【摘要】 建立了一种测定海洋生物中不同形态硒的催化动力学光度法。在 pH=3的Clark -Lubs缓冲介质中 ,硒 (IV)能催化溴酸钾氧化甲基紫的褪色反应 ,硒 (IV)含量在0.14～8μg/L范围内与褪色反应速率成正比 ,生物样品经HNO3-HClO4 消化后直接测定硒 (IV)和有机硒含量 ,再经盐酸还原后测定总硒含量 ,两者差减得硒 (VI)含量。结合MIBK萃取分离干扰组分 ,该方法具有良好的选择性和准确度 ,用于海洋生物材料中不同形态硒的测定 ,操作简便快速 ,结果令人满意。对几种海藻和双壳贝类样品中硒的形态分析结果表明 ,在海洋生物中 ,硒主要以有机硒和硒 (IV)的形式存在于难溶性的大分子蛋白质中 ,硒 (VI)的含量普遍较低 ,且存在显著的种间差异。更多还原

【Abstract】 Trace selenium(IV) can catalyze the discolouring oxidization of methyl purple by potassium bromate in Clark-Lubs buffer solution with a pH value of 3.0. Based on this selective reaction of Se(IV), a new catalytic spectrophotometric method for the speciation analysis of selenium in marine organisms was developed. Digested with HNO3-HClO4 and reduced with HCl, organic Se was oxidized to Se(IV) and Se(VI) was reduced to Se(IV), the contents of total Se, Se(VI), Se(IV) and organic Se then could determined by catalytic spectrophotometry and differential method respectively. The method covers a linear detection range of Se of 0.14～8 μg/L and its absolute detection limit for Se in bio-material is 3.5 ng. Speciation analysis of selenium in several seagrass and bivalves was conducted with satisfactory results. Demonstrations that organic Se and Se(IV), the major species of selenium, mainly exist insoluble macro molecular proteins. The content of Se(VI) is commonly low and differs significantly between biologic species.更多还原