管式炉加热-红外吸收法测定铀金属中碳

Determination of carbon in uranium metals by tubular furnace heating-infrared absorption method

称取100mg处理后试样,选取加热温度为850℃,建立了管式炉加热红外吸收法测定铀金属中微量碳的方法。试验表明：将金属铀切屑试样用硝酸（1＋1）加热至微沸并保持2min,取出后再依次用水、丙酮、无水乙醇漂洗可有效去除金属铀切屑样品表面的碳沾污。以蔗糖作为校准标样,碳量在0-12.5μg之间线性相关系数（r）为0.999 8。方法空白值为2.4μg/g,测定下限为5μg/g。按照实验方法对铀金属材料中碳进行测定,结果的相对标准偏差（RSD,n=3）为4.3%-6.1%,加标回收率为100%。应用于铀金属材料中碳含量的测定,结果与高频燃烧-红外吸收法一致。

A tubular furnace heating-infrared absorption method for the determination of micro carbon in u ranium metals was established with 100 mg of pre-treated sample at 850 ℃. Experiment showed that ： after the uranium metal sample chips were heated to micro-boiling for 2 min with HNO3 （1 ＋1） and rinsed by water, acetone and absolute ethyl alcohol in sequence, the carbon contamination on the sample surface could be effectively eliminated. With sucrose as calibration sample, the linear correlation coefficient （r） was 0. 999 8 with carbon amount in the range of 0-12.5 μg. The blank value was 2.4μg/g, and the limit of quantification was 5 μg/g. When carbon in uranium metal materials was determined by proposed method, the relative standard deviation （RSD, n = 3） was 4. 3%- 6. 1% and the standard addition recovery was 100%. The determination results were consistent with those of high frequency combustion-infrared ab sorption method.