REVIEW ON INFRARED SPECTROSCOPY SPECTROSCOPY
SUBMITTED BY GUIDED BY
INDRAJIT GUCHHAIT MS. SURITA GHOSH
B.PHARM M.PHARM
4TH YEAR ASSISTANT PROFESSOR
UNIVERSITY REGN.NO.-014525 OF 2019-20 DEPARTMENT OF PHARMACEUTICS
UNIVERSITY ROLL NO : 18901919109
DR.B.C.ROY COLLEGE OF PHARMACY & ALLIED HEALTH SCIENCES,DURGAPUR -713206
AFFILIATED TO: MAULANA ABUL KALAM AZAD UNIVERSITY OF TECHNOLOGY , WEST BENGAL
CONTENT
Introduction
Types
Criteria for a compound to absorb IR Radiation
Fundamentals of IR Spectroscopy
Advantages
Types of Vibrations
Instrumentation
Application
Conclusion
Reference
INTRODUCTION
Spectroscopy-
Spectroscopy is a broad branch of research that examines and analyses the
electromagnetic spectra produced by the interaction of electromagnetic radiation with
matter as a function of wavelength or frequency. Radiative energy includes matter
waves and acoustic waves, and gravitational waves have recently been linked to a
spectral signature in the context of the Laser Interferometer Gravitational-Wave
Observatory (LIGO)
This energy may be ground state to excited state or excited state to ground state.
Types-
1.Atomic Spectroscopy-
Eg.-Atomic absorption spectroscopy ,Flame photometry.
2.Molcular spectroscopy-
Eg.- Uv spectroscopy, Colorimetry, Infra red spectroscopy.
INFRARED SPECTROSCOPY
Definition-
• Infrared spectroscopy is a useful tool for identifying the structure of both inorganic and
organic molecules.
• IR radiation wavelength of 0.7-400m.
• In every molecule, it is known that atoms or groups of atoms or groups of atoms are
connected by bonds. These bonds are analogous to springs and not ringed in nature. Because
of continuous motion of the molecule they maintain some vibrations with some frequency
characteristic to every portion of the molecule .This is called the natural frequency of
vibration . When energy in the form of infrared radiation is applied,
• Applied infrared frequency = Natural frequency of vibration,
• Absorption of IR radiation takes place and a peak is observed.
CRITERIA FOR A COMPOUND
TO ABSORB IR RADIATION
1.Change in Dipole Moment.
2. When the inherent frequency of vibrations of some parts of a molecule is the same as
the frequency of incident radiation, the molecule absorbs radiation.
• 3.A molecule can only absorb IR radiations when its absorption causes a change in its
electric dipole.
• 4. A polar bond is usually IR active whereas non polar bonds in a symmetrical molecule
will absorb weakly or not at all.
• 5. A molecule is said to have an electric dipole when there is a slight positive & a slight
negative charge on its component of atoms.
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FUNDAMENTALS OF IR SPECTROSCOPY
• The measurement of the interaction of infrared light with matter by absorption, emission, or
reflection is known as infrared spectroscopy (IR spectroscopy or vibrational spectroscopy).
• It's utilised to investigate and identify chemical compounds or functional groups that exist in solid,
liquid, or gaseous forms. It may be used to identify and validate known and unknown samples, as
well as to describe novel materials. Infrared spectroscopy is a method or technique that uses an
equipment called an infrared spectrometer (or spectrophotometer) to obtain an infrared spectrum. A
graph showing infrared light absorbance (or transmittance) on the vertical axis vs. frequency,
wavenumber, or wavelength on the horizontal axis can be used to view an IR spectrum.
• The near-infrared, mid-infrared, and far-infrared parts of the electromagnetic spectrum are commonly
split into three categories based on their relationship to the visible spectrum.
• Near-IR light with a wavelength of 14,000–4,000 cm1 (0.7–2.5 m) can excite overtone or
combination modes of molecular vibrations.
• The mid-infrared, which ranges from 4,000 to 400 cm1 (2.5–25 m), is commonly employed to
investigate basic vibrations and their accompanying rotational–vibrational structure. The far-infrared
has a low energy range of 400–10 cm1 (25–1,000 m) and can be used for rotational spectroscopy and
low frequency vibrations.
ADVANTAGES
All kinds of materials
can be analyzed. Provides lot of informations
Less expensive.
Very small amount of
Sample is required.
Fast and Easy.
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TYPES OF VIBRATIONS
1.Stretching Vibrations
(a). Symetrical stretching
(b).Assymetrical Stretching
2.Bending Vibrations
(a).In plane bending
(i) Scissoring
(ii) Rocking
(b)Out-of plane bending
(i)Wagging
(ii) Twisting
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INSTRUMENTATION
Components of spectrophotometer-
• 1.Radiation source
• 2.Sample cells and sampling of substances
• 3.Monochromators
• 4.Detectors
• 5.Recorder
https://microbenotes.com/infrared-ir-spectroscopy/h
APPLICATION
Cis-trans isomer is
Drugs in Formulations determined
Determination
APPLICATION
Gaseous, liquid,
Exploration of space Compound
or solid sample
identification
analysis
CONCLUSION
. Infrared spectroscopy (IR) identifies the components of a sample (liquid, solid or gas)
Infrared (IR) spectrometers determine how IR radiation interacts with substances. The
FTIR spectrometer determines the frequencies at which the samples absorb radiation, as
well as the intensity of those absorptions. A spectrum depicts the intensity and frequency of
sample absorption in a two-dimensional graphic. The quantity of light absorbed by a sample
is measured in absorbance, whereas the amount of light that flows through it is measured in
percent transmittance. This approach can provide vital information on what makes up an
unknown sample and how much of each component is present in that sample. It has a wide
range of uses, including research and development of new products.
REFERENCES
1. R. Escobedo, R. Miranda, and J. Martínez, “Separation of organic and inorganic compounds
for special applications,” International Journal of Molecular Sciences, vol. 17, pp. 1–26,
2016.
2. K. Arora and A. Parma, “Simulation of IR spectra of some organic compounds-A
review,” IOSR Journal of Applied Chemistry, vol. 6, no. 1, pp. 10–24, 2013
3. R. M. Silverstein, G. C. Bassler, and T. C. Morrill, Spectrometric Identification of Organic
Compounds, 4th ed. (New York: Wiley, 1981), 166.
4. Dr. S. Ravi Sankar, ’Text book of Pharmaceutical Analysis’:4th edition. Trirunalveli; pp 1-
35,5.1-5.7,2010.
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