Occurrence of vanadium ion in serum albumins

Vanadium was shown to be a contaminant in Sigma-grade serum albumins, fraction V. The levels of vanadium detected by neutron activation analysis were: bovine 16.7, ovine 10.0, rabbit 9.1, porcine 3.9, and human 0.19 micrograms/g protein. According to the ESR spectra, the vanadate form (+5 oxidation state) was strongly suggested as a chemical form present in albumins. Dialysis against a chelating agent was quite effective for removal of the metal ion.