Byrne A R, Benedik L
"J. Stefan" Institute, "E. Kardelj" University, 61000 Ljubljana, Yugoslavia.
Talanta. 1988 Mar;35(3):161-6. doi: 10.1016/0039-9140(88)80058-4.
Nanogram and picogram quantities of uranium were determined in biological materials by radiochemical neutron-activation analysis. Two different approaches using either (239)U or (239)Np were employed for cross-checking, and the question of negative errors due to incomplete acid dissolution of any possible inorganic (siliceous) fraction was studied. In the first and main approach, radiochemical separation of the short-lived (239)U (23.5 min) nuclide was based on TBP extraction following rapid conventional wet-ashing. Addition of large amounts of uranium carrier (ca. 50 mg) allowed the chemical yield to be evaluated from the gamma spectrum of the isolated fraction by means of the 186 keV peak of (235)U. In the second approach, the longer-lived (239)Np (56.5 hr) daughter was separated by anion-exchange; this nuclide allowed use of lengthier dissolution procedures employing total decomposition with hydrofluoric acid. Nanogram quantities of (237)Np were irradiated simultaneously with the sample and an aliquot of the resulting solution containing (237)Np and (238)Np (51 hr) was added prior to sample destruction, these isotopes serving as carrier and yield tracer, respectively. Results are presented for a series of reference materials. The methodologies and results from the two approaches are discussed and evaluated.
采用放射化学中子活化分析法测定生物材料中纳克和皮克数量级的铀。使用（239）U或（239）Np的两种不同方法进行交叉核对，并研究了由于任何可能的无机（硅质）部分酸溶解不完全而导致负误差的问题。在第一种也是主要的方法中，短寿命（239）U（23.5分钟）核素的放射化学分离基于快速常规湿灰化后的TBP萃取。加入大量铀载体（约50毫克）后，可通过（235）U的186 keV峰，从分离部分的γ能谱评估化学产率。在第二种方法中，通过阴离子交换分离寿命较长的（239）Np（56.5小时）子体；这种核素允许使用更长的溶解程序，采用氢氟酸全分解。将纳克数量级的（237）Np与样品同时辐照，并在样品破坏前加入含有（237）Np和（238）Np（51小时）的所得溶液的一份等分试样，这些同位素分别用作载体和产率示踪剂。给出了一系列参考材料的结果。对两种方法的方法和结果进行了讨论和评估。
