Date post: | 04-Jun-2018 |
Category: |
Documents |
Upload: | ricardo-leon-mora-basto |
View: | 226 times |
Download: | 0 times |
of 89
8/13/2019 FT IR Grundl. Seminar
1/89
FTIR SeminarFTIR SeminarChapter 1 Principles and Fundamentals of Infrared Spectroscopy
Chapter 2 Principles of FTIR
Chapter 3 Standard Data Processing Features
Chapter 4 Transmittance Techniques
Chapter 5 Reflectance Techniques
Chapter 6 Quantitative Analysis (Optional Software)
Chapter 7 Infrared Spectrum Analysis Techniques
8/13/2019 FT IR Grundl. Seminar
2/89
JASCO FTIR Seminar Chapter 1Principles and Fundamentals of Infrared Spectroscopy
Principles and Fundamentalsof Infrared Spectroscopy
FTIR SeminarChapter 1
8/13/2019 FT IR Grundl. Seminar
3/89
FTIR seminar
%T
Wavenumber [cm-1]
0
100
20
40
60
80
4000 4002000 1000
Chapter 1-1Infrared absorption spectrumPrinciples and Fundamentals of Infrared Spectroscopy
Infrared absorption spectrum
8/13/2019 FT IR Grundl. Seminar
4/89
FTIR seminar
0.05A=50XU
1m
1mm=1000m
2.5m
0.7m=700nm
500A
400nm
1XU
Microwaves
Far infrared
Near infrared
Near UV
Far-UV
Radio waves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays
Cosmic rays
10cm-1
14000cm-1
400cm-1
4000cm-1
2000A
25m
Chapter 1-2Types of Electromagnetic RadiationPrinciples and Fundamentals of Infrared Spectroscopy
Types of Electromagnetic Radiation
8/13/2019 FT IR Grundl. Seminar
5/89
FTIR seminar
Electronic energy Visible light and ultraviolet energy
Vibrational energy Infrared energy
Rotational energy Near-infrared energy
Molecular energy = electronic energy
+ vibrational energy
+ rotational energy
Molecular energy level
Excited
state
Ground
state
Emission of energy
as heatLight
absorptionE
E
.=..=..=.
Chapter 1-3Interaction between Molecular Dynamics and Light
Interaction between Molecular Dynamics and Light
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
6/89
FTIR seminar
Spring between two spheres
Infrared light and a molecule only interact when the dipole moment of the molecule
changes due to vibration
Heteronuclear diatomic molecules : HCI, CO Infrared active
Chapter 1-4Molecular Vibration of Diatomic Molecules
Homonuclear diatomic molecules : O2, H2, N2, and CL2 Infrared inactive
Molecular Vibration of Diatomic Molecules
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
7/89
FTIR seminar
The Vibrational Frequency of a diatomic molecule for which the absorption position,
bond strength = spring strength, can be expressed by the following equation
f : strength constant (bond constant and bond order)
m and m : mass number of atom
C: Speed of light
Chapter 1-5Vibrational Frequency of Diatomic Molecules
Vibrational Frequency of Diatomic Molecules
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
8/89
FTIR seminar
(1) Symmetric stretching vibration
Infrared inactive
(2) Asymmetric stretching vibration
2349cm-1
(3) Deformation vibration
667cm-1
CO2: linear molecule
Degeneracy
O C O
O OC
CO O
O OC
Chapter 1-6-1Normal Frequency of Triatomic Molecules (CO2)
Normal Frequency of Triatomic Molecules (CO2)
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
9/89
FTIR seminar
H2O : nonlinear molecule(1) Symmetric stretching vibration
(2) Asymmetric stretching vibration
3652cm-1
(3) Deformation vibration
3756cm-1
1595cm-1
HH
HH
HH
O
O
O
Chapter 1-6-2Normal Frequency of Triatomic Molecules (H2O)
Normal Frequency of Triatomic Molecules (H2O)
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
10/89
FTIR seminarChapter 1-7Number of Normal Frequencies
The number of normal frequencies of a molecule consisting of n atoms can be determined by
the following calculations:
Linear molecule 3n-5
Nonlinear molecule 3n-6
Example :
3333 x 3 - 5 = 4x 3 - 5 = 4x 3 - 5 = 4x 3 - 5 = 4
3333 x 3 - 6 = 3x 3 - 6 = 3x 3 - 6 = 3x 3 - 6 = 3
Number of Normal Frequencies
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
11/89
FTIR seminarChapter 1-8Molecular Vibration of Polyatomic Molecules
Example : Acetaldehyde
Molecular Vibration of Polyatomic Molecules
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
12/89
FTIR seminarChapter 1-Absorption
9Position
O-H, N-H
C-H
- H
(C=C, C=N)
(C=O)
4000 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400Wavenumber (cm-1)
Gamma rays MicrowavesInfraredVisible lightUltravioletX-rays
(C-C, C-O, C-N)
Etc.
