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钯的测定以前大多用丁二肟重量法。但操作繁冗,在分析高含量钯时引入较大误差,因此我们分别使用二种容量法(一)电位滴定法(二)络合滴定法来测定钯希土合金中钯含量,结果与重量法相符。它们的特点是简单、快速、便于推广。电位滴定法钯(Ⅱ)与碘离子作用,生成溶解度很小的碘化钯沉淀(25℃时K_(SP)=1.4×10~(-18)),在pH2～5范围内,用碘电极或氰电极(AgI基)指示,以碘化钾溶液滴定钯(Ⅱ),终点时有十分明显的电位突跃,可直接滴定5×10~(-6)M～1×10~(-2)M钯,相应变动系数为6%～0.13%。在酸性条件下,对碘电极(或氰电极)有干扰
Most of the previous determination of palladium with diazoxide gravimetric method. However, the operation is cumbersome, and large errors are introduced when analyzing high content of palladium. Therefore, we use two kinds of volumetric method (a) potentiometric titration (b) complexometric titration to determine palladium content in palladium-loyer alloy. Results and weight method Match. Their characteristics are simple, fast and easy to promote. Potentiometric titration of palladium (Ⅱ) with iodide ion to produce a very small solubility of palladium iodide precipitation (25 ℃, K_ (SP) = 1.4 × 10 ~ (-18)), in the pH range 2 ~ 5 with iodine electrode (AgI-based) or titration of palladium (II) with potassium iodide solution. At the end of the titration, there is a very clear potential jump and titration of 5 × 10 -6 M -1 × 10 -2 M Palladium, the corresponding coefficient of variation of 6% to 0.13%. Under acidic conditions, there is interference with iodine (or cyanide) electrodes