ft ir grundl. seminar

8/13/2019 FT IR Grundl. Seminar

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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


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JASCO FTIR Seminar Chapter 1Principles and Fundamentals of Infrared Spectroscopy

Principles and Fundamentalsof Infrared Spectroscopy

FTIR SeminarChapter 1


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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


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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


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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


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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



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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



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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)



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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)



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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



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FTIR seminarChapter 1-8Molecular Vibration of Polyatomic Molecules

Example : Acetaldehyde

Molecular Vibration of Polyatomic Molecules



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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



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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


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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



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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



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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



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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



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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



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JASCO FTIR Seminar Chapter 2Principles of FTIR

Principles of FTIR



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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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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JASCO FTIR Seminar Chapter 3Standard Data Processing Features

Standard Data Processing Features



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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




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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



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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



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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



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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



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JASCO FTIR Seminar Chapter 4Transmission Techniques

Transmission Techniques

FTIR Seminar

Chapter 4


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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



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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


FTIR i


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Chapter 4-3How to make disks

FTIR seminar

Short

protuberance

Apply pressure withhand pressPlace in holder

and measure

Insert powder

How to make disks


FTIR seminar


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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


Ch 4 FTIR seminar


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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


Ch t 4 6 FTIR seminar


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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


Chapter 4 7 FTIR seminar


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Chapter 4-7How to Determine Cell Thickness

FTIR seminar

Measure the empty cell to find the interference curve.

How to Determine Cell Thickness


Chapter 4 8 FTIR seminar


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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)


Chapter 4-9 FTIR seminar


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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)



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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


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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


Chapter 5-2 FTIR seminarR fl ti T h i


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ATR Technique

Incidentlight

Sample

Prism

Reflected

light

ATR Technique


Chapter 5-3 FTIR seminarReflection Techniques


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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



Chapter 5-4T f ATR P i

FTIR seminar



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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


Chapter 5-5Relationship between wavelength and incident angle

FTIR seminar



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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


Chapter 5-6Measurement of Rubber Containing a High Concentration of Carbon

FTIR seminar



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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


Chapter 5-7ATR Correction

FTIR seminar



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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


Chapter 5-8ATR Technique Features

FTIR seminar



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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


Chapter 5-9Cautions on Usage

FTIR seminar



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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



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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



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Incident angle I

Reflected lightR0

Diffusely reflected lightR1

Diagram of Diffuse Reflectance Principle

Chapter 5-12Kubelka-Munk Equation

FTIR seminar



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Kubelka-Munk Equation

Chapter 5-13Kubelka-Munk

FTIR seminar



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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



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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



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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



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(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



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(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


FTIR seminar



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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



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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



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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

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-0.8

1.6

0

1

4000 4002000 1000

k

Wavenumber[cm-1]

ReflectionSpectrum

KK Transform

Kramers-Kronig Transform


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(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

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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


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(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


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(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


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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

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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


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(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


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(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


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(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


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-0.05

0.40

0.00

0.10

0.20

0.30

4000 4002000 1000

Abs

Wavenumber[cm-1]

RAS

RF

Applications


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4000 4002000 1000

Abs

Wavenumber[cm-1]

RAS

Abs=0.31

RF

Abs=0.001

Applications

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JASCO FTIR Seminar Chapter 6Quantitative Analysis

Quantitative Analysis

FTIR Seminar

Chapter 6

FTIR seminarChapter 6-1Quantitative Handling of Infrared SpectraQuantitative Analysis


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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


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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

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7Infrared Spectrum Analysis

Techniques

Infrared Spectrum Analysis Techniques

FTIR Seminar

Chapter 7

FTIR seminar

FTIR seminarChapter 7-1Infrared Spectrum Analysis TechniquesInfrared Spectrum Analysis Techniques


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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


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FTIR seminarChapter 7-2Substructure AnalysisInfrared Spectrum Analysis Techniques


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(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


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Search example (1) : Searching by peak

Analysis Example

FTIR seminar

FTIR seminarChapter 7-4Analysis Example 2Infrared Spectrum Analysis Techniques


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Search example (2): Search by compound classification

Analysis Example 2

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FTIR seminarChapter 7-5Spectral Search

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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

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FTIR seminarChapter 7-6

Spectral Search Example

S t l S h E l



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Spectral Search Example

FTIR seminar

FTIR seminarChapter 7-7Spectral Search Example (Difference Spectrum)

Spectral Search E ample (Difference Spectr m)



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Spectral Search Example (Difference Spectrum)

ft ir grundl. seminar

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