Tween 20增敏二甲酚橙分光光度法测定水中痕量铝

研究了表面活性剂吐温20(Tween 20)对二甲酚橙(XO)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2.63×104L.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=0.998 7,检出限为0.007 7μg/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。

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

The sensitivity-enhancing effect of Tween 20 on the color reaction of xylenol orange (XO) with copper was studied to establish a novel spectrophotometric 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 × 10~4 L·mol~(-1) · cm~(-1). A good linear relationship was obtained between the absorbance and concentration of Al in the range of 0 - 0. 64 μg/mL with the correlation coefficient of 0. 998 7. The detection limit was 0. 007 7 μg/mL. The proposed method has been applied to the determination of Al in tap water and river water samples, with the relative standard deviation (RSD) of 1. 2 % - 1. 7 % and the recovery of 97 % -103 %.