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用2-吡啶偶氮类衍生物分光光度法测定微量钴,虽然灵敏度高,但钯的干扰较严重,至今尚未见简单的消除方法。本文采用5-[(5-氯2-吡啶)偶氮]-2,4-氨基甲苯(简称5-Cl-PADAT)作显色剂,提出利用差减法消除测定钴时钯的干扰,以及钴、钯同时测定的新方法。在实验条件下,钴和钯与试剂分别形成1:2和1:1的紫红色配合物。配合物的最大吸收波长在570nm处,摩尔吸光系数ε_(Co)=1.20×10~5,ε_(Pd)=6.90×10~4。钴浓度在0～10μg/25mL,钯浓度在0～25μg/25mL时符合Beer定律。该法灵敏度高,选择性好,手续简单,快速,用于钯精矿,钢样及分子筛中微量钴和钯的同时测定,获得了良好的结果。
Spectrophotometric determination of trace cobalt with 2-pyridine azo derivatives has high sensitivity, but the interference of palladium is more serious. So far no simple elimination method has been found. In this paper, the use of 5 - [(5-chloro-2-pyridyl) azo] -2,4-aminotoluene (referred to as 5-Cl-PADAT) as a developer, proposed the use of subtractive subtractive method to eliminate the palladium interference when cobalt, , A new method for the simultaneous determination of palladium. Under the experimental conditions, cobalt and palladium form a purple complex with 1: 2 and 1: 1 respectively with the reagents. The maximum absorption wavelength of the complex at 570nm, the molar absorption coefficient ε Co = 1.20 × 10 ~ 5, ε Pd = 6.90 × 10 ~ 4. The Beer’s law was obeyed when cobalt concentration was 0 ~ 10μg / 25mL and palladium concentration was 0 ~ 25μg / 25mL. The method has high sensitivity, good selectivity, simple and rapid procedure, and is used for the simultaneous determination of trace amounts of cobalt and palladium in palladium concentrates, steel samples and molecular sieves, and obtains good results.