Discussion

1. What’s the method used for the elimination of the plasma protein interferences in this

analysis? What other usual methods are there for the elimination of the plasma protein interferences? What are the respective characteristics of them?

2. What are the purposes to keep the ASA standard solution at 4℃? Why should the

frozen plasma samples be thawed in the ice-water bath?

3. What are the aims of adding 0.1ml of 0.5ml/L hydrochloric acid during the sample

preparation?

4. Why should the MBA be added as the internal standard in the test? 5. What are the aims and significances of the recovery test?

teaching device

50ml beaker; 10ml centrifuge tube electronic balance 100ml volumetric flask transferpettor centrifugal machine

thermostat-controlled water-bath

high performance chromatograph of liquid

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实验五 维生素E胶丸的含量测定

教学目的

1. 掌握气相色谱法测定的原理与方法； 2. 掌握维生素E含量的操作条件及要点。 本章讲授提纲及学时分配

【性状】 ―――――――――――――（30min）

本品为微黄色或黄色透明的黏稠液体；几乎无臭；遇光色渐变深。 本品在无水乙醇、丙酮、乙醚或石油醚中易溶，在水中不溶。 【含量测定】 ―――――――――――――（7.5hour）

取装量差异项下的内容物，混合均匀，精密称取适量（约相当于维生素E 20mg），置棕色具塞锥形瓶中，照维生素E项下的方法，精密加入内标溶液10ml，密塞，摇匀，取1～3μl注入气相色谱仪，并依法测定校正因子，计算，即得。

照气相色谱法(中国药典2000年版二部附录Ⅴ E)测定。

色谱条件与系统适用性试验 以硅酮(OV-17)为固定相，涂布浓度为2％；柱温为265℃。理论板数按维生素E峰计算应不低于500，维生素E峰与内标物质峰的分离度应大于2。

校正因子测定 取正三十二烷适量，制备内标溶液。另取维生素E对照品制备对照品溶液，精密加入内标溶液10ml，混匀，取1～3μl注入气相色谱仪，计算校正因子。 本课程学科的新进展 GC的应用。 教学参考书

Journal of Chromatography A 本章内容的重点 气相色谱仪的使用 本章内容的难点 气相色谱仪的使用 本章内容及讲授的改进意见 复习思考题

1、 气相色谱测定维生素E含量时为什么使用内标法？ 2、 试述气相色谱法的特点及分析适用范围。

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3、 维生素E含量测定的其它方法有哪些？各有什么特点？ 教具及教学设备要求

具塞锥形瓶，电子天平，10ml容量瓶，气相色谱仪

Experiment 5 The Assay of Vitamin E

I. Purpose

1. To study the principles and procedures of gas chromatography for the assay of volatile

drugs.

2. To experiment on the assay of Vitamin E.

2. Contents and teach time assignment

Description ----------------------------------(30min)

A clear pale yellow or yellow viscous， oily liquid； almost odourless； the colur deepens on exposure to light.

Freely soluble in dehydrated ethanol， acetone， ether or petroleum ether； insoluble in water. Assay -------------------------------------------------(7.5hour)

Mix well the contents obtained in the test for Weight variation. To a quantity， accurately weighed， of the mixed contents equivalent to 20 mg of vitamin E add 10 ml， accurately measured， of internal standard solution in an amber coloured flask stoppered， shake well. Carry out the Assay described under vitamin E， injecting 1~3?l of the solution into the column and determine the correction factor accordingly. Calculate the content of C31H52O3.

Carry out the method for gas chromatography (Appendix V E， method 3)， using a column packed with 2% silicone (OV-17) as the stationary phase and maintain the column temperature at 265℃. The number of theoretical plates of the column is not less than 500， calculated with reference to the peak of vitamin E， and the resolution factor between the peaks of vitamin E and internal standard is not less than 2.

Dissolve a quantity of dotriacontane in n-hexane to produce a solution of 1.0 mg per ml as the internal standard solution. To 20 mg of vitamin E CRS， accurately weighed， in an amber coloured flask with stopper， add 10 ml of internal standard solution， accurately measured， stopper the flask， shake well. Inject 1 ~ 3?l into the column and calculate the correction factor.

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References

Journal of Chromatography A

Focal point

The use of gas chromatograph.

Discussion

1. Why is the internal reference standard method employed for the assay of Vitamin E by

GC?

2. Give an explanation of the features and applications of GC method? 3. What other methods are there for the assay of Vitamin E?

teaching device

conical flask electronic balance 10ml volumetric flask gas chromatograph

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