3.5-diCl-DMPAP与镉显色反应的研究

Spectrophotometric Study on the Colour Reaction of Cd with 3,5-diCl-DMPAP

研究了2-[3,5-二氯-2-吡啶)偶氮]-5-二甲氨基酚,在不同表面活性剂和混合表面活性剂的存在下,与镉离子的显色反应。实验结果表明,在非离子表面活性剂Tritonx-100存在下,3.5-diCl-DMPAP与镉在pH7.4～10范围内,形成1:2的红紫色配合物,试剂的最大吸收波长为447.4nm,配合物的最大吸收波长为567.4nm,ε_(567.4)=1.15×10~5。比耳定律适用范固为0～12μg/25mL,该方法用于含镉废水中微量镉的测定,获得满意结果。

The colour reaction of Cd with 2-[(3,5-diCl-2-pyridyl)azo]-5-dimethyl-aminophenol (3,5-diCl-DMPAP)in the presence of various surfaetants or mixed surfactants has been studied. The experimental results show that in the presence of nonionic surfactant TritonX-100, 3, 5-diCl-DMPAP reacts with Cd at pH=7.5～10 yielding a 1:2 purple red colouredcomplex which has a maximum absorbance at 567nm. The apparent molar absorptivity is 1.15×10~5. Beer's Law is obeyed for 0～12μg/25mL. This method has been successfully used for the determination of trace Cd in samples.