Absorption Position
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
13/89
FTIR seminarChapter 1-10An Example of Assignment
0
100
20
40
60
80
4000 4002000 1000
%T
Polystyrene
Polyethylene
0
100
20
40
60
80
4000 2000 1000
%T
Wavenumber[cm-1]
Wavenumber[cm-1]
C-H stretching vibration
Methylene scissoring vibration
Methylene rolling vibration
C-H
stretching
vibration of a
benzene ring
Harmonics andcombination
tones of an out-
of-plane
deformation
vibration
Skeletal
vibration of
benzene
rings
C-H out-of-plane
deformation vibration
An Example of Assignment
Principles and Fundamentals of Infrared S
400
pectroscopy
8/13/2019 FT IR Grundl. Seminar
14/89
FTIR seminarChapter 1-11Absorption Strength
Absorption strength depends on the size of deformation of the dipole moment due to vibration
Deformation of the dipole moment is large : strong absorption C=O, C-X
Deformation of the dipole moment is small: weak absorption C-C
Absorption Strength
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
15/89
FTIR seminarChapter 1-12Near-Infrared Absorption Spectrum
Principles of absorption
Harmonics or combination tones of normal frequencies
PrimarilyO-H,N-H, andC-H
Weak absorption compared to the infrared region
Spectrum shape is complex
Analysis
A recent trend is quantitative analysis by the application of Chemometrics
Main Applications
Nondestructive analysis in agriculture- and food-related fields
Near-Infrared Absorption Spectrum
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
16/89
FTIR seminarChapter 1-13Far-Infrared Spectrum
Absorption principles
Vibrations of heavy atoms and weak bonds
Example : Metals such as copper and tin
Sulfur and iodide
Coordinate bonds (complexes)
Rotation
Far-Infrared Spectrum
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
17/89
FTIR seminarChapter 1-14Conclusion of Chapter 1
(1) Region
Infrared : 4,000 to 400 cm-1
Produces information on molecular vibration and rotation
Near infrared : above 4,000 cm-1
Almost entirely harmonic peaks of normal frequencySamples containing moisture can also be measured
Introduced in the fields of processed foods and agriculture
Far-infrared : below 400 cm-1
Molecular rotation information
Metal oxides, metal compounds, and organic and inorganic metal complexes
Conclusion of Chapter 1
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
18/89
FTIR seminarChapter 1-15Conclusion of Chapter 1
(2) Analysis targets : Organic and inorganic substances
(3) State : Gas, liquid, and solid
(4) Analysis description
Qualitative analysisFunctional group analysisDetermines the existence of functional groups by
the presence of specific functional group peaks.
Pattern analysisEstimates compound materials by comparing standard spectra
Quantitative analysisThe strength (absorbance) of the absorption band
is proportional to the amount of the material.
Quantitative analysis is possible.
Conclusion of Chapter 2
Principles and Fundamentals of Infrared Spectroscopy
8/13/2019 FT IR Grundl. Seminar
19/89
JASCO FTIR Seminar Chapter 2Principles of FTIR
Principles of FTIR
FTIR SeminarChapter 2
8/13/2019 FT IR Grundl. Seminar
20/89
FTIR seminarChapter 2-1Process up to Obtaining a Spectrum
Light
sourceBackground
Sample
(B)
(S)
Transmission spectrum
(S) / (B)
4000 400
SB
Wavenumber[cm-1]
4000 400
SB
Wavenumber[cm-1]
4000 400
%T
Wavenumber[cm-1]
Interferometer
Measurement:Interfe
rogram
Fouriertransformpro
cess
Principles of FTIR
Process up to Obtaining a Spectrum
8/13/2019 FT IR Grundl. Seminar
21/89
FTIR seminarChapter 2-2Spectroscope
Light
source
InterferometerSample
chamberDetector
Electrical system
circuits
Computer
Infraredlight
Interference
waves
Absorption
(Interferogram)
Optical
signal
Electrical
signal
Signal sampling
Analog signal
Digital signal
Fourier transform
IR spectrum
Spectroscope
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
22/89
FTIR seminar
Intensity Distribution and Temperature Dependency versus Wavelength of
Black Body Radiation Energy
Chapter 2-3IR light source
2 5 2010
10
5
104
103
102
10
1
10-1
10-2
10-3
10-4
0.1 0.2 0.5 1 50 100
Wavelength ////m
6000K
4000K
2000K
1000K
500K
300K
200K
S
pectralirradiance
W
IR light source
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
23/89
FTIR seminarChapter 2-4FT Optical System Diagram
Interferometer
He-Ne gas laser
Fixed mirror
Movable mirror
Sample chamber
Light
source(ceramic)
Detector
(DLATGS)
Beam splitter
FT Optical System Diagram
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
24/89
Chapter 2-5Interference of Two Beams of Light
Fixed mirror
Movable mirror
Fixed mirror
Movable mirror
Fixed mirror
Movable mirror
Same-phase interferencewave shape
Opposite-phase
interference
wave shape
Same-phase interference
wave shape0
Movable mirror
Interference pattern of light
manifested by the optical-path
difference
Continuous phase shift
Signalstrength
(X)
-2 - 0 2
-2 - 0 2
FTIR seminar
Interference of Two Beams of Light
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
25/89
Chapter 2-6Interference Is a Superpositioning of Waves
Relationship between light source spectrum and the signal output from interferometer
(a) Monochromatic light
(b) Dichroic light
(c) Continuous spectrum light
All intensities are standardized.
