Figure 9.

Comparison of photo-reduction at various synchrotron sources in V K-edge XAS of freeze-dried biological samples: first and second X-ray absorption near-edge scans for V(V/IV) species in biological media (neat freeze-dried samples, 295 K). The reaction products of Na₃[VO₄] (1.0 mM) with undiluted calf serum or with BSA solution (0.50 mM in HEPES-buffered saline, pH 7.4) were prepared as described in §2. Designations of the synchrotron sources: ANBF is the Australian National Beamline at the Photon Factory, KEK, Tsukuba, Japan; AS is the XAS beamline at the Australian Synchrotron, Melbourne, Australia; and SSRL is the Stanford Synchrotron Radiation Lightsource BL7-3, Menlo Park, USA.