Abstract: "Hexavalent uranium in weakly acid solution produces with a large excess of ascorbic acid a yellow-brown color whose intensity under certain conditions is a linear function of uranium concentration. Chloride, nitrate, perchlorate, along with Fe, Cd, Mn, Na, Ca, Sn, Mg and Th are without effect on the color while phosphate, sulfate, fluoride, citrate, tartrate, oxalate, chromium, and vanadium and moderate amounts of Ni, Zn, Mo and Al interfere. A rapid ether extraction procedure for purification of the uranium has been developed."