Light source spectrum Signal output from interference wave
Time t
Time t
Time tI(t)
I
(((())))
Wavenumber
Wavenumber
Wavenumber
I
Az
Az
FTIR seminar
Interference Is a Superpositioning of Waves
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
26/89
FTIR seminarChapter 2-7Sampling of an Actual Interferogram
Interferometer interferogram
Output of a Laser interferometer
Primary interferometer interferogram that was sampled
Optical path difference x
Sampling of an Actual Interferogram
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
27/89
FTIR seminarChapter 2-8Fourier transform
4000 400
SBFourier transform
Optical path difference[x]
(Interferogram) (Single beam spectrum)
Wavenumber[cm-1]
Singlestrength
Time axis by FFT Wavenumber
Fourier transform
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
28/89
FTIR seminarChapter 2-9Detector Properties
TGS
Operates at room temperature
MCT
Operates at the temperatur
of liquid nitrogen
D
*(,
f)(cmHz
1/2
W-1)
1010
109
108
Wavenumber[cm-1]4000 600
Detector Properties
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
29/89
FTIR seminarChapter 2-10Measurement Parameters
Resolution: Fixed, qualitative analysis of liquid sample: Standard4 cm-1
Gas analysis, peak shift study, and band resolution etc: High resolution
The larger the maximum optical path difference of the interferometer, the
higher the resolution
Number of integrations: Approx. ten times normal gain
The goal is to improve the SN ratio. SN ratio improvement can be expected at
multiples of the integration count root
Apodization function: StandardCosine
Since the movable mirror can only move a certain distance,
discontinuity arises in the data. Apodization is an operation that
treats the end of the interferogram so that there is no difference in level.
Apodization is concerned with the shape of peaks
(including their sharpness and half-value width)
Zero filling: Interpolation of data (smoothes out data)
Measurement Parameters
Principles of FTIR
8/13/2019 FT IR Grundl. Seminar
30/89
JASCO FTIR Seminar Chapter 3Standard Data Processing Features
Standard Data Processing Features
FTIR SeminarChapter 3
8/13/2019 FT IR Grundl. Seminar
31/89
Chapter 3-1Standard Data Processing Features
Baseline correction : Fixes curved baselines
Extraneous peak elimination : Cuts absorption peaks for atmospheric carbon dioxide gas (CO2)
Smoothing : Reduces noise by means of computer processing
Difference spectra : Decomposition of spectra containing multiple components etc.
FTIR seminar
Peak processing : Computation of peak position, height, area, and half-value width
Ordinate axis conversion : %T Abs etc.
KM conversion : In the diffuse reflectance method, conversion of transmissivity
to the y axis proportional to temperature
KK conversion : Conversion of an abnormal spectrum affected by the sample s
refractivity to an absorption spectrum
ATR correction : Use of ATR to correct spectrum distortion
Mathematical operations : Mathematical operations for two spectra or a spectrum and constant
Differential : Differential of spectra
Others
Deconvolution: Extraction of peak positions in each band
FFT filtering: Eliminates from spectra only noise possessing a specific cycle
Data cutting: Cuts measured spectra to any wavenumber region
Curve fitting: Band decomposition
Validation: Instrument performance check
Standard Data Processing Features
Standard Data Processing Features
8/13/2019 FT IR Grundl. Seminar
32/89
Chapter 3-2Baseline Correction
Infrared light
Scattered light
Scattered light
Effect of sample refractivity
A sample containing carbon has high
refractivity
Among the effects of this refractivity is a lower
base to the right
40
100
4000 700
%T
Wavenumber[cm-1]
Property of light: Light scatters when it strikes a particle larger than its own wavelength
FTIR seminar
Relationship of particle siz
0
100
4000 400
%T
Wavenumber[cm-1]
e
Particle
Baseline Correction
Standard Data Processing Features
8/13/2019 FT IR Grundl. Seminar
33/89
Chapter 3-3Correction Example
After-correction
0
100
50
4000 400
%T
Wavenumber[cm-1]
Wavenumber[cm-1]0
100
50
4000 400
%T
FTIR seminar
Baseline Correction
Correction Example
Standard Data Processing Features
8/13/2019 FT IR Grundl. Seminar
34/89
Chapter 3-4CO2Elimination
30
100
4000 650
%T
Wavenumber[cm-1]
After-elimination
30
100
4000 650Wavenumber[cm-1]
Before-elimination
%T
CO2
FTIR seminar
When a large CO2peak appears in a spectrum,
mathematical processing is used to eliminate it.
