FOURIER TRANSFORM INFRA TED SPECTROSCPY - FTIR

FOURIER TRANSFORM INFRA TED SPECTROSCPY - FTIR

1. F ourier T ransform I nfra R ed Spectroscopy F T - I R

2. 1 KEY ELEMENTS Introduction Principle Instrumentation Sample Preparation Data Collection Functional Group Identification Applications Advantages Limitations Conclusion Quiz

3. Introduction To FT-IR Spectroscopy 2 FT-IR is an analytical technique used to identify organic and some inorganic materials by determining the functional groups by the application of IR radiation. It could be applied for qualitative & quantitative analysis. FT-IR spectroscopy is called a "fingerprint" technique because no two different samples are known to give the same spectrum. It can be used for solid, liquid, or gaseous samples, which give spectra based on the vibrational transitions happening in the molecule.

4. Principle Of FT-IR Spectroscopy 3 Passing a beam of IR radiation through a sample, where some of the radiation is absorbed by the sample while the rest is transmitted. The transmitted radiation is then collected and analyzed by a detector. The resulting spectrum represents the amount of absorbed infrared radiation at different wavelengths, providing information about the types of chemical bonds present in the sample. Unknown materials are identified by searching the IR spectrum against a database that has a wide range of reference spectra.

5. 4 Instrumentation Of FT-IR Spectrometer IR Source Sample Compartment Interferometer Detector Interferogram Computer WAVE NUMBER (Nm) TRANSITTANCE (%) Database Identification R S IR BEAM

6. 5 IR Source: A broadband IR source. (Ex.: Globar - Nernst Glower - Halogen lamps). Sample Compartment: Where the sample is placed for analysis. Includes a holder or cell appropriate for the sample type (solid, liquid, or gas). Some sample compartments are temperature-controlled to allow analysis at different temperatures . … Instrumentation Of FT-IR Spectrometer

7. 6 Interferometer : The core of FT-IR spectrometer is the interferometer, which modulates IR beam . The most common type in interferometers is Michelson interferometer. The interferometer splits the IR beam into two paths, one for the reference and one for the sample. The beams recombine, generating an interferogram . Various mirrors and lenses are used to direct and focus the infrared radiation onto the sample and into the interferometer. Beamsplitters and retroreflectors are key components within the interferometer. … Instrumentation Of FT-IR Spectrometer

8. 7 Detector: Responsible for converting the IR radiation absorbed by the sample into an electrical signal that can be analyzed and processed to generate interferogram. Ex.: Mercury cadmium telluride (MCT) - Deuterated triglycine sulfate (DTGS). Computer: A computer controls the spectrometer and processes the interferogram data. Software allows for spectral manipulation, including baseline correction, peak identification, and spectral comparison. … Instrumentation Of FT-IR Spectrometer

9. 8 Sample preparation is a crucial step in FT-IR spectroscopy to ensure accurate and reliable analysis of various sample types. Proper handling & storage of sample is essential to avoid contamination . Regular cleaning of sample holders, windows, and accessories helps maintain the integrity of the analysis. Background spectra from the sample holder or reference material may need to be subtracted from the sample spectrum to correct for interference. Sample Preparation For FT-IR

10. 9 … Sample Preparation For FT-IR

11. 10 … Sample Preparation For FT-IR Solid Samples Preparation Techniques: 1. Direct Analysis: Some solid samples can be analyzed directly without any preparation. They are typically placed onto a sample holder, such as a diamond or zinc selenide (Zn Se) window, and analyzed as-is. 2. KBr Pellet Method: Sample is ground with powdered (KBr) to form a homogenous mixture. The mixture is then compressed into a thin pellet using a hydraulic press.

12. 11 … Sample Preparation For FT-IR … Solid Samples Preparation Techniques: 3. Mulling Technique: Sample is mixed with a non-reactive, IR-transparent liquid ( Nujol ) forming a paste. This paste is spread onto an IR-transparent substrate as KBr window, to form a mull. This method is useful for samples that are not soluble in common solvents. 4. Thin Film Method: By pressing sample between two IR-transparent plates to create a uniform, thin film. Suitable for samples that are soluble in volatile solvents or can form stable films.

