1. 1. Gamal A. Hamid
2. 2. Gamal A. Hamid Toeveryone who hashelped uswith support, new books,hard / software Andoverthe internet Special thanks for THERMO Thanks 2
3. 3. Gamal A. Hamid Contents Introduction Theory of FTIR Types of vibration Instrumentation Sample preparation Accessories Advantages Applications 3
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5. 5. Gamal A. Hamid 1-Energy 2-Matter 3-Interaction Chemistry is the science of study the interaction between energy and matter Chemistry 5
6. 6. Gamal A. Hamid Spectroscopy spectroscopy is the science of study the interaction between radiation and matter 6
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8. 8. Gamal A. Hamid 1. Radiation The electromagnetic spectrum The Electric and Magnetic fields are Oscillating in single planes at right angles to each others 8
9. 9. Gamal A. Hamid Electromagnetic Radiation Energy propagated through free space or through a material medium in the form of electromagnetic waves. 9
10. 10. Gamal A. Hamid IR Radiation Electromagnetic radiation at wavelengths longer than the red end of visible light and shorter than microwaves (roughly between 1 and 100 microns). Almost none of the infrared portion of the electromagnetic spectrum can reach the surface of the Earth. Our skin emits infrared light, which is why we can be seen in the dark by someone using night vision goggles. 10
11. 11. Gamal A. Hamid No. Region Range Vibrational / Rotational Information 1 Near IR 14000 - 4000 Changes in Vibrational and rotational levels, electron transitions 2 Mid-IR 4000 - 400 Changes in fundamental Vibrational levels of most molecules 3 Far-IR 400 - 20 Rotational energy level changes IR Regions 11
12. 12. Gamal A. Hamid The Tested samples Paints , Pigments, Polymers, Drugs Food additives ,Air polluents, Plasticizers, Rubber and Plastics 2. Matter 12
13. 13. Gamal A. Hamid 3. Interaction Molecular Excitation Molecules are formed by the combination of two or more atoms. Unlike atoms, molecules can be subdivided to individual atoms. Atomic Excitation An atom is smallest particle in an element that has the properties of the element. In nuclear, atomic, and molecular systems, the excited states are not continuously distributed but have only certain discrete energy values. Thus, external energy (excitation energy) can be absorbed only in correspondingly discrete amounts. 13
14. 14. Gamal A. Hamid 3. Interaction As an electromagnetic field propagates through a sample, there will be a certain average excited state population that will have a coherent and an incoherent component. At all times, the excited state has the option of simply relaxing spontaneously and emitting a photon. Energy of molecule (E total ) E total = 4 E 1. E Electronic motion 2. E Rotational motion 3. E Translational motion 4. E Vibrational motion 14
15. 15. Gamal A. Hamid Number of motions Degree of freedom for polyatomic molecules No. Motion Linear Non-linear 1 Translation 3 3 2 Rotational 2 3 3 Vibrational 3N-5 3N-6 4 Total 3N 3 N Where N is the number of atoms 15
16. 16. Gamal A. Hamid I. Electronic motion The electronic component is linked to the energy transitions of electrons as they are distributed throughout the molecule, which is the result of the absorption of energy within the NIR regions. 16
17. 17. Gamal A. Hamid II. Rotational motion Rotational energy, which gives rise to its own form of spectroscopy, is observed as the tumbling motion of a molecule, which is the result of the absorption of energy within the microwave and NIR regions. 17
18. 18. Gamal A. Hamid III. Translational motion The translational energy relates to the displacement of molecules in space as a function of the normal thermal motions of matter. 18
19. 19. Gamal A. Hamid IV. Vibrational motion The absorption of the electromagnetic radiation by matter leads to many Type of vibrations 1. The dipole moment of the molecule must change during the vibration. 2. Homonuclear diatomic molecules such as Hydrogen (H2), Nitrogen (N2) and Oxygen (O2) no infrared absorption is observed because its dipole moment remains zero. 19
20. 20. Gamal A. Hamid Molecular vibrations 1. The positions of atoms in a molecules are not fixed. 2. The Vibrational corresponds to the absorption of energy by a molecule 3. Main categories of stretching and bending. 20
21. 21. Gamal A. Hamid Stretching Change in inter-atomic distance along bond axis Stretching absorptions usually produce stronger peaks than bending 21
22. 22. Gamal A. Hamid Bending Change in angle between two bonds. 1. Twisting 2. Rocking 3. Wagging 4. Scissoring Twisting Rocking Wagging Scissoring 22
