We plan to investigate the effect of bacterial siderophores and phytosiderophores on the availability of metalloids and lanthanoids to plant roots and their impact on the biogeochemical cycling of these elements. For the quantification of the formed complexes and investigations on the stability of complexes we need some standard material. Is it possible to buy these chemicals? Or is the only way to obtain these chemicals the separation and purification of root exudates from e.g. Hordeum vulgare?