百里香酚蓝分光光度法测定铝合金中钛

Determination of titanium in aluminum alloy by thymol blue spectrophotometry

采用氢氧化钠溶液和双氧水溶解样品,加入酒石酸钾钠溶液消除Fe^(3+)的干扰,加入硫脲溶液提高Cu^(2+)的允许量,在稀硫酸介质中,增敏剂阿拉伯树胶存在下,钛与显色剂百里香酚蓝发生反应形成稳定的蓝紫色络合物,建立了百里香酚蓝分光光度法测定铝合金中钛的方法。结果表明:络合物最大吸收峰位于590nm,溶液中钛质量浓度在0.1～2μg/mL范围内符合比尔定律,方法检出限为0.03μg/mL,表观摩尔吸光系数为3.7×10~4 L·mol^(-1)·cm^(-1)。方法用于铝合金标准样品中钛含量的测定,测定值与认定值基本一致,钛测定结果的相对标准偏差(RSD,n=6)为2.3%和3.4%。

The sample was dissolved with sodium hydroxide solution and hydrogen peroxide.Potassium sodium tartrate solution was added to eliminate the interference of Fe^3+.Thiourea solution was added to increase the tolerant amount of Cu^2+.In diluted sulfuric acid medium,titanium could react with chromogenic reagent of thymol blue to form stable and blue purple complex in presence of sensitizer of arabic gum.Consequently,a determination method of titanium in aluminum alloy by thymol blue spectrophotometry was established.The results showed that the maximum absorption peak of complex located at590nm.The Beer′s law was obeyed for the mass concentration of titanium in range of0.1-2μg/mL.The detection limit of method was0.03μg/mL.The apparent molar absorptivity was3.7×10^4L·mol^-1·cm^-1.The proposed method was applied for determination of titanium in certified reference material of aluminum alloy.The results were basically consistent with the certified values.The relative standard deviations(RSD,n=6)of determination results were between2.3%and3.4%.