13. 12 … Sample Preparation For FT-IR … Solid Samples Preparation Techniques: 5. Attenuated Total Reflectance (ATR): ATR accessories allow for the direct analysis of solid samples without the need for extensive sample preparation. The sample is placed in contact with a crystal surface, and IR radiation penetrates the sample, providing information about its composition. This method is ideal for samples with surface-sensitive properties or those that cannot be easily prepared as thin films or pellets.

14. 13 … Sample Preparation For FT-IR Liquid Samples Preparation Techniques: 1. Thin Film Method: Sandwiching sample between two IR-transparent plates to create a thin film. Suitable for samples that are soluble in volatile solvents or can form stable films. 2. Evaporation Method: Evaporating sample in room temperature till dryness to form a thin film or residue. This method is useful for volatile liquid samples or those that are not compatible with the thin film method.

15. 14 … Sample Preparation For FT-IR Gas Samples Preparation Techniques: 1. Gas Cell Method: Introduced sample into a sealed gas cell with IR-transparent windows. The cell is then placed in the sample compartment of the FT-IR spectrometer. This method is suitable for analyzing gases or volatile compounds in the gas phase. 2. Direct Analysis: Samples introduced directly into the sample compartment of the FTIR spectrometer. The sample is analyzed as-is without any additional preparation.

16. IR beam directed through the sample which divided into two paths, one interacts with the sample, while the other serves as a reference. The two beams recombine, resulting in the interferogram detected by the detector. The interferogram is Fourier-transformed to be converted from the time domain to the frequency domain and the result is an IR spectrum. 15 Data Collection In FT-IR The IR spectrum is displayed graphically as a plot of transmittance vs frequency. The processed spectrum is stored as a reference for future analysis Software manipulates & analyzes the spectrum.

17. 16 There are several software available for controlling, processing, and analyzing data obtained from FT-IR spectroscopy (Ex.: Omnic ™ - Spectra Manager™). Software choice depends on instrument compatibility & analysis requirements. Quality control measures, such as instrument calibration and validation, are essential to ensure the accuracy and reliability of the collected data. Regular performance checks and calibration using reference materials help maintain instrument performance and data integrity. … Data Collection In FT-IR

18. 17 Functional group identification in FT-IR spectroscopy is a fundamental aspect for the determination of the chemical composition and structure of compounds. FT-IR spectra show absorption bands at specific frequencies due to the vibration of chemical bonds within the molecule. corresponding to specific functional groups present in the sample. By comparing the positions and intensities of absorption bands in the sample spectrum to reference spectra or literature data, functional groups can be identified. Functional Group Identification In FT-IR

19. 18 Each compound exhibits a unique "fingerprint" of the spectrum, which can be used for compound identification and differentiation. The following table shows the functional groups identified by the data collected from the FT-IR spectrum of samples of Aerva Lanata leaves. … Functional Group Identification In FT-IR

20. 19 Applications Of FT-IR Spectroscopy

21. 20 Medical Researches: Identify biomolecules, such as lipids, proteins, carbohydrates, and nucleic acids, within biological specimens. Also can be used for disease diagnosis, tissue pathology, and drug distribution studies. Pharmaceutical Industry: In quality control to analyze drug substances, formulations, and packaging materials, detect impurities, assess drug stability, and ensure product quality and compliance with regulatory standards. Chemical Analysis: widely used for qualitative and quantitative analysis of chemical compounds as it can identify functional groups & molecular bonds. … Applications Of FT-IR Spectroscopy

22. 21 Environmental Monitoring: In air quality monitoring, water quality assessment, and soil analysis. It can detect pollutants, contaminants & hazardous substances in environmental samples assessing their impact on ecosystems. Food & Agriculture: It can detect food adulteration, identify nutritional components, assess food spoilage, and monitor agricultural products for pesticides, toxins, and contaminants. Forensic Sciences: Identifying trace evidence, analyzing fibers, paints, and detecting drugs, explosives, and toxins aiding in criminal investigations. … Applications Of FT-IR Spectroscopy

23. Advantages Of FT-IR Spectroscopy 22 Supports quantitative analysis providing accurate concentration measurements. Versatile and can analyze various sample types, including solids, liquids, gases Rapid data acquisition compared to dispersive IR spectroscopy techniques. Highly sensitive, can detect trace amounts of analytes, (suites low concentrations or quantities samples). Covers a broad spectral range, allow analysis of wide variety of functional groups. Non-destructive, allows analysis of samples without altering chemical or physical properties, (so suites valuable materials).

