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.

Fourier transform infrared spectroscopy is preferred over dispersive or filter 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 can increase sensitivity – one second scans can

be co-added together to ratio out random noise 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

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

It moves at short distance away from the beam splitter at constant speed

Light enters the spectrometer and is split by the beam splitter. The figure above shows what is referred to as the Michelson interferometer

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 analysis-II

Shahla Fatima & Ayesha ParveenPage no:3.8-3.11

  Pharmaceutical analysis

O.V.K.ReddyPage no:1.681.72

 

Introduction to Fourier Transform Infrared Spectrometrywww.thermonicolet.com  Principles of instrumental analysis;

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