Gritta ftir

FACILITATORS:Dr. B.M. GurupadayyaProfessorDr. R.S. ChandanAsst. ProfessorDept. of pharmaceutical chemistry

JSS Universitycollege of pharmacyMysore

FOURIER TRANSFORM INFRARED

PRESENTED BY

Gritta Sebastian

Ist M.Pharm

Dept. of Pharmaceutics

JSS University

College of pharmacy

Mysore

TYPES OF IR INSTRUMENTS

IR instruments can be classified as:

1.Dispersive instruments

• Single beam IR spectrophotometer

• Double beam IR spectrophotometer

2.Non-Dispersive instruments

• Fourier transform infrared (FTIR) spectrometer

Fourier Transform Infrared (FT-IR) Spectroscopy is a modern tool to study the characteristics of molecules, either in solid, liquid or gas phase.

An FTIR spectrometer simultaneously collects spectral data in a wide spectral range.

The term Fourier transform infrared spectroscopy originates from the fact that a Fourier transform (a mathematical process) is required to convert the raw data into the actual spectrum.

FTIR spectroscopy is preferred over dispersive methods of infrared spectral analysis for several reasons:

It is a non-destructive technique

It provides a precise measurement method which requires no external calibration

It can increase speed, collecting a scan every second

It has greater optical throughput

It is mechanically simple with only one moving part

FTIR V

FTIR’s COMPONENTS

IR radiation source

Beam splitter

Fixed mirror

Moving mirror

Helium-Neon laser

Collimating mirrors

Sample holder

Detector

FTIR seminar

Interferometer

He-Ne gas laser

Fixed mirror

Movable mirror

Sample chamber

Light source

(ceramic)

Detector

(DLATGS)

Beam splitter

FT Optical System Diagram

The figure above shows what is referred to as the Michelson interferometer

Radiations from the source falls on the interferometer

It comprises of beam splitter, moving mirror, fixed mirror

The beam splitter splits the light into two half beams of equal intensities

One half of the beam is passed to the fixed mirror, Other half is directed towards the mirror

Light enters the spectrometer and is split by the beam splitter.

Speed of the moving mirror is controlled by

using a helium-neon laser beam

Because of the steady movement, detector receives constants signals of maxima & minima

Beams after undergoes reflection from the respective mirrors are recombined & send signal to the detector

Combined signal is called as interferogram

After that the interferogram is either transmitted or reflected to the sample cell

Samples absorbs only those IR frequencies which cause vibration within the sample molecules

The signal is transmitted to the detector where it gets measured

The coded signal were decoded by using computer Technique is called as Fourier Transformation

ADVANTAGES

Filtration of radiation from the source is not required

The data can be stored and reanalyzed

Enhanced frequency reproducibility

Enhanced frequency resolution

Less time consuming

DISADVANTAGES

Expensive

Required precision for mirror movement

Detection of the sample is influenced by water vapour, path length & chemical interference

APPLICATIONS

Opaque or cloudy samples

Trace analysis of raw materials or finished products

Kinetics reactions on the microsecond time-scale

Analysis of chromatographic and thermogravimetric sample fractions

REFERENCES Instrumental methods of chemical analysis; Gurdeep R. Chatwal;

Page no: 2.41-2.53

Pharmaceutical analysisO.V.K.ReddyPage no:1.681.72

 Introduction to FTIR Spectrometry : www.thermonicolet.com  Principles of instrumental analysis;

2nd editionDougles skoog & Donald .M.WestPage no:210-219