| There are four parts in this paper, at first, all kinds of related reference literatures are reviewed, and the importance of these studies is illustrated.. The chemical principles of dendribium moniliform are researched in the second part, and five principles are separated, one of them is a chemical compound named as Stigmasterol, another one is Cholesta-22,24-dien-5-ol,4,4-dimethyl-, which can not be reported in dendribium, and a kind of alkaloid is found. In the third part of this paper, Extraction of active principles in natural medicine such as salvia mitiorriza, lignsticum wallichii, rhizoma gastrodiae and forsythia suspensa is studied. Three methods which include high performance chromatograph, ultraviolet-visible spectrophototry and the comparison method of efficiency of extraction are used to evaluate four ways of extraction, it shows that ultrasonic assistied solvent extraction method is most efficient and quickest. And the effect of duration of the ultrasonic on extraction is researched. The spectrophotometric determination of iodine in sargassum fusiforme is studied in the last part of this paper. The sample is decomposed by oxygen bomb method using sodium hydroxide and hydrazine sulfate solution as absorbent, bromine as oxidizer. Iodic acid is reduced to free iodine by using potassium iodide as reductant. The result of determination is (O.398監.023)%. This method is proved to be simple, accurate and reproducible. It has been satisfactorily used for the determination of iodine in sargassum fusiforme. |
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