24. Limitations Of FT-IR Spectroscopy 23 Data interpretation can be a challenge for complex samples with overlapping bands. Can’t detect atoms or monoatomic ions as no chemical bonds. Can’t detect molecules comprised of two identical atoms such as N 2 or O 2 . Aqueous solutions are difficult to be analyzed as water is a high IR absorbent.

25. 24 FT-IR spectroscopy stands as a cornerstone technique in the realm of analytical chemistry and material science. Its versatility, coupled with its ability to provide detailed molecular information, renders it indispensable across a broad spectrum of applications. FT-IR spectroscopy offers more advantages, including high sensitivity, wide spectral range, rapid data acquisition & versatility in sample analysis. It facilitates qualitative and quantitative analysis of diverse sample types, ranging from solids and liquids to gases, without necessitating extensive sample preparation. Conclusion

26. 25 Moreover, FT-IR spectroscopy enables the identification of functional groups, structural elucidation, and characterization of chemical compositions, aiding research and development efforts in various industries. However FT-IR spectroscopy limitations, it remains a fundamental and indispensable tool for scientific research, quality control, and problem-solving across disciplines, contributing to advancements in fields such as pharmaceuticals, environmental and materials sciences. … Conclusion

27. Choose the correct answer: 1- In FT-IR spectroscopy, all of the following are sample preparation techniques EXCEPT: Pelletizing with KBr Dissolving in water Attenuated Total Reflectance (ATR) Thin film deposition 2- Which of the following is a limitation of FT-IR spectroscopy? High sensitivity to water Limited spectral range Inability to analyze organic compounds Low spatial resolution 3- Which of the following is NOT advantage of FT-IR spectroscopy? Rapid data acquisition. Allows analysis of sample without altering its properties. Can detect atoms or monoatomic ions. Highly sensitive, can detect trace amounts of analytes. 26 4- FT-IR spectra show absorption bands at specific frequencies due to chemical bonds: Break down Forming Vibration Converting 5- In FT-IR spectroscopy, the term "Fourier Transform" refers to: Conversion of time-domain data to frequency-domain data Conversion of frequency-domain data to time-domain data Amplification of signal strength Manipulation of spectral peaks 6- In FT-IR spectrometer, the component splits the IR beam is: Detector Monochromator Sample compartment Interferometer QUIZ

28. True or False: 1- FT-IR stands for "Fast Transmission Infrared Spectroscopy.“ 2- FT-IR spectroscopy can be applied for both qualitative and quantitative analysis of samples. 3- FT-IR spectroscopy is suitable for analyzing liquid & gas samples only without solids. 4- FT-IR spectroscopy can provide information about the presence of functional groups in a sample based on characteristic absorption bands. 5- FT-IR spectroscopy is applied to detect pollutants & contaminants in environmental samples assessing their impact on ecosystems. 6- Instrument calibration and validation are optional procedures in FT-IR spectroscopy. 7- The IR spectrum is displayed graphically as a plot of transmittance vs wavelength. 27 … QUIZ Choose the correct answer: 7- What aspect can pose a challenge for data interpretation in FT-IR spectroscopy when dealing with complex samples? Overlapping bands High resolution Low sensitivity Baseline correction 8- One of sampling techniques of gases in FT-IR spectroscopy is: Thin film method Condensation method Gas cell method Attenuated Total Reflectance (ATR) Choose the correct answer True or false 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 B A C C A D A C F T F T T F F

29. Hossam Khayyal & Naif Al- Wabran BY THANK YOU