CO2absorption peaks appear near 2,350 and 670 cm-1.
CO2Elimination
Standard Data Processing Features
8/13/2019 FT IR Grundl. Seminar
35/89
Chapter 3-5Difference Spectra
(Target component + known component) - known component = target component
Blue line: adhesive
Red line: hot-melt nylon
Adhesive - hot-melt nylon
= acrylic polymer
1.0
650
-0.1
4000
Abs
Wavenumber[cm-1]0.0
1.0
4000 650
Abs
Wavenumber[cm-1]
Temperature correction
FTIR seminar
Difference Spectra
Standard Data Processing Features
8/13/2019 FT IR Grundl. Seminar
36/89
JASCO FTIR Seminar Chapter 4Transmission Techniques
Transmission Techniques
FTIR Seminar
Chapter 4
8/13/2019 FT IR Grundl. Seminar
37/89
Solid samples
Liquid samples
KBr disk
technique
Primarily qualitative analysis of organicor inorganic substances in powder form
or that can be made into powder form
Thin-film
technique
Polymeric qualitative and quantitative
analysis for substances in film form
or that can be made into film form
Solution
technique
Primarily qualitative analysis of
substances dissolved in solvent(uses liquid cells)
Liquid film
technique
Primarily qualitative analysis of
viscous and nonvolatile substances
(sandwiched between KBr windows)
Solution
technique
Primarily qualitative analysis of liquids
that dissolve in solvent and nonvolatile
substances (uses liquid cells)
Chapter 4-1Types of Transmission Techniques
FTIR seminar
Types of Transmission Technique
Transmission Techniques
8/13/2019 FT IR Grundl. Seminar
38/89
What You Need
Chapter 4-2KBr Pellet Technique
FTIR seminar
Disk press
Disk diameter 10 mm 5 mm 3 mm 2 mm
Sample amount 500 g 100gSeveral 10's
of gSeveral g
KBr amount 150 mg 20 mg 10 to 7 mg 5 to 3 mg
Pressure 7 t 1 t Hand press Hand press
Microdisk press
3mm- KBr crystals (for IR)- Microdisk press
- Hand press
- Disk holder
Protuberance
is different!
KBr Pellet Technique
Transmission Techniques
FTIR i
8/13/2019 FT IR Grundl. Seminar
39/89
Chapter 4-3How to make disks
FTIR seminar
Short
protuberance
Apply pressure withhand pressPlace in holder
and measure
Insert powder
How to make disks
Transmission Techniques
FTIR seminar
8/13/2019 FT IR Grundl. Seminar
40/89
Chapter 4-4
Thin-film Technique
FTIR seminar
Window
Add drops of solvent
to dissolve sample
Spread out thinly
using a spatula or
similar implement
Measure once the
solvent evaporates
Sample
Thin-film Technique
Transmission Techniques
Ch 4 FTIR seminar
8/13/2019 FT IR Grundl. Seminar
41/89
Chapter 4-5Liquid-film Technique
FTIR seminar
Sandwich the sample between two windows
Place and measure the assembly cell
What You Need- Windows
- Assembly cell
- (Spacer)
- Silicone cloth
Screw
Rubber backing
Cell frame
Windows
Sample
Assembly cell
Spacer (Al or Pb)
Rubber
backingCell frame
Windows
Sample
Spacer
Liquid-film Technique
Transmission Techniques
Ch t 4 6 FTIR seminar
8/13/2019 FT IR Grundl. Seminar
42/89
Chapter 4-6Solution Technique
FTIR seminar
What You Need- Fixed cell for liquid
- SolventChloroform
Carbon tetrachlorideCarbon dioxide
Dissolve the sample in an appropriate
infrared solvent, place it in a fixedliquid cell , and then measure.
Stopper
Stopper
Sample outlet
Spacer
Sample inlet
Metal frames
Window
Solution Technique
Transmission Techniques
Chapter 4 7 FTIR seminar
8/13/2019 FT IR Grundl. Seminar
43/89
Chapter 4-7How to Determine Cell Thickness
FTIR seminar
Measure the empty cell to find the interference curve.
