Godoy Maria Luiza D P, Godoy José Marcus, Kowsmann Renato, Dos Santos Guaciara M, Petinatti da Cruz Rosana
Instituto de Radioproteção e Dosimetria, Comissão de Energia Nuclear, Caixa Postal 37750, Barra da Tijuca, CEP 22643-970, Rio de Janeiro, RJ, Brazil.
J Environ Radioact. 2006;88(2):109-17. doi: 10.1016/j.jenvrad.2005.12.012. Epub 2006 Mar 20.
A 234U and 230Th determination method based on an extraction chromatographic separation on a flow injection system coupled to a quadruple ICP-MS was developed. Two-milliliter UTEVA (Eichrom Co.) cartridges were applied as separation tool and 236U and 229Th as spikes. Loading and washing steps were carried out in 3 M HNO3 solution and 0.05 M ammonium oxalate applied to elute both uranium and thorium. The method was applied initially to the IAEA-327 soil reference sample and NIST SRM 4357 ocean sediment reference material, with the obtained 234U and 230Th concentrations in agreement with the reference levels. Samples from a deep-sea sediment core (2450 m water depth) were analyzed and based on 230Th/234U dating, a mean sedimentation rate of 3.3 cm ky(-1) was calculated. Samples from two sediment layers were also dated by 14C-AMS and the observed ages agree with the 230Th/234U results.
开发了一种基于流动注射系统与四极杆电感耦合等离子体质谱联用的萃取色谱分离法测定234U和230Th。采用2毫升UTEVA（艾克龙公司）柱作为分离工具，以236U和229Th作为示踪剂。在3M硝酸溶液中进行加载和洗涤步骤，并用0.05M草酸铵洗脱铀和钍。该方法最初应用于国际原子能机构-327土壤标准样品和美国国家标准与技术研究院SRM 4357海洋沉积物标准物质，所得234U和230Th浓度与参考水平一致。对取自深海沉积物岩芯（水深2450米）的样品进行了分析，并基于230Th/234U测年法计算出平均沉积速率为3.3厘米/千年（-1）。还通过14C-AMS对两个沉积层的样品进行了测年，观测到的年龄与230Th/234U结果一致。
