INSTRUMENTAL METHODS OF ANALYSIS Question Papers (2008, Aug/sep,supple)

SET : 1

1. (a) Define the terms qualitative and quantitative analysis. (b) Differentiate between micro and semi-micro analytical methods. (c) What are advantages and limitations of chemical methods.

2. Compare and contrast the techniques phase contrast microscopy and differential interference contrast microscopy (DIC).

3. Explain the following terms:

• Gravitational force
• Centrifugal force
• Sedimentation coefficient.

4. You have two samples of DNA derived from different organisms, A and B. DNA from A shows an increase in optical density beginning at 70 C and plateau at 80 C. DNA from B shows a corresponding increase in O.D beginning at 65 C and plateau out at 76 C. what is your conclusion. Justify your answer.

5. (a) Define fluorescence. Derive an expression relating intensity of fluorescence and concentration.
(b) Write a brief note on:

• Triplet state
• Doublet state
• Singlet state

6. (a) Discuss the basic principle of infrared spectroscopy? (b) Briefly describe the scanning of infrared spectrum of an organic compoung.

7. Explain the following:

• Free inductive decay
• Hetero nuclear decoupling
• Off resonance coupling
• Chemical shift

8. Give an account on electronic structure and hyperfine splitting in ESR spectroscopy?

SET: 2

1. Give a brief account on methods for reporting analytical data?

2. Compare and contrast the optical magnification obtained by the bright and dark field microscopy along with their specific applications.

3. (a) Give the basic principle involved in analytical centrifugation. (b) What are the important applications of this technique in biochemistry?

4. You have two samples of DNA derived from different organisms, A and B. DNA from A shows an increase in optical density beginning at 70 C and plateau at 80 C. DNA from B shows a corresponding increase in O.D beginning at 65 C and plateau out at 76 C. what is your conclusion. Justify your answer.

5. (a) Define optical activity? What is the principle involved in circular dichroism spectroscopy? (b) Differentiate polarimetry and circular dichroism.

6. Discuss the principle, importance and applications of mass spectrometry?

7. (a) Give the principle underlying in NMR spectrometry? (b) Describe the component of a NMR spectrometer with a neat labeled diagram.

8. (a) What is the principle of ESR. Discuss some important applications of ESR. (b) What are the limitations of ESR.

SET :3

1. Give an account of the instruments involved in electrochemical methods of analysis along with their principle of working.

2. (a) Give the basic principle involved in the viewing an object in dark field. (b) Draw a neat labeled diagram of optical pathway of dark field microscope. (c) Give its specific use.

3. (a) Give the basic principle involved in analytical centrifugation. (b) What are the important applications of this technique in biochemistry?

4. What are the different regions of the electromagnetic spectrum and where are they used for?

5. Define the following terms:
Chiral compounds
Cotton effect
Circular birefringence.
6. How will you distinguish between intermolecular and intramolecular hydrogen bonding by IR spectroscopy?

7. (a) Explain the principle involved in CMR spectra? (b) Why it is not possible to determine relative ratio of carbon atoms in a compound by integration of peak areas in 13C NMR as in PMR?

8. Why ESR spectroscopy is widely used in the study of chemical, photochemical and electrochemical reactions? Justify your answer.

SET: 4

1. Write an account on analytical methods based on the physical property measurement?

2. Narrate the principle of operation of a fluorescence microscope. Give its applications in biology?

3. Calculate the molecular mass of the protein where the sedimentation coefficient of the protein is 7.75 * 10 power -12 s. In subsequent analysis the protein was found to have an average diffusion coefficient of 4.0 * 10 power -11 Sq.mt per sec. and the partial specific volume of 0.734 * 10 power -3 cub.mt per kg.

• Convert the molecular mass to relative molecular mass.
• express the molecular mass in Daltons.

4. Define the terms:
(a) (i) Radiant power (P)
(ii) Path length of radiation
(iii) absorptivity
(iv) molar absorptivity
(b) Describe and derive the Beer's law.
(c) What are its limitations and deviations.

5. (a) What is atomic absorption. What are its advantages and disadvantages. (b) Give some of its limitations.

6. (a) What are the different regions of infrared radiation? (b) Explain various types of streching and bending vibrations with suitable examples.

7. (a) why does a signal for a particular set of protons in split into a multiplet. (b) Explain with suitable examples the term spin-spin coupling.

8. (a) Which of the following two formula is correct for the complex obtained between copper ion and 8 quinolinethanol (C9H7N5)
(i) Cu(I) (C9H7N5) (C9H6N5)
(ii) Cu (II) (C9H6N5)2.
Show that the ESR approach is appropriate for this determination.
(b) Which is one of the best known free radicals used in calibrating ESR spectra?