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该文叙述了用涂有三辛基氧化膦(简称TOPO)的玻态碳电极(简称GC电极)伏安法测定铀化工废液中痕量铀。在测定之前,将UO_2~(2+)预先浓集在GC电极的TOPO涂层上。为此将2.5μL的TOPO酒精溶液(1.5×10~(-2)mol/L)加到GC电极的圆形(直径约7mm)截面上, 然后用红外灯烘熔,形成均匀的膜。这种电极,在开路状况下能有效地从溶液(0.25mol/LKNO_3,pH3.4)中选择地浓集痕量UO_2~(2+)。被浓集的UO_2~(2+)在-0.35V(对甘汞电极)处产生一还原波,波高与溶液中UO_2~(2+)的浓度存在着依赖关系。该方法对UO_2~(2+)具有很高的选择性,因为TOPO涂层能阻挡其它在没有这种涂层的电极上能产生还原波的一些离子。该方法还具有灵敏度高、简单、快速等优点。
This paper describes the determination of trace uranium in uranium chemical waste by voltammetry using glassy carbon electrode coated with trioctylphosphine oxide (abbreviated as TOPO). Prior to the measurement, UO 2 2+ was pre-concentrated on the TOPO coating of the GC electrode. To this end, 2.5 μL of TOPO alcohol solution (1.5 × 10 -2 mol / L) was added to the circular (about 7 mm diameter) section of the GC electrode and baked with an infrared lamp to form a uniform film. This electrode, in the open-circuit condition, effectively concentrates traces of UO 2 2+ from solution (0.25 mol / L KNO 3, pH 3.4). The concentration of UO_2 ~ 2 produced a reduction wave at -0.35V (for calomel electrode), and the wave height was dependent on the concentration of UO_2 ~ (2+) in the solution. This method is highly selective for UO 2 2+ since the TOPO coating blocks some of the other ions that produce reducing waves at the electrode without this coating. The method also has the advantages of high sensitivity, simple, fast and so on.