23. 23. Gamal A. Hamid IR Chart This Chart is a result of interaction bet. IR-radiations and matter. 23
24. 24. Gamal A. Hamid Four regions of Chart 1. 3700 2500 cm-1 Single bonds to hydrogen 2. 2300 2000 cm-1 Triple bonds 3. 1900 - 1500 cm-1 Double bonds 4. 1400 - 650 cm-1 Single bonds (other than hydrogen) 24
25. 25. Gamal A. Hamid Fingerprint region 1- The region to the right-hand side of the diagram (from about 1650 to 500 cm-1) 2- Usually contains a very complicated series of absorptions 3- Contains peaks due to bending vibrations 4- It is rarely possible to assign a specific peak to a specific group. 25
26. 26. Gamal A. Hamid Properties of peaks 1. Intensity (weak, medium or strong), 2. Shape (broad or sharp), and 3. Position (cm-1) in the spectrum. 26
27. 27. Gamal A. Hamid Peaks Properties Absorbance%TransmissionDesignation >1.3 ~0.6 ~0.3 ~0.2 ~0.1 ~0.07 ~0.02 ~0.01 98 VVS VS S M MW W VW VVW 27
28. 28. Gamal A. Hamid Definitions Wavelength The wavelength is the distance between two identical points on two adjacent identical waves in a beam. Wave number Wave number is defined as the reciprocal of the wavelength expressed in cm. Units are cm-1. Wave numbers are normally the units along the X-axis in Infrared spectra. 28
29. 29. Gamal A. Hamid Fourier Transform Infrared Spectroscopy FTIR A method of obtaining an Infrared spectrum by measuring the interferogram of a sample using an interferometer, then performing a Fourier Transform upon the interferogram to obtain the spectrum. 29
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31. 31. Gamal A. Hamid Instrumentation Source Laser Interfero meter Detector 31
32. 32. Gamal A. Hamid 1. Source The source The Ever Glo energy source can be used to collect data in the mid-and far-infrared spectral ranges. 32
33. 33. Gamal A. Hamid 2. Laser Purpose The Laser source produce a single beam with a definite wave length for internal calibration. 33
34. 34. Gamal A. Hamid 3. Interferometer The heart of the spectrometer An device in which two or more radiation beams interfere with each other after passing through different optical paths. The interferometer produces a unique type of signal which has all of the infrared frequencies encoded into it. The output is an interferogram or interference record. The two domains of Distance and Frequency are inter convertible by the mathematical method of Fourier transformation. 34
35. 35. Gamal A. Hamid Michelson Interferometer The Michelson interferometer, which is the core of FTIR spectrometers, is used to split one beam of light into two so that the paths of the two beams are different. Then the Michelson interferometer recombines the two beams and conducts them into the detector where the difference of the intensity of these two beams are measured as a function of the difference of the paths. 35
36. 36. Gamal A. Hamid An optical device causing two beams of light to travel different distances to produce an optical path difference. This allows constructive and destructive interference to occur, and changing the optical path difference allows the measurement of an interferogram. consists of A. beam splitter semi-reflecting B. fixed mirror C. moving mirror 36
37. 37. Gamal A. Hamid A. Beam Splitter The beam splitter is made of a special material that transmits half of the radiation striking it and reflects the other half. Radiation from the source strikes the beam splitter and separates into two beams. One beam is transmitted through the beam splitter to the fixed mirror and the second is reflected off the beam splitter to the moving mirror. The fixed and moving mirrors reflect the radiation back to the beam splitter. Again, half of this reflected radiation is transmitted and half is reflected at the beam splitter, resulting in one beam passing to the detector and the second back to the source. 37
38. 38. Gamal A. Hamid Mirrors B. Stationary Mirror The stationary mirror in an FTIR interferometer is nothing more than a flat highly reflective surface. C. Moving Mirror There is present only one moving part in an FTIR spectrometer, its oscillating mirror. Air bearings are used in FTIR spectrometers because of the higher speed that the oscillating mirror is required to move at. 38
39. 39. Gamal A. Hamid 4. Detector DTGS Deuterium tri glycine sulphat in a temperature resistance alkali halide window MCT Mercury cadmium telluride (sensitive work) The detector has to be coated to liquid nitrogen The output from the detector goes to a preamplifier where it is converted into a voltage signal varying with time. 39
