APPLICATION OF UV VISIBLE SPECTROSCOPY

1. DEPARTMENT OF
PHARMACY,
GGV BILASPUR (C.G.)
Name:- Lomash , M-pharm 1st Sem.
Assignment topic :- application of uv visible spectroscopy

2. • Defination:
It is a branch of science that deals with the study of interaction of electromagnetic
radiation with mater.
Or
It is a branch of science that deals with the study of interaction of mater with light.
• Application of UV visible Spectroscopy :-
1. Detection of impurities
2. Structure elucidation of organic compounds
3. Quantitative analysis
4. Qualitative analysis
5. Chemical kinetics
6. Detection of functional groups
7. Quantitative analysis of pharmaceutical substances
8. Examination of poly nuclear hydrocarbon

3. 9) Molecular weight determination
10) As HPLC detector
1. Detection of impurities
Uv absorption spectroscopy is one of the best methods for determination
of impurities in organic molecules. Additional peaks can be observed due
to
impurities in the sample and it can be compared with that of standard raw
material. By also measuring the absorbance at wavelength, the impurities
can be detected.

4. 2) Quantitative analysis
Uv adsorption spectroscopy can be used for quantitative deterioration of
Compound that absorb uv radiation this determination is based on beer’s
law which is as follows-
A = log Io / It= log I/T = - log T = abc = Ebc
Whare,
E= is extinction co – efficient
C = is concentration
b = is the length of the cell that is used in uv
spectophotometer

5. 3) Qualitative analysis
Uv absorption spectroscopy can characterize those type of compounds
which absorbs uv radiation identification is done by comparing the
absorption spectrom with the spectra of know compound

6. 4) Structure elucidation of organic compounds.
• Uv spectroscopy is useful in the structure elucidation of organic
molecules, the presence and absence of unsaturation, the presence
of hetero atoms.
• From the location of peaks and combination of peaks, it can be
concluded that whether the compound is saturated or unsaturated
hetero atoms are present or not etc.

7. 5) Chemical kinetics
Chemical kinetics of reaction can also be studied using uv
spectroscopy. The uv radiation is passed through the reaction
cell and the absorbance changes can be or observed.
6) Detection of functional groups
This technique is used to detect the presence or absence of
functional groups in the compound.
Absence of a band at particular wavelength regarded as an
evidence for absence of particular group.

8. 7) Quantitative analysis of pharmaceutical substances
many drugs are either is the form of raw material or in the form of
formulation they can be assayed by making a suitable solution of the
drug in a solvent and measuring the absorbance at specific wave-
length.
Diazepam tablet can be analyzed by 0.5% sulphuric acid in
methanol at the wavelength 284.

9. 8) Examination of poly nuclear hydrocarbons
• Benzene and poly nuclear hydrocarbons have characteristics spectra
in ultraviolet and visible region. Thus identification of poly nuclear
hydrocarbons can be made by comparison with the spectra of known
poly nuclear compounds.
• Poly nuclear hydrocarbons are the hydrocarbon molecules with two
more closed rings,
Exa. Naphthaline , C10 H8, with two benzene ring side by side . Or
Diphenyl (C6 H5)2 with two bond – conected benzene ring also
known as polycyclic hydrocarbon.

10. 9) Molecular weight determination
• Molecular weight of compounds can be measured specto- photometrically
by preparing the suitable derivatives of these compounds.
For exam.
If we want to determine the molecular weight of amine then it is
converted in to amine pirate then known conc. Of amine pirate is dissolved
in a litre of solution and it optical density is measured at lambda max
380nm.
10) As HPLC detector
A uv/ vis spectophotometer may be used as a detector for HPLC.