Chromatography.

Chromatography has opened up new fields of medical research especially in pharmacy. Chromatography has greatly extended our knowledge of biochemistry and drug metabolism.

Chromatography is a process of separating the components of a mixture by producing different rates of movement for each component in a countercurrent system¹. Different rates are thus produced for each solute, and a physical separation is achieved.

Chromatographic methods have developed so rapidly that they are now regarded the most powerful tools available for separation and purification of natural products.

In 1906 the Russian botanist Tswett published an article on his technique for separating the pigments of green leaves by absorption on columns of precipitated chalk. Instead of percolating a solution of the mixed pigments through the column, Tswett applied a small quantity of the pigment onto the top of the packing and then let a light petroleum solvent run through² it. This resulted in a gradual separation of coloured bands that moved down the column at different rates, and each coloured band represented a different pigment. Tswett referred to this technique as “the chromatographic method”. That is why he is now generally regarded as the “father” of chromatography.

However, little attention was paid to his method for some 25 years, until interest in chromatography was revived in 1931 by the work of Kühn, Lederer and Wintersteiner, who separated the plant carotenoid pigments by means of³ this technique.

A major advance in chromatography was connected with the development of synthetic ion exchange resins⁴ . The technique has been applied to a large number of organic compounds and has proved especially useful for separating acidic and basic substances from mixtures.

Notes

1. countercurrent system – протиточна система

2. let smith run through – пропускати що-небудь через

3. by means of – за допомогою, шляхом

4. synthetic ion exchange resins – синтетичні іонообмінні смоли.

Exercises

Ex.1. In the text, find the nouns of the same root with the verbs below; translate

To know, to mix, to move, to solve, to separate, to purify, to produce, to absorb, to work, to develop.

Ex.2. Find the antonyms of the following words in the text:

Old; to close; ignorance; to connect; slowly; contamination; artificial; large; bottom; the same; much; inorganic.

Ex.3. Find the synonyms of the following words in the text:

Areas; to widen; medicine (ліки); various; quickly; to be considered (вважатись); with the aid of; progress; has been used.

Ex.4. Ask general questions, give short answers:

Example: He has travelled all over Europe. –

Has he travelled over Europe? - Yes, he has\ No, he hasn’t.

1. The students have written a test-paper today.

2. You have prepared everything for the experiment.

3. The progress of chemistry has taken place in all directions.

4. The temperature above 60°C to 80°C has produced a marked change in the structure of egg albumin.

5. Chromatography has extended our knowledge of biochemistry.

6. The technique has proved very important for separating substances from mixtures.

7. Chromatographic methods have developed rapidly for the past 50 years.

8. We have understood the use of the Present Perfect Tense.

Ex.5. Find the sentences in which Perfect Active is used. Translate:

1. Academician R. Chagovets has proved that the so-called coenzyme vitamins belong to ancient elementary organic compounds.

2. Purification of this substance usually takes place in 2 stages.

3. He will have found out the molecular weights of these proteins by 10 o’clock tomorrow morning.

4. When the temperature had risen above 80°C, it produced a marked change in the structure of the substance.

5. Chemists use chromatography for separating acidic and basic substances from mixtures.

6. The most interesting changes were taking place when we raised the temperature above 60°C.

7. I’m afraid the lecture will already have started by the time we get to the university.

Ex.6. Match the lines in A with the lines in B and translate:

A

B

The scientific and technical revolution Many interesting investigations Ukrainian scientists The scientific research centre in Kiev The achievements of Ukrainian medical chemistry Ukrainian and foreign scientists Semi-synthetic and synthetic antibiotics, hormones and new groups of cardio-vascular drugs Chemistry Recently surgeons, dentists and other medical specialists The growing development of new drugs and medicinal substances

a) have widely used plastics and synthetic fibres and materials in their practice. b) have considerably reduced the number of diseases. c) has become possible due to the achievements of Ukrainian science, increase in the number of research institutes and pharmaceutical plants and their up-to-date re-equipment. d) has changed the technology, organization and economy of production. e) have signed several agreements on joint work in various fields. f) have been done on the synthesis of compounds of inorganic substances for medical purposes. g) have developed effective medicines, blood substitutes, artificial organs. h) has developed new drugs effective in the treatment of nervous and eye diseases. i) has not only given us new drugs but also new and effective methods for diagnosing diseases and their treatment. j) have drawn great interest from abroad.

Ex.7. Open the brackets, put the verbs into Present, Past or Future Perfect:

1. The progress of chemistry (to enable) Ukrainian scientists to produce hundreds of new chemical products.

2. The reverse process took place when all the molecules (to link –з’єднувати) together in chains.

3. The repeated experiment (to show) that the composition of mixture can be calculated within 5%.

4. After the alcoholic solution is poured into water and evaporated long enough, the precipitate (to coagulate) completely.

5. We (to describe) an intermediate product, isolated in the reaction.

6. After the reaction (to take place) the product gave an intense coloration.

7. Yesterday I met Prof. Tomenko, who (to be) my University lecturer 5 years ago.

8. Digitalis (to be) the subject of long investigation.

9. They (to finish) their experiments by the end of this year.

10. The progressive decrease in the molecular complex (to stop) by the end of the reaction.

Ex.8. Put in the necessary words using the text:

1. Chromatography has opened up new fields of … .

2. Chromatography has … extended our knowledge of biochemistry and drug metabolism.

3. Chromatography is a process of … of a mixture in a countercurrent system.

4. … are now regarded as the most powerful tools available for separation and purification of natural products.

5. … percolating a solution of the mixed pigments through the column, Tswett applied … onto the top of the packing.

6. Tswett is now generally … as the “father” of chromatography.

7. … was connected with the development of synthetic ion exchange resins.

8. The technique has proved …for separating acidic and basic substances from mixtures.

Слова: instead of, especially useful, chromatographic methods, regarded, medical research, a small quantity, greatly, a major advance in chromatography, separating the components.

Ex.9. Answer the questions on the text:

1. What role has chromatography played in medical research?

2. What kind of method is chromatography?

3. What are chromatographic methods used for?

4. Who was the first to describe the method?

5. When did the Russian botanist Tswett publish the article on his technique?

6. In what way did Tswett separate each pigment from a mixture?

7. What happened in 1931?

8. When did a major advance in chromatography begin?

9. What are chromatographic methods regarded at present?

10. What has the technique proved especially useful for?