5-Br-PADAB分光光度法测定钯

Spectrophotometric Determination of Palladium Using 5 Br PADAB

研究了４－（５－溴－２－吡啶偶氮）－１，３－二氨基苯（简称５－Ｂｒ－ＰＡＤＡＢ）分光光度法测定微量钯的反应，在乙酸介质中Ｐｄ（Ⅱ）与５－Ｂｒ－ＰＡＤＡＢ生成紫红色络合物，确定了分光光度法测定钯的新体系。在实验条件下试剂的最大吸收峰位于４３８ｎｍ处，络合物的最大吸收峰位于５６４ｎｍ处，表观摩尔吸光系数ε＝５．２０×１０－４Ｌ／ｍｏｌ．ｃｍ，用等摩尔连续变化法、摩尔比法测得络合比ｎ（Ｐｄ（Ⅱ））∶ｎ（５－Ｂｒ－ＰＡＤＡＢ）＝１∶１，钯离子的量浓度在４．２７×１０－８～１．５４×１０－５ｍｏｌ／Ｌ时，服从Ｂｅｅｒ定律。试验了３０种离子在一定量下不干扰测定。

In this paper,the spectrophotometric determination of Pd(Ⅱ) with 4 [(5 Bromo 2 pyridyl) azo] 1,3 diamino benzene (5 Br PADAB) was studied.The method is based on the reaction of Pd(Ⅱ) with 5 Br PADAB to form a red complex in a medium of HAc and determined in a medium of 0.80mol/L HCl. Maximum absorption of the complex is at 564 nm. The apparent molar absorptivity is 5.20×10 4L·mol -1 ·cm -1 .Beer′s law is obeyed within the range of 4.27×10 -8 ～1.54×10 -5 mol/L.The complex is stablein 24 h. The composition of complex has been found to be 1:1. The method has better sensitivity and selectivity and has been used to determine microamounts of Palladium in an ore. The result is satisfactrory.