对-偶氮苯重氮氨基偶氮苯磺酸与钯的显色反应研究及其应用

Color Reaction of Palladium With β-Azobenzenediazoaminoazobenzene Sulfonic Acid and Its Application

本文研究了对-偶氮苯重氮氨基偶氮苯磺酸在非离子表面活性剂Tween-80存在下,与钯(Ⅱ)显色反应适宜条件.实验结果表明,在pH10.80～11.10范围内钯(Ⅱ)与题示试剂形成1:4的橙红色络合物,其最大吸收峰位于533nm处,试剂最大吸收为440nm,其对比度达93nm.钯(Ⅱ)在0～30μg/25ml范围内遵守比耳定律,并由此计算出其表观摩尔吸光系数ε_(533)=1.0×10~5L.mol^(-1).cm^(-1)。该方法用于催化剂中微量钯的测定,获得了令人满意的结果。

A highly sensitive spectrophotometric method has been developed for the determination of palladium with p-azobenzenediazoaminoazobenzene sulfonic acid (ADAAS) in the presence of non-ionic surfactant Tween-80. The color reaction of this orange-red complex is developed in the NaH2PO4-Na2HPO4 solution at pH 11. 0. Its apparent molar absorptivity is 1. 0×105 L. mol-1. cm-1at 533 nm. Beer's law is obeyed in the range of 0-30 μg Pd(Ⅰ)/15 ml. The molar ratio of Pd(Ⅰ)to ADAAS in the complex has been estimated to be 1 : 4. The color of aqueous solution is stable for at least 12 h. Sodium fluoride has been used to increase the selectitity of the method. The recommended method has been used for the determination of palladium in catalyst sample with satisfactory results.