No. of Printed Pages: 3 1MCH-0021
P.G. DIPLOMA IN ANALYTICAL CHEMISTRY
(PGDAC)
Term-End Examination
December, 2016

00225
MCH-002 SEPARATION METHODS
Time hours Maximum Marks: 75
Note: Attempt any five questions. Marks are indicated against each question.

1. The distribution ratio of solute A in water-organic phase is 10. Calculate the percentage of A extracted from 50 ml of water by 100 ml of organic phase. 5

Give a brief account of the separation methods based on molecular geometry. Support your answer citing an example in each case. 5

Explain what happens when extraction is carried out using an extractant whose density and interfacial tension is quite close to the aqueous phase. 5

2. Explain the terms retention time and retention factor. In what range should retention factors lie for ideal separations? 5

Write van Deemter equation and explain all the terms briefly. 5

What are the various stationary phases used in solid-liquid column chromatography? 5

3. Explain the basic principle of HPLC. How is HPLC useful in speciation studies Illustrate your answer with a suitable example. 7

Why are alkyl phosphorus acids preferred over a carboxylic acid for the extraction of a metal ion Explain with the help of an example. 5

Write a brief note on autoradiography. 3

4. Discuss the importance of loading buffer in DNA gel electrophoresis. Of the linear and supercoiled DNA, which one moves faster when subjected to agarose slab electrophoresis? Give reason. 5+5

Draw a labelled graph ,depicting the relationship between number of plates and separation factor. 5

5. Write short notes on the following: 3x5=15

Rf value

Plate concept applied to TLC

Thermal conductivity detector

6. Explain the principle of Ion-Exchange chromatography. Illustrate the use of this technique in separating a mixture of amino acids. 10

List the methods for development of a chromatographic column in case of liquid-liquid chromatography. 5

7. Explain gas chromatography and HPLC methods. Compare the two methods and describe the advantages of HPLC. 10

Draw the structure of silica gel depicting various types of hydroxyl groups. Explain their role in the separation processes. 5

8. Briefly describe a typical gel structure. What is a macro-micro reticular gel Mention its special advantages for chromatographic work. 7

What are the different forms of electrophoresis Explain each of these with suitable illustrations. 8