乙醇-硫酸铵双水相萃取分光光度法测定粮食中钼含量  

Spectrophotometric Determination of Molybdenum in Grain with Extraction From Bi-aqueous Medium of Ethanol and Ammonium Sulfate

作　　者：刘奇[1] 刘改霞[1] 李全民[1] 

机构地区：[1]河南师范大学化学与环境科学学院,河南省环境污染控制重点实验室,新乡453007

出　　处：《理化检验（化学分册）》2010年第6期674-676,共3页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：河南省自然科学基金(2000150034);河南省高校环境科学与工程重点学科实验室项目资助

摘　　要：试验表明:在乙醇-硫酸铵双水相体系中,所形成的乙醇相对钼与水杨基荧光酮红色络合物具有增敏作用。在pH 3的乙酸-乙酸钠缓冲溶液条件下,钼与水杨基荧光酮形成1∶2的稳定红色络合物,在乙醇-硫酸铵双水相体系的乙醇相中,该络合物的最大吸收波长为516 nm,与单一水溶液中络合物相比,发生了2 nm波长的红移现象。在乙醇相中钼(Ⅵ)-SAF络合物的表观摩尔吸光率为1.12×105L.mol-1.cm-1,钼(Ⅵ)质量浓度在20 mg.L-1以内与其对应的吸光度呈线性关系。方法的检出限(3S/N)为0.06 mg.L-1。该方法应用于粮食作物中微量钼的测定,测得方法的回收率为97.4%～100.1%。It was found that the sensitivity of the red colored complex of Mo（Ⅵ）-salicylfluorone（SAF） with its mole ratio of 1 to 2,formed in pH 3.0 acetate buffer medium containing ethanol and ammonium sulfate（called bi-aqueous medium） was enhanced as compared with the same chromogenic reaction carried out in unitary aqueous medium without the addition of ethanol.Upon extraction by shaking the reaction mixture for 2 min,the Mo（Ⅵ）-SAF complex was transferred into the upper ethanol phase,having its absorption maximum at 516 nm（spectral change of bathochromic shift of 2 nm as compared with the Mo（Ⅵ）-SAF complex in unitary aqueous medium）.Value of apparent molar absorptivity found was 1.12×105L·mol-1·cm-1 in ethanol phase.Linear relationship between values of absorbance and mass concentration of Mo（Ⅵ） was kept in the range within 20 mg·L-1,with detection limit（3S/N） of the method of 0.06 mg·L-1.The proposed method was applied to the determination of Mo（Ⅵ） in grain samples,giving values of recovery in the range of 97.4%-100.1%.

关 键 词：分光光度法 双水相 萃取 钼(Ⅵ) 

分 类 号：O657.3[理学—分析化学]