长光路光度法测定中药材中痕量硒

Determination of Trace Selenium in Crude Drugs by Spectrophotometry with a Long-light-path

本文研究了用长光路光度法测定痕量硒。在酸性溶液中，Ｓｅ（Ⅳ）催化ＫＣｌＯ３氧化苯肼成偶氮离子，继而与变色酸生成红色偶氮化合物。硒含量在１．０×１０－９～２．０×１０－７ｇ／ｍＬ范围内遵守比尔定律。巯基棉分离后，测定中药材中总硒，获得满意结果。

A spectrophotometry with a long-light-path for determination of trace Se(Ⅳ) was studied. In acidic solution, Se(Ⅳ) can catalyze the oxidation of phenylhydrazie. by KClO3, and the formed diazoene-diazonium ion can couple with chromotropic acid to give the red azo compound.Therefore, a method was developed for the determination of Se(Ⅳ ) . Beer's law was obeyed in the concentration range of 1. 0 × 10-9～2. 0 × 10-7g/mL Se (Ⅳ ) and the detection limit was 1. 1 × 10-11g/mL Se (Ⅳ). Interfering ions were eliminated by seperation with thiohydroxy cotton, .Se in some crude drugs was determined with good results.