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目的研究采用不同的土壤预处理方法联合电感耦合等离子体质谱(ICP-MS)技术,同时分析土壤中铀含量及235U/238U比值的方法,并且分析我国9种典型土壤中的铀含量及235U/238U比值。方法分别采用微波消解、灰化法和直接酸溶法对土壤样品进行预处理,通过ICP-MS同时测定土壤中的铀含量和235U/238U。采用建立的方法分析我国9种土壤中的铀含量及235U/238U。结果铀元素在0～400μg/kg线性良好(r=0.9999),精密度较高(RSD为0.11%～2.37%)。土壤样品预处理方法中,以HNO3+HF+H2O2为消解试剂进行微波消解得到的结果与推荐值吻合较好(相对误差为5.2%),土壤中铀回收率为100.6～109.0%,最低检测限为0.86 ng/kg。我国9种土壤中的铀浓度为1.2～4.0 mg/kg,各种土壤中的235U/238U均接近天然水平(0.00 725)。结论本研究建立了微波消解与ICP-MS联合应用,同时分析土壤中的铀含量及235U/238U的方法,该方法线性范围宽、准确度高、检测限低,采用该方法检测的我国9种土壤中的铀含量和235U/238U均在正常水平。
OBJECTIVE To study the method of simultaneous determination of uranium and 235U / 238U in soils using different soil pretreatment methods combined with inductively-coupled plasma mass spectrometry (ICP-MS), and to analyze the uranium content in 235 soil samples and 235 U / 238U ratio. Methods The soil samples were pretreated by microwave digestion, ashing and direct acid-solubilization respectively. The contents of uranium in the soil and 235U / 238U were simultaneously determined by ICP-MS. Uranium content in 9 soils of our country and 235U / 238U were analyzed by established method. Results The results showed that the uranium content was linear at 0 ~ 400 μg / kg (r = 0.9999) and the precision was high (RSD 0.11% ~ 2.37%). In the soil sample pretreatment method, the result of microwave digestion with HNO3 + HF + H2O2 as digestion reagent was in good agreement with the recommended value (relative error was 5.2%), the recovery rate of uranium in soil was 100.6-109.0%, and the lowest detection limit 0.86 ng / kg. Uranium concentrations in nine soils in China ranged from 1.2 to 4.0 mg / kg, and 235 U / 238 U in various soils were close to their natural level (0.00 725). Conclusion This study established a microwave digestion combined with ICP-MS, while the analysis of soil uranium content and 235U / 238U method, the linear range of this method, high accuracy, low detection limit, using this method to detect nine kinds of our country Uranium content in the soil and 235U / 238U are at normal levels.