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【求助】PVP K-30的检测方法。
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如何检测PVP,k-30的含量呢，要求简单点，仪器检测在小公司很难执行。 最好有滴定分析。谢谢各位达人。 |
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ASSAY for Povidone K30 from BP Place 100.0 mg of the substance to be examined (m mg) in a combustion flask, add 5 g of a mixture of 1 g of copper sulphate R, 1 g of titanium dioxide R and 33 g of dipotassium sulphate R, and 3 glass beads. Wash any adhering particles from the neck into the flask with a small quantity of water R. Add 7 ml of sulphuric acid R, allowing it to run down the sides of the flask, and mix the contents by rotation. Close the mouth of the flask loosely, for example by means of a glass bulb with a short stem, to avoid excessive loss of sulphuric acid. Heat gradually at first, then increase the temperature until there is vigorous boiling with condensation of sulphuric acid in the neck of the flask; precautions are to be taken to prevent the upper part of the flask from becoming overheated. Continue the heating for 45 min. Cool, dissolve the solid material by cautiously adding to the mixture 70 ml of water R, cool again and place in a steam-distillation apparatus. Add 30 ml of strong sodium hydroxide solution R through the funnel, rinse cautiously the funnel with 10 ml of water R and distil immediately by passing steam through the mixture. Collect about 80-100 ml of distillate in a mixture of 30 ml of a 40 g/l solution of boric acid R and 3 drops of bromocresol green-methyl red solution R and enough water R to cover the tip of the condenser. Towards the end of the distillation lower the receiver so that the tip of the condenser is above the surface of the acid solution and rinse the end part of the condenser with a small quantity of water R. Titrate the distillate with 0.025 M sulphuric acid until the colour of the solution changes from green through pale greyish-blue to pale greyish-red-purple (n1 ml of 0.025 M sulphuric acid). Repeat the test using about 100.0 mg of glucose R in place of the substance to be examined (n2 ml of 0.025 M sulphuric acid). 是凯式定氮法，主要是玻璃仪器以及滴定，应该比较简单，另外也可参考ChP2005 921页 《聚维酮 K30》 |
2楼2008-12-25 12:19:21
3楼2008-12-25 16:44:42
