniques for the determination of heavy metals.

This project aims at the synthesis and chemical modification of magnetic silica and ceria participles that are capable of bearing proper active groups for the selective enrichment of heavy metals and the simultaneous removal of matrix components that may cause interferences. Thus, nanomaterials containing active groups that irreversibly withhold heavy metals without any need for a desorption step, will be used, offering at the same time improved selectivity. Multi-element determination of heavy metal trace quantities will be conducted using slurry sampling and electro thermal vaporization (ETV) coupled with ICP-OES and ICP-MS. The development of this new combinatorial technique will also enable its use in flow conditions with a proper system of sample injection in constant flow (FIA). Furthermore, the synthesis of magnetic nanoceria which will be used for the ““on line trapping”” of metal hydrides, such as As, Se, Sb and Sn and their subsequent insertion into an electrothermal AAS, is suggested. The application of the renewable surface of the adsorbent in pre-concentration flow conditions, in combination with ““on bead detection””, eliminates the clogging problem that appears during classical solid phase extraction in cartridges and negates the need for the desorption of analytes from the sorbing material.

This project's expected scientific and technological results are the following:

  • Synthesis of chemically modified nanomaterials with active groups for the selective enrichment of heavy metals and the simultaneous removal of interfering substances. Overriding the elution step allows the use of adsorption nanomaterials with active groups that react irreversibly with the heavy metals.
  • Multi-element determination of trace quantities of heavy metals in the surface of nanomaterials as a result of their selective interaction. A slurry sampling technique will be used for the sample introduction to ICP-OES and ICP-MS.
  • Synthesis of magnetic ceria nanomaterials that allow pre-concentration of metal hydrides and their determination with HG-ETAAS.
  • Applying these techniques in flow conditions after proper modifications of an FIA system. The application of a renewable surface in combination with on bead detection offers a system that can be automatized and overcomes difficulties due to clogging problems of traditional SPE cartridges as well as the elution step of analytes from the sorbing material for the multi-element determination with ICP.

The expected benefits by the implementation of this project:

  • Synthesis of cheap magnetic nanomaterials properly modified for their easy management during sample treatment,
  • Usage of the synthesized nanomaterials in flow conditions to overcome inherent problems of the SPE cartridges,
  • Higher enrichment factors, given that the nanoparticles with the heavy metals are inserted in the detecting device without further dilution, as during an elution step,
  • on-bead detection doesn't require reversible sorbing procedures
  • the presence of nanoparticles in the ICP and/or the HG-ETAAS increases the vaporization efficiency and the atomization during the electrothermal vaporization.