原文由 ghost555 发表:
USP 品种项下对指定杂质按TLC进行,结果如下:
any spot from the solution under test is not greater in size and intensity than the spot at the respective R F produced by the Standard solution, corresponding to not more than 0.1% of this substance impurity.
原文由 ghost555 发表:
USP 品种项下对指定杂质按TLC进行,结果如下:
any spot from the solution under test is not greater in size and intensity than the spot at the respective R F produced by the Standard solution, corresponding to not more than 0.1% of this substance impurity.
原文由 ghost555 发表:
这里是USP 某原料药品种项下,对已知杂质进行控制的TLC方法。这句话是最后的结果。this substance impurity 即为该已知杂质的名字。是通过杂质对照品比较进行的TLC方法。想要知道的是,是不是将杂质标准液图谱上产生的RF点(即杂质标准品出现的点)与测试液图谱上出现的任何斑点,进行比较?那么是不是意味着,任何单个杂质均小于0.1%?还是仅对应的RF的点互比?
原文由 ghost555 发表:
USP 品种项下对指定杂质按TLC进行,结果如下:
..
原文由 ghost555 发表:
原文如下:
Fluorouracil(杂质)— Dissolve 250 mg in 10 mL of a mixture of glacial acetic acid and water (4:1). Apply 20 µL of this solution to a thin-layer chromatographic plate (see Chromatography 621 ) coated with a 0.5-mm layer of chromatographic silica gel mixture. To the same plate apply 20 µL, in 10-µL increments, of a 0.025 mg per mL solution of USP Fluorouracil RS in a mixture of glacial acetic acid and water (4:1). Develop the chromatogram in a mixture of chloroform and glacial acetic acid (13:7) until the solvent front has moved not less than 14 cm from the origin. Remove the plate from the developing chamber, and allow the solvent to evaporate. Locate the spots on the plate by observing under short-wavelength UV radiation: any spot from the solution under test is not greater in size and intensity than the spot at the respective R F produced by the Standard solution, corresponding to not more than 0.1% of fluorouracil.
原文由 ghost555 发表:
谢谢你,我也是这样理解的。不需要比较供试液中的所有斑点。我同事他们在搞劳,说是任何斑点 ...呵呵
原文由 yaya91 发表:
首先提醒楼主注意:做这个实验的目的是为了检查有关物质的。
一般做法如下:点两个样:一个为对照溶液,一般配成样品溶液的1%浓度;一个是样品溶液。
样品溶液出现多个杂斑点的现象是正常的,比较颜色深浅。只要没有超过标准就可以。这是一个比较粗的办法。假如精细一点要上色谱才行,液相是常用的方法。
标准中并没有限制杂斑点个数,只要3个杂斑点都浅于对照斑点,仍判为符合规定。