40. 40. Gamal A. Hamid Calibration Polystyrene IUPAC: Tables of wave numbers for the calibration of IR spectrometers Wave number Intensity 3027.1 9 2924 10 2850.7 7 1944.0 3 1871.0 3 1801.6 3 1601.4 9 1583.1 5 1495 10 1454 10 Wave number Intensity 1353 5 1332 5 1282 3 1181.4 4 1154.3 4 1069.1 6 1028.0 8 906.7 3 842 3 752 10 698.9 10 40
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42. 42. Gamal A. Hamid Sample Preparation Infrared Reflectance Spectroscopy 1. Attenuated Total Reflection 2. Diffuse Reflectance 3. Specular reflectance Infrared Transmission Spectroscopy 1. Transmission Solid 2. Transmission liquid 3. Transmission gas I. Transmission radiation passes through a sample II. Reflectance Radiation reflected from the sample surface. 42
43. 43. Gamal A. Hamid Sample Preparations Transmission Reflectance 43
44. 44. Gamal A. Hamid I. Infrared Transmission Spectroscopy 1. Transmission Solid 2. Transmission liquid 3. Transmission gas 44
45. 45. Gamal A. Hamid 1. Transmission Solid 1. 2 mg sample powder. 2. 300 mg KBr( spectroscopic grade) into an agate mortar. 3. Grind the powders together until it become like fine flour. 4. Transfer the ground mixture into the cylinder bore. 5. Place the die assembly into a hydraulic press. 6. Increase pressure in the press to 15 tons . Potassium Bromide disk 45
46. 46. Gamal A. Hamid 7. Carefully release the vacuum, and remove the die from the press. 8. Dismantle the die, and transfer the KBr disk to a spectrometer disk holder Avoid touching the faces of the disk. 9. Mount the disk holder in the spectrometer. 46
47. 47. Gamal A. Hamid 1. Uneven distribution in powder in die 2. Too much sample 3. Too much KBr powder 4. Poorly dispersed sample 5. Water in die 6. Pressed at too low pressure or at too low time If the disk is not translucent 47
48. 48. Gamal A. Hamid The appearance of the spectra depends on 1. The relative amounts of surface reflection (particle size) 2. Radiation that has penetrated the sample 48
49. 49. Gamal A. Hamid The flattened turning point and do not reach 0 % T, this is caused by a poorly dispersed sample or holes in the disk. Sloping baseline is usually due to a poorly dispersed sample. 49
50. 50. Gamal A. Hamid 2. Transmission Liquid The simplest and most common method of sample preparation A drop of the sample is placed between two potassium bromide or sodium chloride circular plates, This produce a thin capillary film. The plates are then placed in a holder ready for analysis. 50
51. 51. Gamal A. Hamid 1. The sample is ground using an agate mortar and pestle to give a very fine powder 2. A small amount is then mixed with Nujol to give a paste . 3. Several drops of this paste are then applied between two sodium chloride plates (these do not absorb infrared in the region of interest). 4. The plates are then placed in the instrument sample holder ready for scanning. Nujol Mull 51
52. 52. Gamal A. Hamid The infrared spectrum of a thin film can be easily obtained by placing a sample in a suitable holder, such as a card with a slot cut for the sample window. This method is often used for checking the calibration of an instrument with a polystyrene sample Thin film 52
53. 53. Gamal A. Hamid Liquid Cells Ideal for the quantitative analysis of hydrocarbons in water and soil samples or for the analysis of additive content in polymers after extraction. Sample extracts are easily transferred to the quartz cells for infrared analysis. For analysis of polymer additives after extraction Highest quality quartz cells for clear infrared spectral transmission and optimized result 53
54. 54. Gamal A. Hamid 3.Transmission Gas Use of a cylindrical gas cell with windows at each end composed of an infrared inactive material such as KBr, NaCl or CaF2. The cell usually has an inlet and outlet port with a tap to enable the cell to be easily filled with the gas to be analyzed. 54
55. 55. Gamal A. Hamid Advantages of Transmission 1. Does not require an additional accessories. 2. Used in the collection of many reference library spectra. 3. Ideal for quantitative measurements. 4. Does not require extensive training. 55
56. 56. Gamal A. Hamid II. Infrared Reflectance Spectroscopy 1. Attenuated Total Reflection 2. Diffuse Reflectance 3. Specular reflectance 56
57. 57. Gamal A. Hamid 1. Attenuated Total Reflection The beam is directed onto optical dense crystal , internal reflectance create waves that extend to the sample in contact with crystal surface. Horizontal Vertical 57
