【摘要】 研究了新显色剂 2 - ( 2 -咪唑偶氮 ) - 5-二乙氨基苯胺 ( IZAEA)与 Pd2 +显色反应的条件。试验结果表明 ,在 p H5.0的 HOAc- Na OAc介质中 ,试剂与 Pd2 +形成稳定的紫红色络合物 ,此络合物不被强酸分解 ,其它金属离子与试剂形成的有色络合物均被强酸分解。络合物的 λmax为 564nm,试剂的 λmax为 4 76nm,对比度 Δλ为 88nm,Pd2 +与试剂的络合比为 1∶ 2 ,表观摩尔吸光系数为 2 .81× 1 0 4 L·mol- 1 ·cm- 1 ,Pd2 +浓度在 0～ 0 .8mg·L- 1 范围内遵守比耳定律。所拟方法直接测定催化剂和分子筛中微量钯 ,结果满意。更多还原

【Abstract】 In this paper, the optimum conditions for the colour reaction of the new reagent 2 (2 imidazolylazo) 5 diethylamino aniline (abbreviated as IZAEA) with Pd 2+ are reported. It is shown that the new colour reagent reacts with palladium to form a stable purple red complex (mole ratio M∶R=1∶2) in a buffer medium of HOAc NaOAc (pH 5.0), and the complex will not be decomposed by acidifying with some strong mineral acids, e.g. HCl, HNO 3, H 2SO 4 or HClO 4, while complexes formed by other co existing ions and IZAEA will be decomposed, thus the selectivity is improved. The apparent molar absorptivity and the absorption maxima are found to be 2.81×10 4L·mol -1 ·cm -1 and 564nm. Beer′s law is obeyed in the range of 0~0.8mg·L -1 for Pd 2+ . The method has been used for the direct determination of palladium in Pd containing calalyst and molecular sieve with satisfactory results.更多还原