摘要
本文详细研究了新有机试剂2-(2-苯并噻唑偶氮)-5-磺丙氨基苯酚(BTASPAP)与镍(Ⅱ)的水相显色反应.Ni(Ⅱ)与BTASPAP在pH3.5～6.5范围内形成稳定的、易溶于水的、带负电荷的1:2红色配合物,其表观稳定常数为1.99×10~9(20℃,μ0.1),吸收光谱的λ_(max)为550nm,对比度高达105nm,表观摩尔吸光系数ε_(550)为3.40×10~4L·mol^(-1)·cm^(-1)。建议了配合物的结构。在0-36μgNi(Ⅱ)/25ml范围内遵从比耳定律。加入硫脲作掩蔽剂和用NH_3-NH_4CI预分离干扰元素可提高方法的选择性。本法简便、快速、准确可靠,已成功地用于合金钢中痕量镍的测定。
The chromogenic reaction of 2-(2-benzothiazolylazo)-5-(3-sulfopropyl) aminophenol(BTASPAP), a new organic reagent, with Ni(Ⅱ) in the aqueous solution was thoroughly studied. Ni(Ⅱ) reacts with BTASPAP to form a stable, water-soluble, negatively charged, red complex with the composition ratio of 1: 2 and the apparent stability constant of 1.99×10~9(20℃, μ0.1) in the pH range of 3.5 to 6.5. The complex has the absorption spectrum with the λ_(max)550nm, the large contras(Δλ) 105nm and the apparent molar absorptivity ε_(550)3.40×10~4L·mo1^(-1)·cm^(-1). The structrue of the complex was suggested. Beer's law is obeyed in the range of 0 to 36μg of Ni(Ⅱ) per 25ml. The selectivity of the method may be increased by addition of thiocarbamide as masking reagent and pre-separation of the interferential elements using NH_3-NH_4Cl. This method is simple, rapid and accurate. Satisfactory results have been achieved in applying the method to determination of traces of nickel in alloy steel.
关键词
BTASPAP
镍
分光光度法
显色反应
2-(2-benzothiazolylazo)-5-(3-sulfopropyl)aminophenol,nickel,spectro-photometry.