How to Determine Cell Thickness
Transmission Techniques
Chapter 4 8 FTIR seminar
8/13/2019 FT IR Grundl. Seminar
44/89
Chapter 4-8Materials That Transmit Infrared
FTIR seminar
Materials That Transmit Infrared
Applicable
Range(cm-1)Material
KBr
CaF2
KRS-5
ZnSe
Ge
Refractivity
(Approx.)
1.5
1.4
2.4
2.4
4.0
730
1360
414
1100
936
43500 to 400
77000 to 1100
20000 to 250
10000 to 500
5500 to 500
Water-Solubility
(g/100g Water)
53.5
0.0017
0.05
Insoluble
Insoluble
Notes
No mechanical strength
Easily broken
Dissolved in an ammoniasalt solution
Affected by acidic solutions
Soft and easily damaged
Easily broken
Easily broken
Dissolves in warm sulfuric acid
Dissolves in HNO3
(For ATR:up to about 650)
(For ATR:
up to about 700)
Melting Point
(oC)
Materials That Transmit Infrared (1)
Transmission Techniques
Chapter 4-9 FTIR seminar
8/13/2019 FT IR Grundl. Seminar
45/89
Chapter 4 9Materials That Transmit Infrared
Materials That Transmit Infrared
-10
100
0
50
6000 40020004000
%T
Wavenumber[cm- 1]
KBrCaF2 KRS-5
Ge
ZnSe
Materials That Transmit Infrared (2)
Transmission Techniques
8/13/2019 FT IR Grundl. Seminar
46/89
JASCO FTIR Seminar Chapter 5Reflection Techniques
JASCO FTIR Seminar Chapter 4Transmission Techniques
Reflection Techniques
FTIR Seminar
Chapter 5
Chapter 5-1 FTIR seminar
R fl ti T h i
8/13/2019 FT IR Grundl. Seminar
47/89
Types of Reflection Techniques
Solid samples
Liquid samples
ATR technique
Elastic and viscous substances that are
insoluble, infusible, and difficult to grind
up Information of sample surface
Diffuse
reflectance
technique
Substances in powder form or that
can be turned into powder
Those with surfaces that are rough.
Specular
reflection
technique
Film on a metal substrate
(around 0.1 to 5 m)
Solids with a smooth surface
ATR technique Measurement of aqueous solutions
Diffuse
reflectance
technique
Measurement of aqueous solutions
(eliminate water)
RAS techniqueThin film on a metal substrate
(around 10 angstrom to 1 m)
Types of Reflection Technique
Reflection Techniques
Chapter 5-2 FTIR seminarR fl ti T h i
8/13/2019 FT IR Grundl. Seminar
48/89
ATR Technique
Incidentlight
Sample
Prism
Reflected
light
ATR Technique
Reflection Techniques
Chapter 5-3 FTIR seminarReflection Techniques
8/13/2019 FT IR Grundl. Seminar
49/89
Depth of Light Penetration into Sample
Depth of Light Penetration into Sample
Depth of light penetration into sample is determined by:
1. Wavelength (m)2. Incident angle ()
3. Refractivity of prism (n1) and sample (n2)
dp : depth of penetration
dp = [sin2- (n2
/n1
)]-1/2
2222
nnnn1111
Proportional to wavelength
Inversely proportional to prism refractivity
Depth of Light Penetration into Sample
Reflection Techniques
Chapter 5-4T f ATR P i
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
50/89
Types of ATR Prisms
KRS-5
ZnSe
Ge
n1Measurement Target
n2
: incident angle
n1: prism refractivity
n2:sample refractivity
(upper limit of sample refractivity for producing total reflection)
up to 250
up to 625
up to 700
2.4
2.4
4.0
2.1
2.1
3.5
General organic materials
General organic materials
and aqueous solutions
Rubber containing carbon
and extremely thin surfaces
1.7
1.7
2.8
=45o
Measurable
Wavelength
Range =60o
sin n2n1=
>>>>
Types of ATR Prisms
Reflection Techniques
Chapter 5-5Relationship between wavelength and incident angle
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
51/89
Relationship between wavelength and incident angle
Relationship between Wavelength and Incident Angle to depth of
penetration by prism type
5000
2500
1666
1250
1000
833
714
625
555
500
Dp(m)
Wavelength (m)
0 2 4 6 8 10 12 14 16 18 20
Wavenumber (cm-1)
0.5
1.0
1.5
2.0
2.5
Prism Refractivity
KRS-5 n1=2.4
ZnSe
Ge n1=4.0
Sample refractivity n2 = 1.5
Incident angle = 45o
Relationship between Wavelength and Incident Angle
Reflection Techniques
Chapter 5-6Measurement of Rubber Containing a High Concentration of Carbon
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
52/89
Measurement of Rubber Containing a High Concentration of Carbon
Attachment: ATR-300/H
Prism: Ge
Integrations: 20
Resolution: 4 cm-1Detector: TGS
Normally, the ATR technique is
employed to measure rubber
The material for the prism is selected
based on the amount of carboncontained in the rubber
A Ge prismis used when the carboncontent is high, and when the baseline iscurved it is corrected
Before-baseline correction
After-baseline correction
4000 700
%T
Wavenumber[cm-1]
Measurement of RubberContaining a High Concentration of Carbon
Reflection Techniques
Chapter 5-7ATR Correction
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
53/89
ATR Correction
-0.1
2.2
4000 650
Abs
