Atomic-absorption spectrometric, neutron-activation and radioanalytical techniques for the determination of trace metals in environmental, biochemical and toxicological research

Radioanalytical techniques and atomic-absorption spectrometry have been used for the micro-determination of vanadium in biological specimens such as human tissues and body fluids in environmental, biochemical and toxicological research. The use of 48V as a radiotracer permitted investigations on the vaporisation and retention mechanisms of vanadium. Higher vanadium oxides are probably converted into lower oxides, decomposing to VO in gaseous form, followed by the dissociation to 'free vanadium' and oxygen. It was found that about 20% of the 48V radioactivity was consistently retained in the graphite tube after 10 repeated introductions and firings of 50 μl of 50 ng ml-148V-labelled vanadium solution. However, the amount retained, probably in the form of carbide, does not vaporise under the conditions used for the analysis. Determinations of vanadium at the parts per billion level in 10 urine samples by neutron-activation analysis and by graphite furnace atomic-absorption spectrometry showed agreement that can be considered satisfactory for practical purposes. (author)