Ftir (fourier transform infra red spectroscopy)

PHARMACEUTICAL INSTRUMENTS

1. Presented By Aqeela Raza M.Phil. pharmaceutical chemistry University of Lahore

2. FTIR Fourier Transform InfraRed spectroscopy

3. Chemical IR spectroscopy was emerged as a science in 1800 by Sir William Herschel Firstly most IR instrumentation was based on prism or grating monochromators Michelson invented interferometer in 1881 In 1949 Peter Fellgett obtained the first IR spectrum by using FTIR spectrometer In 1960s commercial FTIR spectrometers appeared History FTIR spectroscopy

4. Terminologies Infrared Spectroscopy – the study of the interaction of infrared light with matter. Infrared Spectrometer – an instrument that measures an infrared spectrum.

5. IR spectroscopy Introduction In infrared spectroscopy , infrared light passes through a sample and certain frequencies of the light are absorbed by the chemical bonds of the substance, leading to molecular vibrations The frequencies and intensities of absorbed infrared light depend on the specific bond strengths and atoms of that molecule, and the absorption pattern (called a spectrum) is unique for each material

6. MODES OF VIBRATIONS Bending vibrations Stretching vibrations Vibration or oscillation along the line of bond Change in bond length Symmetrical stretching Asymmetrical stretching Vibration not along the line of bond Bond angle is altered In plane bending Out plane bending

7. a) Symmetrical stretching: 2 bonds increase or decrease in length simultaneously. H H C STRECHING VIBRATIONS

8. b) Asymmetrical stretching I n this, one bond length is increased and other is decreased. H H C

9. a) In plane bending Scissoring: 2 atoms approach each other Bond angles are decrease H H C C Bending vibrations

10. a) In plane bending Rocking: Movement of atoms take place in the same direction. H H C C

11. b) Out plane bending i . Wagging: 2 atoms move to one side of the plane. They move up and down the plane. Twisting: One atom moves above the plane and another atom moves below the plane. H H C C H H C C Bending vibrations

12. I nfrared spectrum example

13. FTIR SPECTROSCOPY Fourier transform infrared spectroscopy ( FTIR ) is a technique which is used to obtain an infrared spectrum of absorption or emission of a solid, liquid or gas.

14. FTIR - Fourier Transform Infrared - spectroscopy analysis and testing identifies chemical compounds FTIR offers quantitative and qualitative analysis for organic and inorganic samples . Fourier Transform Infrared Spectroscopy (FTIR) identifies chemical bonds in a molecule by producing an infrared absorption spectrum . The spectra produce a profile of the sample, a distinctive molecular fingerprint that can be used to screen and scan samples for many different components . FTIR is an effective analytical instrument for detecting functional groups and characterizing covalent bonding information. 

15. FTIR can be used with other molecular spectroscopy techniques such as Gas Chromatography - Mass Spectrometry (GC/MS), Liquid Chromatography - Mass Spectrometry (LC/MS), UV/Vis spectroscopy etc FTIR combined with these techniques provides complementary data regarding a molecule's molecular structure. 

16. INSTRUMENTATION 1.Radiation Sources Black-body radiation   Nernst filament Globar (Si-C) Ni-Cr wire Heated ceramic Mercury lamp

17. The Interferometer (Interference meter ) measures the interference pattern between two light beams. interferometer splits the single light beam into two light beams by beam splitter. The interferometer then causes the two light beams to travel different paths, After the two light beams have traveled their different paths they are recombined into one beam, and then the light beam leaves the interferometer

18. Design of interferometer There are a number of interferometer designs used by FTIR manufacturers. The oldest and the most common type of interferometer in use today is the Michelson interferometer. It is named after Albert Abraham Michelson, who first built his interferometer in the 1880s and went on to win a Nobel Prize in Physics for the discoveries he made with it.

19. STRUCTURE OF INTERFEROMETER The Michelson interferometer consists of four arms The top arm is the infrared source and a collimating mirror to collect the light from the source and make its rays parallel The bottom arm of the Michelson interferometer contains a fixed mirror Right arm of the interferometer, which contains a moving mirror which is capable of moving left and right The left arm of the interferometer contains the sample and detector At the heart of the interferometer is an optical device called a beam splitter

20. B eam splitter A beam splitter is designed to Transmit some of the light and R eflect some of the light. the light transmitted by the beam splitter travels toward the fixed mirror, and the light reflected by the beam splitter travels toward the moving mirror . Once the light beams reflect from these mirrors they travel back to the beam splitter, where they are recombined into a single light beam that leaves the interferometer, interacts with the sample, and strikes the detector.

