Determination of U(Ⅵ) by Raman Spectroscopy

A new method via Raman spectroscopy for determination of U(Ⅵ) in aqueous and organic solutions was developed. The concentration of U(Ⅵ) can be quantified by the Raman band of UO²⁺₂, which is 870 cm^-1 in aqueous solutions and 860 cm^-1 in organic solutions. In the aqueous phase, a good linear relationship is obtained between the Raman signal and concentration of U(Ⅵ) in the range of 5.0-450.0 g/L, with the r²= 0.9999. The detection limit is 1.2 g/L. The detection limit can be reduced to 0.2 g/L by increasing the integration time. The existence of nitric acid and fission products has no effect on the detection of U(Ⅵ). The s_r is no more than 1.4%(n=6) for detection of 70.0 g/L U(Ⅵ), with 0.5-4.0 mol/L HNO₃. The recoveries are in the range of 98.3%-101.6%. In organic solutions, the linearity is observed in the range of 5.0-107.0 g/L with r²=0.9990 and a limit of detection of 0.7 g/L. With the advantage of simple, rapid, green and no interference of internal substance, the method is applicable for in situ detection of U(Ⅵ) in aqueous and organic solutions.