安替吡啉偶氮分光光度法测定铌

合成了5-(4-安替吡啉偶氮)水杨醛(AASA),探讨了试剂与铌的显色反应条件,建立了测定铌的光度分析新方法。实验表明,在pH 2.0的HCl-KCl缓冲体系中,铌与AASA形成摩尔比为1∶1的浅黄色络合物,最大吸收波长为460 nm。铌 的质量浓度在0～1.6 μg/mL符合比尔定律,其回归方程为A=0.077 79+0.012 91ρ_Nb(μg/25 mL),相关系数r＝0.999 6,表观摩尔吸光系数为3.0×10⁴ L·mol^－1·cm^-1。将AASA分光光度法应用于铁-铌合成溶液中铌的测定,结果与氯磺酚S法一致,相对标准偏差为1.6%～1.7%。

Determination of niobium by antipyrinylazo spectrophotometry

5-(4-antipyrinylazo) salicylaldehyde (AASA) were synthesized,and the conditions for its chromogenic reaction with niobium were investigated. Thus,a novel method for the determination of niobium was established by spectrophotometry. The experimental results showed that niobium and AASA could form a pale yellow complex with molar ratio of 1∶1 and maximum absorption wavelength of 460 nm in pH 2.0 HCl-KCl buffer solution. Beer’s Law was complied within the concentration range of 0-1.6 μg/mL for niobium with linear regression equation of A=0.077 79+0.012 91ρ_Nb(μg/25 mL) and r of 0.999 6,and the apparent molar absorptivity was 3.0×10⁴ L· mol^－1· cm^－1. AASA spectrophotometry was applied to the determination of niobium in iron-niobium synthetic solution,and the results were consistent with those obtained by sulfochlorophenol S method with relative standard deviation of 1.6%-1.7%.