Wavenumber[cm-1]
Before-correction
After-correction
Attachment: ATR-500/M
Integrations: 30
Resolution: 4 cm-1
ATR Correction
Reflection Techniques
Chapter 5-8ATR Technique Features
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
54/89
q
Surface layer information can be measured in a nondestructive manner
No need for sample preparation, and state analysis is possible
By selecting the correct prism, it is possible to adjust the depth of light
penetration into the sample
Using a holder for liquid allows measurement of aqueous solutions aswell
ATR Technique Features
Reflection Techniques
Chapter 5-9Cautions on Usage
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
55/89
g
In most cases, the reason for failing to obtain a good spectrum is a poor bond betweenthe sample and prism. Care must be taken with samples lacking a smooth surface andthose that are hard because a layer of air can easily form between the sample and the
prism during bonding.
Since ZnSe and Ge crystals are fragile, be careful not to apply too much pressure to themor strike or drop them.
Since ZnSe and Ge have absorption in the low wavenumber region, verify the measurablerange.
If a ZnSe prism fails to yield a good spectrum when measuring a material such as rubbercontaining carbon, use a Ge prisminstead.
How to clean a prism:KRS-5 : Rinse the prism with chloroform or similar fluid, being careful not to touch it.ZnSe and Ge :Dampen a Kimwipe or similar wipe product with solvent and lightly wipethe prism.
The KRS-5 should be stored in a desiccator
Cautions on Usage
q
Chapter 5-10Applications
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
56/89
The ATR technique can be applied to measure
the following types of substances:
Elastic and viscous substances that are insoluble, infusible, and difficult to grind up
Rubber, urethane foam, synthetic leather, and thermoset resin
Substances difficult to measure using the thin-film technique
Polymeric thin films
Surfaces consisting of an extremely thin layer that is difficult to measure
Measurement of coatings such as paint, varnish, and lacquer and their change over time
Measurement of adhesive tape and electrical tape surfaces
Identification of coating materials such as paper, metal, cloth, and leather
Measurement of aqueous solutions
Applications
q
Chapter 5-11Diagram of Diffuse Reflectance Principle
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
57/89
Incident angle I
Reflected lightR0
Diffusely reflected lightR1
Diagram of Diffuse Reflectance Principle
Chapter 5-12Kubelka-Munk Equation
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
58/89
Kubelka-Munk Equation
Chapter 5-13Kubelka-Munk
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
59/89
Intensity
Reflectivity
ABSK/M
Qualitative analysis: ABS: 2 or less
K/M: 10 or less
Quantitative analysis: ABS: 1 or less
K/M3 or less
5
4
3
2
1
0
0 10 20 30 40 50 60 70 80 90 100
Kubelka-Munk
Chapter 5-14Spectra of Trehalose
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
60/89
0
100
20
40
60
80
4000 4002000 1000
%%%%RRRR
WWWWaaaavvvveeeennnnuuuummmmbbbbeeeerrrr[[[[ccccmmmm---- 1111]]]]
DR meDR meDR meDR method athod athod athod after dfter dfter dfter dilutionilutionilutionilution
KBrKBrKBrKBrpellpellpellpellet meet meet meet methodthodthodthod
DR meDR meDR meDR method withod withod withod without dithout dithout dithout dilutionlutionlutionlution
Spectra of Trehalose
Chapter 5-15Spectra of Trehalose
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
61/89
0
0.4
0.1
0.2
0.3
4000 4002000 1000
K/M
Wavenumber[cm-1]
After dilution
Without dilution
Spectra of Trehalose
Chapter 5-16Features
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
62/89
(1) Can be used on powder samplesand samples with rough
surfaces
(2) Obtains a spectrum resembling a transmission spectrum but
with a slight difference inthe intensity ratio
=> Weak absorption in the transmission spectrum is enhanced by
the DR spectrum
(3) Compared to the KBr technique, the sampling operation is
easier
(4) Quantitative analysis is also possible by switching to the K/M
function(only when the K/M value is 3 or less)
(5) In addition to room temperature, measurement during or after
heating is possible. Attachments are available for that purpose
Features
Chapter 5-17Important Information Concerning the Diffuse Reflectance Technique
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
63/89
(1) Samples should be in the finest powder form possible
(a particle size of 20 m or less is best)
Prevents specular reflection
Increases number of reflections, thereby
enhancing absorption
(2) Dilute samples with KBr
