Tween 20增敏二甲酚橙分光光度法测定水中痕量铝

Spectrophotometric determination of trace aluminum in water with xylenol orange based on sensitivity-enhancing effect of Tween 20

研究了表面活性剂吐温20（Tween20）对二甲酚橙（X0）与铝显色反应的增敏作用，建立了分光光度法测定水中痕量铝的新方法。实验结果表明，在HAc-NaAc介质中，铝与二甲酚橙、吐温20反应生成的有色络合物，最大吸收波长为510nm，表观摩尔吸光系数ε为2.63×10^4L·mol^-1·cm^-1，铝的质量浓度在0-0.64μg／mL范围内与吸光度呈良好的线性关系，相关系数r=0.9987，检出限为0.0077μg／mL。方法应用于管网水和河水中铝的测定，相对标准偏差为1.2％-1.7％，回收率在97％-103％范围。

The sensitivity-enhancing effect of Tween 20 on the color reaction of xylenol orange （XO） with copper was studied to establish a novel speetrophotometric determination method of trace aluminium in water. The results showed that a stable colored complex was formed by the reaction among Al, XO and Tween 20 in HAc-NaAc buffer solution. The maximum absorption wavelength of this complex was at 510 nm and the apparent molar absorptivity was 2.63×10^4L·mol^-1·cm^-1. A good linear relationship was obtained between the absorbance and concentration of Al in the range of 0-0.64μg/mL with the correlation coefficient of 0.9987. The detection limit was 0.0077μg/mL. The proposed method has been applied to the determination of AI in tap water and river water samples, with the relative standard deviation （RSD） of 1.2 %-1.7% and the recovery of 97%-103%.