58. 58. Gamal A. Hamid HATR Used in the analysis of liquid, semi-liquid materials and a number of solids. HATRs feature a constant and reproducible effective path length and are well suited for both qualitative and quantitative applications. In general, sampling is achieved by placing the sample onto the HATR crystal generally eliminating sample preparation. 58
59. 59. Gamal A. Hamid 2. Diffuse Reflectance Sample cup filled with mixture of sample and KBr IR radiation interact with sample particles, then reflecting External reflectance off their surfaces causing diffuse and scattering of radiation. standard 11 mm diameter cup, a micro 4 mm diameter cup, and tilted cups. The tilted cups allow for collection of total reflectance, diffuse and specular components. In addition, an abrasive sampler, 12 mm diameter, can be used with Diabrase pads to allow quick and easy sample preparation of intractable solids. 59
60. 60. Gamal A. Hamid 3. Specular reflectance The principle of specular reflectance depending on the change of the refractive index of sample which varies with frequency of light to which it is expose. When reflected light is scattered by the sample it is called diffuse reflection. When it is reflected directly, it is called specular reflection 60
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62. 62. Gamal A. Hamid Agate Pestle and Mortar Agate Mortar 4 cm diameter bowl and Pestles are the ideal tool for manually grinding solid samples with an appropriate mull agent (such as KBr powder, Nujol, or Fluorolube) in preparation for mull FTIR transmission analysis, diffuse reflectance, and KBr pellet press applications. Pure agate is non-absorbing in the infrared spectroscopic region. Specac Mortar and pestle sets are available at 40 mm diameter as standard. 62
63. 63. Gamal A. Hamid Pellet Dies These are particularly well suited for the preparation of solid KBr pellets for FTIR molecular spectroscopic analysis These Pellet Dies produce circular pellets in sizes from 5 mm to 40 mm diameter as standard 63
64. 64. Gamal A. Hamid Hydraulic Press Manual Hydraulic Press is available in 15 and 25 ton load configurations. The press has a compact, small footprint design making it ideal for bench-top and glove box laboratory applications. With a rigid steel construction, and protective safety shield as standard, this laboratory hydraulic press is particularly well-suited for FTIR KBr pellet press. 64
65. 65. Gamal A. Hamid Transmission Sampling Kit Comprehensive Transmission Sampling Kit (CTS) Gases, Solids and Liquids. Includes: Sample preparation tools, mull liquids, cells. windows and cell holders required for preparation and analysis of gas, solid and liquid samples. 65
66. 66. Gamal A. Hamid Smart accessories 1. High speed and ease to use. 2. Highest quality data and the greatest degree of flexibility. 3. Automatic setting of accessory. 4. More reproducible and reliable. 5. Samples analyzed in their natural status. 6. Excellent for thick samples. 66
67. 67. Gamal A. Hamid Heating Gas cell 1. Analyzes gaseous samples and vapors from room temperature to250 C. 2. The cell is an evacuable stainless steel chamber with an injection septum sample introduction port. 3. It is heated by a low voltage heater surrounding the body. 4. The temperature can be measured with a thermocouple passing through a vacuum tight seal into the gas cavity. 67
68. 68. Gamal A. Hamid Advanced Liquid Transmission Cells Advanced Liquid Transmission Cells in sealed, demountable, static, and flow configurations to allow liquid samples to be studied at temperatures other than ambient. A choice of window materials allow for spectral analysis in the UV, Visible, NIR, and IR. 68
69. 69. Gamal A. Hamid The High Temperature/High Pressure Cell 1. The High Temperature/High Pressure Cell is a water cooled, that can operate at up to 800 C and 1000 psi 2. It also allows the study of vapors generated by the thermal decomposition of a sample. 69
70. 70. Gamal A. Hamid Selector Environmental Chamber 1. This accessory allows for the study of diffusely reflecting solid samples in a controlled atmosphere ranging from ambient temperature to 500 C, and vacuum (10-3 Torr) to 500 p.s.i. pressure. 2. The standard chamber window is ZnSe, which gives a good balance between IR transmiss 70
71. 71. Gamal A. Hamid The Mill 1. The mill is used for the production of the uniformly small and consistent particle size necessary for successful preparation of KBr sample pellets. 2. It can also be used in preparing samples for diffuse reflectance spectroscopy. 71