Dramatically lowers specular reflection
Enables the dilution ratio to be obtain
corresponding to the measurement target
(normally, around several percent)
(3) When focusing on OH groups, use CaF2 powder
instead of the highly hygroscopic KBr powder
Important InformationConcerning the Diffuse Reflectance Technique
Chapter 5-18Applications
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
64/89
Substances that can be measured using the normal KBr technique
Substances difficult to measure using the KBr technique (includes
clay, cement, minerals, and pigment)
Research on adsorption/desorption reactions on catalyst surfaces
Applications
Chapter 5-19Principles of the Specular Reflection Technique
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
65/89
Principles of the Specular Reflection Technique
Medium (air)
I0 I1 I2
I
R
d
n1
n2
n3
Thin film
Metal
I0
I
n1
n2
Chapter 5-20Kramers-Kronig Transform
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
66/89
2.0
7.0
4000 400
%T
Wavenumber[cm-1]
0.0
0.2
4000 400
k
Wavenumber[cm-1]
Pre-conversion
Post-conversion
K/K Transform
By transforming the surface of a
resin or plastic into a specular
surface, it is possible to capture faint
reflected light and obtain the
reflection spectrum.
The reflection spectrum is affected
by the sample s refractivity (n),causing its waveform to change.
This example if for software that
converts the reflection spectrum into
an absorption spectrum.
Kramers-Kronig Transform
Chapter 5-21Kramers-Kronig Transform
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
67/89
-0.8
1.6
0
1
4000 4002000 1000
k
Wavenumber[cm-1]
ReflectionSpectrum
KK Transform
Kramers-Kronig Transform
Chapter 5-22Features
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
68/89
(1) Can obtain spectra simply by placing a sample with a smooth
surface. However, the K/K transformis required to contrast with the
normal transmission spectrum.
(2) Enables state analysis of thin film (approximately 5 m or less)on
a metal substrate.
Features
Chapter 5-23Specular reflectance method
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
69/89
0
1.6
0.5
1
1.5
4000 4002000 1000
Abs
Wavenumber[cm-1]
Specular
reflectance method
Cut off sample
and KBr method
Specular reflectance method
Chapter 5-24Cautions on Usage
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
70/89
(1) The measurement surface must be either a specular surface or smooth
surface.
(2) The reference sample should be a substance as close as possible to the
sample. When a reference is not available, a mirror can be used instead.
(3) When measuring coating film on a reflective substrate, the film thickness
should be between 0.1 and 5 m.
Cautions on Usage
Chapter 5-25Applications
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
71/89
(1) Analysis of film coatings on metal surfaces, deposits, and oxide films
(2) Analysis of samples that have a smooth surface and are difficult to
measure using the transmission technique
(3) Measurement of epitaxial layer thickness
(4) Measurement of relative reflectivity
Applications
Chapter 5-26Applications
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
72/89
0
0.23
0.1
0.2
4000 4002000 1000
Abs
Wavenumber[cm-1]
Reflectance
spectrum
Transmittance
spectrum
Applications
Chapter 5-27High-Sensitivity Reflection Technique
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
73/89
Standing waves
Electric vector of
incident light
Electric vector of
reflected light
Reflection of linearly polarized lighton a metallic surface: In the case of p polarization
High-Sensitivity Reflection Technique
Chapter 5-28Features
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
74/89
(1) Enables the qualitative and quantitative analysis of thin film of around
several tens of to several mthat has been processed on the surface of a
metal substrate.
(2) Absorption increases as the dipole moment approaches 90 degrees.
(3) Most sssseeeennnnssssiiii tttt iiiivvvveeeemethod for measuring thin-films on the surface of metal
substrates.
Features
Chapter 5-29Cautions on Usage
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
75/89
(1) The transmission spectra and patterns of RAS spectra differdepending on the surfaceselection ratio.
(2) This technique should be applied to thin films on the surface of smooth metal substrates.
(3) Notes on handing samples:
Handle samples with tweezers (avoid putting fingerprints on samples).Do not expose the samples to the open air except when measuring
(avoid contamination by airborne debris).
(4) Make sure no absorption exists that will interfere with the reference (unprocessed metal
substrate).
