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
6.
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
8.
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
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
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
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