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维生素 A 含量测定

维生素 A 含量测定. UV 法. 杂质:立体异构体、合成中间体、讲解氧化产物,具有不相关吸收,采用三点校正法。. 1. 校正原理: ( 1 )杂质的吸收在 310-340nm 波长范围内呈一条直线,且随波长的增大吸收度减小; ( 2 )物质对光的吸收具有加和性。. 2. 波长的选择: ( 1 )  1 VitA 的 max ( 325nm-328nm ) ( 2 )  2 、 3 分别在 1 的两侧各选一点. 第一法 等波长差法 测定对象 VitA 醋酸酯. 第二法 等吸收度法 ( 皂化法 )

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维生素 A 含量测定

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  1. 维生素A含量测定

  2. UV法 杂质:立体异构体、合成中间体、讲解氧化产物,具有不相关吸收,采用三点校正法。 1. 校正原理: (1)杂质的吸收在310-340nm波长范围内呈一条直线,且随波长的增大吸收度减小; (2)物质对光的吸收具有加和性。

  3. 2. 波长的选择: (1) 1 VitA的max(325nm-328nm) (2) 2、3分别在1的两侧各选一点

  4. 第一法 等波长差法 测定对象 VitA醋酸酯

  5. 第二法 等吸收度法(皂化法) 测定对象 VitA醇

  6. 三氯化锑比色法标准曲线法 λmax 618nm~620nm

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