新试剂偶氮胂HCS用于海产品中微量钍的测定

PHOTOMETRIC DETERMINATION OF THORIUM IN SEAFOOD WITH A NEW REAGENT ARSENAZO-HCS

研究了新试剂 2 (2 胂酸基苯偶氮 ) 7 (2 羟基 3 羧基 磺酸苯偶氮 ) 1,8 二羟基 3,6 萘二磺酸 (简写作偶氮胂HCS)与钍的显色反应 ,建立了一种测定海产品中微量钍的光度法。在3 0mol·L-1硝酸介质中 ,钍与偶氮胂HCS发生灵敏的显色反应 ,生成 1∶2的绿色配合物。该配合物的吸收峰位于 676nm ,表观摩尔吸光系数为 8.5 4× 10 4 L·mol-1·cm-1。钍含量在 0～ 30 μg 2 5ml符合比耳定律。由于偶氮胂HCS水溶性非常好 ,可在高酸性条件下反应 ,使显色反应有极佳的选择性 ,大量的常见金属离子以及铀、稀土不干扰微量钍的测定 。

A new chromogenic reagent, 2 (2 arsonophenylazo) 7 (2 hydroxy 3 carboxyl 5 sulfophenylazo) 1,8 dihydroxynaphthalene 3,6 disulfonic acid (abbreviated as arsenazo HCS) was used in the photometric determination of thorium in seafood. In a 3.0mol·L -1 nitric acid medium, Th(Ⅳ) reacts with arsenazo HCS to form a blue complex (mole ratio 1∶2) having its absorption maxima at 676nm, and an apparent molar absorptivity of 8.54×10 4. Beer′s law is obeyed in the concentration range of 0～30μg of Th(Ⅳ) in 25ml of solution. Most of common co existing ions, especially uranium and rare earth elements, did not interfere with the determination.