Professor D. Sparks (University of Delaware, USA) and his colleagues have reported an interesting application of quick X-ray absorption spectrometry to environmental science. The experiment is basically a continuous monochromator scan (0.3-0.6 sec for each spectrum) at the synchrotron beamline at Brookhaven National Lab. The main interest here is the initial oxidation rate of As(III) to As(V) by hydrous manganese(IV) oxide, because the toxicity and availability of arsenic to living organisms depends on its oxidation state at the interface to the water. The research team found that the initial apparent As(III) depletion rate constants are nearly twice as large as those measured with conventional, but much slower techniques. This indicates the necessity of further studies using such a rapid analytical method. For more information, see the paper, "Quantification of rapid environmental redox processes with quick-scanning x-ray absorption spectroscopy (Q-XAS)", M. Ginder-Vogel et al., Proc Nat Aca Sci, 106, 16124 (2009).
