阻抑溴酚蓝褪色动力学光度法测定痕量钛(Ⅳ)  

Determination of trace titanium(Ⅳ) by kinetic spectrophotometry based on the inhibitory fading reaction of bromophenol blue

作　　者：黎国兰[1] 魏成富[1] 王洪福[1] 罗娅君[1] 李松[1] 

机构地区：[1]绵阳师范学院化学与化学工程学院,四川绵阳621000

出　　处：《冶金分析》2012年第8期42-46,共5页Metallurgical Analysis

基　　金：四川省教育厅重点项目(10ZA060)

摘　　要：基于在盐酸介质中及90℃的条件下,痕量Ti(Ⅳ)对高碘酸钾氧化溴酚蓝褪色反应有显著的阻抑作用,且阻抑反应与非阻抑反应在波长599nm处的吸光度差值△A与Ti(Ⅳ)的质量浓度ρ在0.6～2.0μg/mL范围内呈良好的线性关系,建立了阻抑动力学光度法测定痕量钛(Ⅳ)新分析方法。方法的检出限为7.87×10-10 g/mL。对0.04μg/mL Ti(Ⅳ)标准溶液测定12次,求得标准偏差为1.2%。测定了动力学参数,反应物Ti(Ⅳ)是一级反应,总反应为准一级反应,表观速率常数为5.85×10-4/s,表观活化能为45.42kJ/mol。该分析方法用于Ti含量不同的两种炼钢烧结矿样品中Ti(Ⅳ)的测定,测定值与参照值吻合较好,相对标准偏差分别为2.4%和2.0%(n=6),加标回收率在98%～101%范围。Trace titanium（Ⅳ） had significant inhibitory action on the fading reaction of bromophenol blue oxidized by potassium periodate in hydrochloric acid medium at 90℃.Moreover,the absorbance difference（△A） between inhibitory reaction and non-inhibitory reaction showed good linear relationship with the mass concentration（ρ） of titanium  in range of 0.6-2.0 μg/mL at 599 nm.On the basis of this phenomenon,a new determination method of trace titanium （Ⅳ） by inhibitory kinetic spectrophotometry was established.The detection limit of this method was 7.87×10^-10 g/mL.The standard solution of titanium（Ⅳ）（0.04 μg /mL） was determined for 12 times with standard deviation of 1.2%.The kinetic parameters were measured.The results showed that this catalytic reaction was first order reaction for titanium（Ⅳ）,and the total reaction was pseudo first order reaction.The apparent reaction rate constant was 5.85×10^-4/s,and the apparent activation energy was 45.42 kJ/mol.The proposed method was applied to the determination of titanium（Ⅳ） in two steelmaking sinter samples with different contents of titanium.The determination results were consistent with the reference values.The relative standard deviations（RSD,n=6） were 2.4% and 2.0%,respectively.The recoveries of standard addition were in the range of 98%-101%,which could meet the analytical requirements of trace elements.

关 键 词：阻抑动力学光度法 高碘酸钾 溴酚蓝 钛(Ⅳ) 烧结矿 

分 类 号：O657.32[理学—分析化学]