共存离子对时间分辨荧光法测定痕量铀的影响
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摘要
时间分辨荧光法分析痕量铀具有灵敏度高、操作简便等优点,但是受共存离子的影响很大,准确度评价较低,分析结果误差过大。本工作研究了时间分辨荧光法测定焦磷酸体系中UO2+2时几种干扰离子如H+、Fe3+、NO-3等的影响,为痕量铀样品预处理方法的确定提供重要依据。结果表明:H+对UO2+2的荧光猝灭主要表现为荧光物质的破坏;NO-3对铀络合物荧光体系的影响表现为对激发光的吸收;Fe3+的影响表现为对激发光和荧光的吸收。对于质量浓度为2μg/L的铀溶液,当c(H+)=0.037 5mol/L时,UO2+2的荧光强度下降了44.4%;当ρ(Fe3+)=20mg/L时,UO2+2的荧光强度基本猝灭完全。
Interfering ions are the main influencing factors to time resolved fluorescence(TRF)analyses of trace uranium.The influence of H+,Fe3+and NO-3are studied in this paper.The fluorescence intensity of uranyl fluorescent complex is greatly affected by nitric acid.The fluorescence are completely quenched when the concentration of nitric acid is0.075mol/L.The concentration and lifetime of fluorescent complex are reduced by the addition of H+.The fluorescence intensity is also affected by Fe3+and NO-3because of the absorption of exciting light.
Interfering ions are the main influencing factors to time resolved fluorescence(TRF)analyses of trace uranium.The influence of H+,Fe3+and NO-3are studied in this paper.The fluorescence intensity of uranyl fluorescent complex is greatly affected by nitric acid.The fluorescence are completely quenched when the concentration of nitric acid is0.075mol/L.The concentration and lifetime of fluorescent complex are reduced by the addition of H+.The fluorescence intensity is also affected by Fe3+and NO-3because of the absorption of exciting light.
引文
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[4]王志麟,谈富星,郑戒法.激光荧光法测定超痕量铀的研究Ⅱ:磷酸及磷酸盐体系中铀的测定[J].核化学与放射化学,1983,5(1):31-37.
[2]Akira K,Takaumi K,Zenko Y,et al.Speciation study on complex formation of uranium(Ⅵ)with phosphate and fluoride at high temperatures and pressures by time-resolved laser-induced fluorescence spectroscopy[J].Radiochim Acta,2004,92:889-896.
[3]Wang Z M,Zachara J M,Wassana Y,et al.Cryogenic laser induced fluorescence characterization of U(Ⅵ)in hanford vadose zone pore waters[J].Environ Sci Technol,2004,38:5591-5597.
[4]王志麟,谈富星,郑戒法.激光荧光法测定超痕量铀的研究Ⅱ:磷酸及磷酸盐体系中铀的测定[J].核化学与放射化学,1983,5(1):31-37.