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建立了以新合成试剂5-(5-碘-2-吡啶偶氮)-2,4-二氨基甲苯(5-I-PADAT)做显色剂双波长叠加分光光度法测定微量钯的新方法。在0.6～2.4 mol/L HClO4介质中,Pd(II)与5-I-PADAT反应形成1:1蓝紫色络合物,该络合物呈现两个强弱不等的吸收峰,分别位于在584 nm和546 nm,吸光度之和与Pd浓度线性相关。Pd在0～1.2μg/mL范围内符合比尔定律,表观摩尔吸光系数ε584+546=1.18×105L.mol-1.cm-1,较单波长法提高了1.6倍。常见金属离子及125倍的Au和Rh、50倍的Ag、25倍的Ru、12.5倍的Os和Ir、9倍的Pt等贵金属离子均不干扰对钯的测定。该法已应用于分子筛中微量钯的测定。
A new method for the determination of trace palladium with double wavelength superposition spectrophotometry using a new synthetic reagent 5- (5-iodo-2-pyridylazo) -2,4-diaminotoluene (5-I-PADAT) . In 0.6 ~ 2.4 mol / L HClO4 medium, Pd (II) reacted with 5-I-PADAT to form a 1: 1 blue-violet complex, which showed two peaks at different intensities, At 584 nm and 546 nm, the sum of the absorbances is linearly related to the Pd concentration. Beer’s law was obeyed in the range of 0-1.2μg / mL. The apparent molar absorptivity ε584 + 546 = 1.18 × 105L.mol-1.cm-1, which was 1.6 times higher than that of the single-wavelength method. Common metal ions and 125 times of Au and Rh, 50 times of Ag, 25 times of Ru, 12.5 times of Os and Ir, 9 times of Pt and other precious metal ions do not interfere with the determination of palladium. This method has been applied to the determination of trace amounts of palladium in molecular sieves.