21. 3.Detectors The beam finally passes to the detector Thermal detectors transducer of radiant energy Photoconducting detectors most sensitive detectors .

22. Pyroelectric detectors much faster response time insulator material Triglycine sulphate Figure 13: pyroelectricc detector

23. 4.The Computer The measured signal is digitized and sent to the computer where the Fourier transformation takes place. Figure 14 : FTIR spectrometer

24. WORKING The light originates from the He-Ne laser Half of the light is reflected 90 degrees and hits a fixed mirror, while the other half passes through the beam splitter and hits the moving mirror The split beams are recombined, but having traveled different distances, they exhibit an interference pattern with each other As they pass through the sample, the detector collects the interfering signals and returns a plot of response v. mirror displacement known as an interferogram

25. The Sample Analysis Process Figure 15 : FTIR spectrometeranalysis process

26. Sample Preparation Sample concentrations required is from 0.1-10%.

27. SAMPLING OF SOLIDS:

28. SOLIDS RUN IN SOLUTION Solids may be dissolved in non-aqueous inert solvent and a drop of this solution is placed on an alkali metal disc and solvent is allowed to evaporate, leaving a thin film of solute (or the entire solution is placed in a liquid sample cell) which is then mounted in spectrometer. Some solvents used are chloroform, carbon tetrachloride, acetone, Cyclohexane etc.

29. SOLID FILMS If a solid is polymer resins & amorphous solids, the sample is dissolved in any reasonable volatile solvent & this solution is poured on a rock salt plate ( Nacl or KBr ) & solvent is evaporated by gentle heating .

30. MULL TECHNIQUE: In this technique a small quantity of sample is thoroughly ground in a clean mortar until the powder is very fine. After grinding, the mulling agent (mineral oil or Nujol) is introduced in small quantities just sufficient to take up the powder (mixture approximates the consistency of a paste ). The mixture is then transferred to the mull plates & the plates are squeezed together to adjust the thickness of the sample between IR transmitting windows. This is then mounted in a path of IR beam and the spectrum is run.

31. Sampling of Liquids Neat and pure liquid used solid NaCl plates most commonly employed as “windows” (NaCl does not absorb infrared light in the mid-IR region)

32. Applications of FTIR

33. Some examples of FTIR Analysis

34. Analysis of pharmaceutical compounds

35. FTIR is used in Diseases Diagnosis Recently , infrared spectroscopy has emerged as a powerful tool for characterizing tissue and disease diagnosis. The pressure -dependence parameters such as wave number, intensity and band shape provides further information about the structural changes associated with malignancy . t has also been used in diagnosis of many diseases such as cervical cancer, Parkinson’s disease, Alzheimer’s disease, kidney stone, arthritis t is also one of the approaches for diagnoses of kidney stone by examining the form of the calcium oxalate in urine

36. Gemstones Infrared spectroscopy applied to gemstones in order to distinguish natural or synthetic pieces, or even to analyze its composition, has provided an objective evidence for its characterization and has proved to be an important tool for both identification and certification purposes in commercial and legal practices. Emeralds, diamonds, topazs , aquama rines , show characteristic infrared absorptions.

37. Analysis of multilayer samples Multilayer films of polymers are also a common sample that can be analysed using mapping or imaging FTIR spectroscopy figure shows the spectra of polyethylene and polypropylene found in two layers.

38. Selected Applications of Herbal Medicine Analysis

39. Advantages of FT-IR Speed: Because all of the frequencies are measured simultaneously, most measurements by FT-IR are made in a matter of seconds rather than several minutes.

40. Advantages of FT-IR Accuracy: By using FTIR no external calibration is required and gives accurate results . FTIR has a laser beam which keeps the FTIR instrument accurately calibrated.

41. Advantages of FT-IR FTIR can identify even small concentrations of contaminants.

42. Advantages of FT-IR Mechanical breakdown is less compared to other instruments because the mirror which is attached in the interferometer is the only moving part in FTIR.

43. References Fundamentals of Fourier Transform Infrared Spectroscopy, Second Edition https:// chemistry.oregonstate.edu/courses/ch361-464/ch362/irinstrs.htm http:// onlinelibrary.wiley.com/doi/10.1002/0471266965.com107.pub2/abstract;jsessionid=DE3657EFD91C2694862044B38C47D517.f03t04 http:// chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Spectroscopy/Vibrational_Spectroscopy/Infrared_Spectroscopy/How_an_FTIR_Spectrometer_Operates http:// www.lpdlabservices.co.uk/analytical_techniques/chemical_analysis/ftir.php