二甲酚橙速差光度法测定废水中铬铁离子

Differential Speed Spectrophotometirc Determination of Fe(3+) and Cr(3+) Ions in Sewage with Xylenol Orange(XO)

研究了Gr(Ⅲ)、Fc(Ⅲ)与二甲酚橙等显色剂络合反应的A～t行为。铁、铬与二甲酚橙等显色剂作用形成的两种络合物具有相似的吸光特性,但生成速率有显著差异,而两者的A～t曲线重现性良好。据此,本文提出了利用速差动力学分析法同时测定铬铁二元混合物的分析方法,并测定了废水实样。本法线性范围:0～0.15g/l,回收率95％～104％。检出下限1mg/l。另外,研究发现茜素红S-铁络合物的工作曲线严重下弯,铬天青S-铁络合物的A～t曲线重现性不良。

The article studies the A-t kinetics activity that takes place during the process of reac- tion of Cr(3+) and Fe(3+) ions with XO and other colorants two complex compounds de- rived from the reaction of Fe(3+) and Cr(3+) with XO and other colorants have similar light absorbance, but their speeds of reaction are obviously different while the repeatability of their A-t curves is satisfactory. Accordingly, a new differential speed kenetics analysis has been developed, with which the bimixture of Fe(3+) and Cr(3+) is determined simaltaneously. The result is satisfactory when it is used in the determination of sample sewage. Linerity 0-0.25 g/1, Recovery 95-104%, Detectionlimit 1 mg/1. Besides, it has been found in the experiments that A-t curves of alizarin red S bend down sharply and the repeatability of the A-t curves of alizarin red S bend down sharply and the repeatability of the A-t curves of chrome azurol S in its reaction with Fe(3+) is not satisfactory.