1. Optical Rotatory Dispersion &
Circular Dichorism
 Presented by:-
 Sukhjeet kaur
 M.Sc. (H)
biotech(2)
 130181106

2. CONTENT
 ORD
 PRINCIPLE
 FUNDAMENTAL OF ORD
 CD
 COTTON EFFECT
 ORD CURVES
 APPLICATION
 DIFFERENCE B/W ORD & CD
 CONCLUSION

3. ORD
 ORD is technique related to the optical
activity
 Rate of change of specific rotation
with change in wave length
 Optical rotation caused by compound
changed with wavelength of light was
first denoted by Biot in 1817

4. FUNDAMENTAL OF ORD
 Plane polarized light
 Optical activity
 Specific rotation
 Circular birefringence
 Optical rotation
 Elliphicity

5. Plane polarized light
 Light from ordinary lamp consists of
waves vibrating in many different
planes
 It is passed through Polaroid lens it is
found to be vibrate in one plane is said
to be plane polarized light

7. OPTICAL ACTIVITY
 The compounds which are having the
ability to rotate the plane of polarized
light are called optical active
compound
 This property of compounds is called
optical activity
 Measured by Polarimeter
 Dextrorotatory
 Levorotatory

9. SPECIFIC ROTATION
 The specific rotation ([α]) is
an intensive property of a chemical
compound, defined as the change in
orientation of the plane of linearly
polarized light as this light passes
through a sample with a path length of
1 decimeter and a sample
concentration of 1 gram per 1 millilitre
 It is denoted by [α]

10. CIRCULAR
BIREFRINGENCE
 Birefringence is the optical property
of a material having a refractive
index that depends on
the polarization and propagation
direction of light
 α= (nL-nR)π/ α

11. CIRCULAR DICHORISM
Some material posses special properties of
absorption of the light circularly light to
different extent than the right circulary
polarized light
Chiral or asymmetric compounds produce
CD spectrum

12. COTTON EFFECT
This phenomenon
was discovered in
1895 by the French
physicist Aimé
Cotton
Combination of
circular dichorism
& circular
birefringence

13. ORD CURVES
 Plain curves
 Anomalous curves
 single cotton effect curves
 multiple cotton effect curve

14. PLAIN CURVES
 Normal smooth curves
 Do not cross the zero rotation line
 e.g.:- alcohols hydrocarbons

15. ANOMALOUS CURVES
 Shows no. of extreme peaks &
troughs

16. SCEC & MCEC
 Two or more peaks
& trough
 e.g. ketosteroids
 camphor

17. APPLICATION
 CD/ORD of protein
 Qualitative analysis of molecules
 Enzyme co-factor evaluation
 CD/ORD of proteins
 CD as finger printing
 CD/ORD of nucleic acids
 CD of B-DNA is different as compared to A-
DNA
 Evidence for base stacking

18. CD/ORD of proteins
 e.g:- L-lysine
 Positive CD at 217nm
 Negative CD at 197nm
 Random coil :- ph 5.2
 Alpha helical :- ph 11.0

19. QUALITATIVE ANALYSIS
 Measuring by the specific rotation
 α =100 α /lc

 m =M α /100

20. Enzyme co-factor evaluation
 Teng et.al carried out the spectrum of
enzyme p-hydroxybenzoate

21. CD as finger printing
 It acts as finger printing technique for
trace amount of carbohydrate meterial
 E.g. dermatan sulphate
 heparitin sulphate
 E.g :- pectin in the presence of citric
acid& sucrose

22. CD of B-DNA & A-DNA

23. BASE STACKING
 ORD spectrum of Polycytidylic acid
shows at 292nm is 35,160deg/M/cm
 HELICITY DETERMINED BY
 Formaldehyde
 Ethylene glycol

24. DIFFERENCE B/W ORD &
CD
ORD CD
PLANE POLARIZED LIGHT
DISPERSIVE PHENOMENA
PLANE POLARIZED IS USED &
IS NOT CONVERTED TO
ELLIPTICAL LUGHT
GRAPHS ARE OBTAINED BY
SPECIFIC ROTATION V/S
WAVELENGTH
CIRCULARLY POLARIZED
LUGHT
ABSORPTIVE PHENOMENA
CIRCULAR POLARIZED LIGHT IS
USED & IS CONVERTED TO
ELLIPICITY
GRAPHS ARE OBTAINED
MOLAR ELLIPICITY V/S WAVE
LENGTH

25. INSTRUMENTATION OF
ORD
 Light source
 Monochromator
 Polarizer
 Analyzer
 Sample tube
 photomultiplier

26. INSTRUMENTATION OF CD
 Light source
 Polarizer
 Sample tube
 Photomultiplier
 Recorder

27. CD SPECTROSCOPE

29. CD/ORD
 Simple and quick experiments
 No extensive preparation
 Relatively low concentrations/amounts
of sample
 Microsecond time resolution
 Any size of macromolecule
 Better resolution
 Better sensitivity
 Easier to assign

30. REFERENCE
 WWW. Science direct.com
 WWW.notes .com
 Principles & techniques by Avinash
Upadhyay
 WWW.scribd.com

31.  THANK YOU