2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺吸光光度法测定痕量镍的研究

Study on determination of trace nickel by spectrophotometry using 2-(5-bromo-2-pyridylazo)-5-dimethylaminoaniline

本文以SDS为表面活性剂,以5-Br-PADMA为显色剂,在pH值为5.0～6.5的HAc-NaAc缓冲体系中,5-Br-PADMA能够与Ni(Ⅱ)形成稳定的橙红色配合物,其最大吸收波长位于574 nm处,摩尔吸光系数为4.52×10^(5 )L·(mol·cm)^(-1),形成的配合物中,Ni^(2+)的浓度在0～4μg/10mL的范围内符合比尔定律。在一定含量的焦磷酸钠、NH_4Cl和硫脲的存在下,该方法具有良好的选择性和稳定性。方法用于陕南镍矿矿样中痕量镍的测定,结果与参考值相符。

This paper with SDS as surfactant and 5-Br-PADMA as a chromogenic agent, at pH is 5.0-6.5 HAc-NaAc buffer solution, 5-Br-PADMA can form a stable orangecomplex with Ni （ Ⅱ ）, the maximum absorption wavelength in 574, molar absorption coefficient of light 4.52 ×10 5 L· （mol·cm）-1, Ni （ Ⅱ ） concentration in the oral administration in the range of 0- 4 μg/10mL form the Lambert law. In the presence of a certain amount of sodium pyrophosphate,ammonium fluoride and thiourea.The method has good selectivity and stability can be used for the determination of trace amounts of nickel in ores, the results was consistent with the reference values.