Cautions on Usage
Chapter 5-30Applications
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
76/89
(1) Analysis of surface processing and adsorption of metal substrates and
semiconductor substrates
(2) Residue check after washing metal substrates and semiconductor substrates
(3) Measurement of LB films
(4) Qualitative analysis of compact disc surface lubricating oil
Applications
Chapter 5-31Applications
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
77/89
-0.05
0.40
0.00
0.10
0.20
0.30
4000 4002000 1000
Abs
Wavenumber[cm-1]
RAS
RF
Applications
Chapter 5-32Applications
FTIR seminar
Reflection Techniques
8/13/2019 FT IR Grundl. Seminar
78/89
4000 4002000 1000
Abs
Wavenumber[cm-1]
RAS
Abs=0.31
RF
Abs=0.001
Applications
FTIR seminar
8/13/2019 FT IR Grundl. Seminar
79/89
JASCO FTIR Seminar Chapter 6Quantitative Analysis
Quantitative Analysis
FTIR Seminar
Chapter 6
FTIR seminarChapter 6-1Quantitative Handling of Infrared SpectraQuantitative Analysis
8/13/2019 FT IR Grundl. Seminar
80/89
Absorbance : ABS=log(1/T)
=log( I0 /I)
=x d x c
Ordinate axis is proportional to concentration (c)
: Molar extinction coefficient
d : Depth
c : Concentration
I
Transmissivity measurement
I
100100100100
0
%%%%TTTT
Absorbance
0000
measurement
0000
ABS
Transmissivity : %T=(I/I0) x 100
d
Sample
De
tector
L
ight
source
Interferometer
I0 I
Quantitative Handling of Infrared Spectra
FTIR seminarChapter 6-2Application of Quantitative AnalysisQuantitative Analysis
8/13/2019 FT IR Grundl. Seminar
81/89
PA1
PS1
P
A2
PS2
Key band of acrylonitrile2240cm-1: C N Key band of styrene1,602 cm-1
Benzene rings C=C [Sample 1 ]
[Sample 2 ]
Example: Comparison of component ratios in ABS resin
(acrylonitrile/butadiene/styrene)
Application of Quantitative Analysis
JASCO FTIR Seminar Chapter
FTIR seminar
8/13/2019 FT IR Grundl. Seminar
82/89
7Infrared Spectrum Analysis
Techniques
Infrared Spectrum Analysis Techniques
FTIR Seminar
Chapter 7
FTIR seminar
FTIR seminarChapter 7-1Infrared Spectrum Analysis TechniquesInfrared Spectrum Analysis Techniques
8/13/2019 FT IR Grundl. Seminar
83/89
Overview
Substructure analysis: Analysis of functional groups
Spectrum searching: Identification of compounds
Conditions for obtaining spectra suited to analysis
Select a measurement technique which fits the analysis purpose
Optimum concentration: Low
Decrease the number of components as much as possible during preprocessing
Infrared Spectrum Analysis Techniques
FTIR seminar
FTIR seminarChapter 7-2Substructure AnalysisInfrared Spectrum Analysis Techniques
8/13/2019 FT IR Grundl. Seminar
84/89
(1) Utilize reference material
(2) IR Mentor(application that assists the analysis of infrared spectra)Finds the functional groups for each absorption band
Finds the functional groups for specified peaks
Finds function groups by compound type
The functional groups that have been entered are limited
Substructure Analysis
FTIR seminar
FTIR seminarChapter 7-3Analysis ExampleInfrared Spectrum Analysis Techniques
8/13/2019 FT IR Grundl. Seminar
85/89
Search example (1) : Searching by peak
Analysis Example
FTIR seminar
FTIR seminarChapter 7-4Analysis Example 2Infrared Spectrum Analysis Techniques
8/13/2019 FT IR Grundl. Seminar
86/89
Search example (2): Search by compound classification
Analysis Example 2
FTIR seminar
FTIR seminarChapter 7-5Spectral Search
S t l S h
Infrared Spectrum Analysis Techniques
8/13/2019 FT IR Grundl. Seminar
87/89
Spectral Search(1) Compare with standard spectrum collections
(2) Compare with Sadtler databases
Important Information on Searching
Use a search algorithmsuited to your purpose
Identify whether the sample is made up of single or multiple components
Judge search results by eye based on their resemblance to a pattern rather than emphasizingevaluation points
(Algorithms can quickly find similar spectra in a large volume of data, but they cannot interpret the
spectra they find)
When there are mixtures, the key is to skillfully utilize difference spectra
Obtain other component information in advance whenever possible
Spectral Search
FTIR seminar
FTIR seminarChapter 7-6
Spectral Search Example
S t l S h E l
Infrared Spectrum Analysis Techniques
8/13/2019 FT IR Grundl. Seminar
88/89
Spectral Search Example
FTIR seminar
FTIR seminarChapter 7-7Spectral Search Example (Difference Spectrum)
Spectral Search E ample (Difference Spectr m)
Infrared Spectrum Analysis Techniques
8/13/2019 FT IR Grundl. Seminar
89/89
Spectral Search Example (Difference Spectrum)