Verma Poonam, Rastogi Ramakant K, Ramakumar Karanam L
Radioanalytical Chemistry Section, Radiochemistry and Isotope Group, Bhabha Atomic Research Centre, Mumbai 400085, India.
Anal Chim Acta. 2007 Jul 23;596(2):281-4. doi: 10.1016/j.aca.2007.06.019. Epub 2007 Jun 16.
A simple, sensitive and fast ion chromatographic (IC) method with suppressed conductivity detection is described for the determination of traces of nitrogen in uranium based fuel materials. Initially a method was developed to determine nitrogen as NH4(+) using cation exchange column after matrix separation by Kjeldahl distillation. The method was then improved by eliminating this distillation. Matrix separation after sample dissolution was done by hydrolyzing and filtering off the polyvalent cations. This had helped in reducing both the sample size and analysis time. Optimization of dissolution conditions for various kinds of uranium based samples was done to keep acid content minimum; a prerequisite chromatographic condition. The calibration plot for nitrogen was linear in the concentration range of 0.02-1 mg L(-1) with regression coefficient of 0.9999. The relative standard deviation (R.S.D.) obtained in this method (100 microL injected) was 3% and 2% in 9 replicates at nitrogen level of 28 and 55 ng g(-1), respectively. Detection limit based on S/N=3 (100 microL injected) as well as three times of variation in blank value was 4 ng g(-1). The developed method was authenticated by comparison with certified uranium-alloy standard as well as with independent indophenol photometry method. The developed method was applied to uranium-alloy, uranium-metal, sintered UO2 pellets and sintered UO2 microspheres samples.
本文描述了一种采用抑制型电导检测的简单、灵敏且快速的离子色谱（IC）方法，用于测定铀基燃料材料中的痕量氮。最初开发了一种方法，通过凯氏蒸馏进行基体分离后，使用阳离子交换柱将氮测定为NH4(+)。随后通过省去该蒸馏步骤对方法进行了改进。样品溶解后的基体分离是通过水解并滤除多价阳离子来完成的。这有助于减小样品量并缩短分析时间。对各种铀基样品的溶解条件进行了优化，以使酸含量保持最低，这是色谱分析的一个前提条件。氮的校准曲线在0.02 - 1 mg L(-1)浓度范围内呈线性，回归系数为0.9999。在该方法中（进样100 μL），在氮含量为28和５5 ng g(-1)时，9次重复测定得到的相对标准偏差（R.S.D.）分别为3%和2%。基于S/N = 3（进样100 μL）以及空白值三倍变化的检测限为4 ng g(-1)。通过与认证的铀合金标准物质以及独立的靛酚光度法进行比较，对所开发的方法进行了验证。所开发的方法应用于铀合金、金属铀、烧结UO2颗粒和烧结UO2微球样品。
