铝-二甲酚橙-吐温20三元体系光度法测定铝

Spectrophotometric Determination of Aluminium with Aluminium-xylenol Orange-Tween 20 System

研究了吐温20（Tween20）存在下,铝与二甲酚橙（XO）的显色反应,建立了分光光度法测定微量铝的新方法。结果表明,在pH=3.13的乙酸-乙酸钠缓冲介质中,铝与XO及吐温20反应生成有色络合物,络合物的最大吸收波长位于511 nm处,表观摩尔吸光系数ε为1.99×10^4L.mol^-1.cm^-1,在10 mL溶液中,铝量在2.2-15.1μg范围内符合比耳定律,检出限为0.0018μg/mL。方法应用于茶叶、沙棘叶中铝的测定,样品加标回收率为96%-102.6%。

A new method for the determination of trace amounts of aluminium was established.The method was based on the color reaction of xylenol orange（XO） with aluminium in the presence of Tween 20.The results indicate that XO could react with aluminium to form a stable colored complex in HAc-NaAc buffer solution at pH=3.13.The maximum absorption wavelength is at 511 nm and the apparent molar absorptivity is 1.99×10^4 L·mol^-1·cm^-1.Beer s law is obeyed in the range of 2.2～15.1 μg for aluminium in 10 mL solution.The detection limit is 0. 0018 μg/mL. The method has been applied to the determination of trace aluminium in tea and sea-buckthorn leaves with the recovery of 96%- 102.6%.