光导纤维微量荧光滴定法测定钢中镍

• 作 者: 吕九如 杨秀芳 章竹君
• 机 构: 陕西师范大学化学系微量分析研究室,陕西师范大学化学系微量分析研究室,陕西师范大学化学系微量分析研究室 西安,西安,西安
• 出 处: 冶金分析
• 发表日期: 1986年06期
• 关键词: 光导纤维 钙黄绿素 荧光滴定 试液 滴定法测定 荧光指示剂 滴定终点 反滴定 荧光 荧光性质

钙黄绿素(Calcien)在pH>12的碱性溶液中不产生荧光,而它与钙形成的络合物在此pH下却具有荧光性质(λ_(ex)=490nm且_(em)=520nm)。根据这一现象,我们在自制的多功能光导纤维光度计上建立了钢中镍的微量荧光滴定法。本方法以钙黄绿素为荧光指示剂,以三乙醇胺为掩蔽剂,在强碱性试液中加入过量的EDTA与镍络合,然后用标准钙溶液反滴定过量的EDTA。绘制滴定过程中试液的荧光强度与滴加标准钙溶液体积的关系曲线,确定滴定终点。

Calcien does not generate fluorescence in alkaline solutions at pH> 12, whereas complexes with calcium have fluorescent properties at this pH (λ_ (ex) = 490 nm and _ (em) = 520 nm) . Based on this phenomenon, we have established a micro-fluorescence titration of nickel in steel on a self-made multifunctional optical fiber photometer. The method takes calcein as fluorescence indicator, triethanolamine as masking agent, and adds excess EDTA to nickel in strong alkaline solution, and then back titrates excess EDTA with standard calcium solution. Draw the curve of the fluorescence intensity of the test solution during the titration and the volume of the standard calcium solution added dropwise to determine the end point of the titration.