二甲酚橙分光光度法测定硼砂中的微量铝

目的: 研究二甲酚橙与铝的显色反应体系,建立分光光度法测定硼砂中微量铝的新方法。方法: 在表面活性剂吐温-20存在下,pH 3.0的醋酸-醋酸钠缓冲液介质中,铝与二甲酚橙以1∶1形成稳定的紫红色络合物,在550 nm处测定其吸光度,并计算铝的含量。结果: 铝离子质量浓度在0.3~0.13 mg ·L^-1与吸光度呈良好的线性关系(r=0.998 4);重复性试验RSD为0.83%;加标回收率为98.83%,RSD为2.31%;最低检出量0.032 mg ·L^-1。结论: 该方法简便、快速、显色稳定,适用于硼砂中的微量铝的测定。

Determination of Aluminum in Borax by Xylenol Orange (XO) Spectrophotometric Method

Objective: The color reaction of xylenol orange with aluminum was studied to establish a new quantitative analysis method for aluminum in borax by spectrophotometric method. Method: Aluminum could react with XO to form a stable amaranth complex in HAc-NaAc buffer solution at pH 3.0 in the presence of surfactant Tween 20. The absorption was detected at 550 nm, and aluminum content was calculated. Result: A good linear relationship was obtained between the absorbance and concentration of Al in the range of 0.3-0.13 mg ·L^-1 with the correlation coefficient of 0.998 4, the relative standard deviation(RSD) of the repeat test was 0.83%;the average recovery rate was 98.83% with RSD of 2.31%, the detection limit was 0.032 mg ·L^-1. Conclusion: This method is simple, convenient, quick, and has stable color reaction, so it can be used for the quantitative analysis of aluminum in borax.