72. 72. Gamal A. Hamid The GladiATR Vision Sampling tool which couples small area infrared analysis with simultaneous viewing. Samples are placed face down and positioned on the diamond crystal while its image is projected in real-time on the LCD screen. Finding and optimizing the sample placement for specific analysis areas is easy and fast! Analysis of thick or non-transparent samples is no problem because viewing is through the diamond crystal. 72
73. 73. Gamal A. Hamid Infrared Window Materials PropertiesRangeMaterialNo. Soft crystal- Insoluble in water22,000-286AgBr1 Soluble-Low cost-Good transmission40,000-400KBr2 Soluble-Low cost-Good transmission40,000-625NaCl3 Hard crystal- Insoluble in water5,500-600Ge4 73
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75. 75. Gamal A. Hamid 1. Smart Searching Spectral databases have become an integral part of the use of FT-IR equipment. With spectral libraries, Both software packages allow you to create your own user libraries as a standard feature. 75
76. 76. Gamal A. Hamid 2. Smart Interpretation Built-in spectral interpretation tools. These tools provide functional group information for your spectrum. Information on over 100 common functional groups 76
77. 77. Gamal A. Hamid 3. Easy Maintaining You can minimize downtime and service costs on your IR Series system. User-replaceable components on your IR Series system will include: Source Laser Detector Mirrors Power supply Desiccant 77
78. 78. Gamal A. Hamid 4. FT-IR microscope Optional external beam capability for the Centaurus TM FT-IR microscope. This purpose-built system is ideal for routine analysis of samples as small as 50 microns. 78
79. 79. Gamal A. Hamid 5. Smart Accessories Powder or liquid sampling Changeable crystals 79
80. 80. Gamal A. Hamid 6. Easy Sampling All IR Series spectrometers include a standard transmission accessory holder. In addition, the sample compartment come ready for Foundation Series TM ATR Swap- Top TM modules. for the most flexibility in FT-IR accessory sampling techniques. 80
81. 81. Gamal A. Hamid 7. Isolated optical system The cover reduces the environmental effects on your spectra 81
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83. 83. Gamal A. Hamid Interpretation of IR chart 1. Look for the carbonyl C::O strong band at 1820-1660 cm- 2. This band is usually the most intense absorption band in a spectrum. 3. If no C::O band is present, check for alcohols . 4. for the broad OH band near 3600-3300 cm-1 and a C-O absorption band near 1300-1000 cm-1. 83
84. 84. Gamal A. Hamid 5. If a C::O is present you want to determine if it is part of an acid, an ester, or an aldehydes or ketones. 6. (Acid ) O-H is present There will also be a C-O single bond band near 1100-1300 cm-1. Look for the carbonyl band near 1725 -1700 cm-1. 7. (Ester) Look for C-O absorption of medium intensity near 1300-1000 cm-1. There will be no OH 8. And continue to interpretate the compound 84
85. 85. Gamal A. Hamid Interpretation of IR chart Using the software you can interpretate most of organic compounds 85
86. 86. Gamal A. Hamid IR Chart 86
87. 87. Gamal A. Hamid Tables 1 Frequency range, cm-1Compound TypeBond 2960-2850(s) stretch AlkanesC-H 1470-1350(v) scissoring and bending 3080-3020(m) stretch AlkenesC-H 1000-675(s) bend 3100-3000(m) stretchAromatic Rings C-H 870-675(s) bend Phenyl Ring Substitution Bands 87
88. 88. Gamal A. Hamid Tables 2 Frequency range, cm-Compound typeBond 2260-2100(w,sh) stretchAlkynesCC 1600, 1500(w) stretchAromatic RingsC=C 1260-1000(s) stretch Alcohols, Ethers, Carboxylic acids, Esters C-O 1760-1670(s) stretch Aldehydes, Ketones, Carboxylic acids, Esters C=O 88
89. 89. Gamal A. Hamid Air Pollution EPA Said The FTIR technology shows promise since it has the capability to measure more than 100 of the 189 Hazardous Air Pollutants 89
90. 90. Gamal A. Hamid Solvents analyses ATR-FTIR Solvents Library : 630 selected spectra solvents selected from the Aldrich 90
91. 91. Gamal A. Hamid Drugs analyses ATR-FTIR Pharmaceuticals, Drugs & Antibiotics Library 1338 selected spectra 1. Active substances . 2. Aids commonly used in pharmaceutical industry . 91
92. 92. Gamal A. Hamid Polymers analyses ATR-FTIR Polymers and Polymer Additives Library: 650 selected spectra 1. Polymers. 2. Polymer additives. 3. Plasticizers. 4. Packing materials. 92
93. 93. Gamal A. Hamid Foods analyses ATR-FTIR Food Additives and Food Packaging Library 2083 selected spectra 1. Substances added to food. 2. Substances regulated by the FDA. 93
94. 94. Gamal A. Hamid Pesticides analyses ATR-FTIR Pesticides Library : 1219 selected spectra Pesticides including insecticides. Herbicides, algaecides and fungicides. 94
95. 95. Gamal A. Hamid 95 gamal_a_hamid@hotmail.com