激光荧光法测定天然水和土壤中痕量铀

DETERMINATION OF TRACE URANIUM IN NATURAL WATER AND SOIL BY LASER-INDUCED FLUORESCENCE SPECTROMETRY

利用氮分子激光器及激光光度仪,进行了激光荧光法测定痕量铀的研究。在实验中采用了波长色散技术及时间分辨技术。在荧光增强剂中加入CyDTA等络合剂后,使测定铀的灵敏度及选择性都优越于加拿大专利试剂Fluran。方法的检测下限为0.01ppb铀。 利用5209萃淋树脂分离铀并对土壤中铀的测定进行了研究。10~5～10~7倍量的杂质元素的存在不影响铀的测定。 采用本方法做了天然水及土壤中铀的样品。与其他化学法对照,所取得的结果是满意的。

The determination of trace uranium in the fluorescence-enhancing agent which consists mainly of sodium pyrophosphate by measuring the laser-induced fluorescence of uranyl ions with a nitrogen laser and a Boxcar integrator has been investigated.Both the wavelength dispersive technique and the time-resolved technique Were used. By addition of CyDTA in the fluorescence-enhancing agent, the sensitivity and selection of determination of trace uranium are better than "Fluran" agent and that by addition of EDTA. The trace uranium in natural water without separation of the foreign ions and precon-centration of uranium was determined. It was shown that the detection limit was 0.1 ppb U and the precision Was better than±5% at 0.4 ppb U level. The investigation on separation of uranium from the foreign ions by the levextrel resin 5209 and the determination of trace uranium in soil using the described method were developed and reported. This method can be used for samples containing a great quantity of interfering species.