2-(H-酸偶氮)-4,5-二硝基苯酚与钍的显色反应研究及其应用

STUDY ON THE COLOR REACTION OF THORIUM(Ⅵ) WITH THE NEW REAGENT 5-(2-HYDROXY-4,5-DINITROPHENYLAZO)-4-HYDROXY-2,7- NAPHTHALENE DISULFONIC ACID AND ITS APPLICATION

研究了 2 (H 酸偶氮 ) 4 ,5二硝基苯酚 (HADNP)与钍的显色反应 ,在 pH 5 .5HOAc NaOAc缓冲介质中 ,溴化十六烷基吡啶 (CPB)存在下 ,HADNP与钍反应生成 2∶1稳定紫红色络合物 ,λmax=6 2 0nm ,ε =1.2 3× 10 5L·mol- 1·cm- 1。钍含量在 0～ 30 μg/2 5ml内符合比耳定律 ,方法用于环境水样品中钍含量的测定 ,结果满意。

It was found that thorium(Ⅵ) reacts with the new reagent, 5 (2 hydroxy 4,5 dinitrophenylazo) 4 hydroxy 2,7 naphthalene disulfonic acid (HADNP) in the presence of CPB and in an acetate buffer medium of pH 5.5 to form a stable reddish violet complex with its mole ratio Me∶R=1∶2. The molar absorptivity is found to be 1.23×10 5L·mol -1 ·cm -1 . Beer′s law is obeyed in the range of 0～30μg of Th(Ⅵ) per 25ml of solution. This method has been applied to the determination of thorium in water with satisfactory results.