拉曼光谱内标法定量分析Purex 有机体系中的 U（Ⅵ）

摘要

本工作研究了 Purex 后处理流程模拟有机料液中 U(Ⅵ)的定量分析方法。首先扣除硝酸铀酰有机溶液拉曼光谱的荧光背景,并以30%TBP/煤油位于1065 cm-1处的特征峰为内标峰,将 U(Ⅵ)位于860 cm-1处对称伸缩振动峰(ν1)强度与内标峰强度的比值,对铀浓度绘制标准曲线,在 U(Ⅵ)质量浓度为5.0~107.0 g/L范围内,标准曲线为 y =0.0636x +0.357,r 2=0.999。经过内标法处理后的标准曲线具有更好的稳定性,75 d后相对强度标准曲线为 y =0.0624x+0.489,r 2=0.999。F 检验与 t 检验证明,在显著性水平α=0.05时,两条标准曲线在分析精度与斜率上无显著性差异。使用内标法后,可透过容器壁直接分析铀浓度,容器对检测结果的影响较小,5种容器对 U(Ⅵ)检测影响相对误差均不高于3.7%,故检测过程无需进行样品的转移及分装,简化了实验步骤。经内标法修正后,改变拉曼光谱仪的积分时间和激光功率基本不影响 U(Ⅵ)的定量检测,从而可选择合适的参数以适应不同浓度 U(Ⅵ)溶液分析的需要。%The quantitatively detection of U(Ⅵ)in 30%TBP/kerosene in Purex process was studied.The baseline of the Raman spectra was corrected,and the Raman band of U(Ⅵ) which is considered as symmetric stretching modeν1 (860 cm-1 )and the band of the organic solvent located at 1 065 cm-1 were selected as quantitative peak and internal standard reference peak,respectively.Take the ratio of the intensities as relative peak intensity,the standard curve was plotted,which is y =0.063 6x +0.357 with r 2 =0.999 in the range of 5.0-107.0 g/L of U(Ⅵ).The standard curve using the internal standard method shows good stability,which changes to y =0.062 4x +0.489 with r 2 =0.999 after 75 d.The analytical precisions and slopes of the two standard curves show no significant differences when significance level α is equal to 0.05 by F test and t test. The linearity shows good repeatability,thus it can be used for a long period without refreshing it.With the method of internal standard,different containers had little effect on the Raman spectra of uranyl organic solutions,thus the detection can be conducted through the container walls,which had the advantage of simplifying the detection.The detection of U (Ⅵ)in five containers shows the relative deviations of no more than 3.7%,therefore,it has no need to change the containers when detecting the samples.Take the use of the internal standard method,then the integral time and the laser power have little influence on the determination.Thus the parameters can be selected to meet the need of detecting uranyl solutions with different concentrations.