výběr z aplikací infračervené
TRANSCRIPT
The Leader in Spectroscopy
Výběr z aplikací infračervené spektrometrie
Ján Pásztor, Nicolet CZ s.r.o.
The Leader in Spectroscopy
Fourier Transform Infrared Spectroscopy
• IntroductionElectromagnetic radiation
Vibrational spectroscopy
• Instrumentation Interferometry
The Fourier Transform
The Leader in Spectroscopy
10 10 10 10 10 10 10 109 7 5 3 1 -1 -3 -5
Wavenumbers
x-rays
ultraviolet
visible
near-IR
mid -IR
far-IR
microwave
radio waves
Wavelength in microns
nuclear electronic vibrational
10 10 10 10 10 10 10 10
transitions
-5 -3 -1 1 3 5 7 9
rotational
Electromagnetic Spectrum
The Leader in Spectroscopy
Harmonic Vibrations
• The vibration of a diatomic molecule can be approximated by the vibration of a spring
• The wavenumber of the vibration equals:
with m=
1
2x
c
k
m1m2
m1 + m2
m
RRee--DDRR RRee RRee++DDRR
The Leader in Spectroscopy
Quantized harmonic, anharmonic
hh/2/2pp ((k/k/M).(M).(νν+1/2)+1/2)
The Leader in Spectroscopy
Selection Rules for Infrared Activity
• The frequency of the light must be identical to the frequency of the vibration (resonance)
• The dipole of the molecule must change during the vibration
• The direction of the dipole change must be the same as the direction of the electric field vector
The Leader in Spectroscopy
Cl H N N
Dipole Change
• To absorb energy, the dipole must change when the transition occurs
• The intensity of the absorption is proportional to the magnitude of the dipole change
The Leader in Spectroscopy
C CC C
Stretching Deformation
Bending Twisting
C
+ -
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
%T
1000 1500 2000 2500 3000 3500 4000
cm-1
Molecular Vibrations
The Leader in Spectroscopy
1000 1500 2000 2500 3000 3500
Wavenumbers (cm-1)
Fingerprint region
Functional groups
Polyatomic Molecules
• The spectrum becomes more complex as the number of bonds increases
The Leader in Spectroscopy
Non-linear Triatomic Molecule (H2O)
• 3 normal vibrations (3N-6)
• Coupling of vibrations bendingbending
(1595 cm(1595 cm--11))
symmetricsymmetric
stretchingstretching
(3657 cm(3657 cm--11))
asymmetricasymmetric
stretchingstretching
(3756 cm(3756 cm--11))
E1
E2
E E
En
erg
y
Fre
qu
en
cy
The Leader in Spectroscopy
Fixed Rotations in a Lattice (-CH2)
scissoringscissoring
(~1463 cm(~1463 cm--11))
twistingtwisting
(~1300 cm(~1300 cm--11))
waggingwagging
(~1280 cm(~1280 cm--11))
+ +
+-
CHCH22 rocking at 720 cmrocking at 720 cm--11
• Since the atoms are fixed in a skeleton, more bending vibrations occur
The Leader in Spectroscopy
Overtones
Occur close to INTEGER
MULTIPLES Of FUNDAMENTAL Bands.
For example: C-H Overtones Will Occur Near:
First Overtone
2960 cm-1 (C-H Stretch) * 2 = 5920 cm-1
Second Overtone
2960 cm-1 (C-H Stretch) * 3 = 8880 cm-1
The intensity of the absorption depends on the degree of
anharmonicity and gets weaker with increasing overtones
The Leader in Spectroscopy
Combination Bands
COMBINATION Bands Appear Near The Sum Of
Two Or Three FUNDAMENTAL Bands
For Example: A C-H Combination Will Occur Near…
2960 cm-1 (C-H Stretch) + 1460 cm-1 (C-H Bend)
= 4420 cm-1
The Leader in Spectroscopy
NIR spectrum
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
700 900 1100 1300 1500 1700 1900 2100 2300 2500
Wavelength (nm)
Ab
so
rban
ce (
Lo
g 1
/R)
Combination
1st Overtone
2nd Overtone
3rd Overtone
The Leader in Spectroscopy
Sources, Beamsplitters and Detectors
The Leader in Spectroscopy
Source, Beamsplitter, and Detector Combinations Depend on Application
The Leader in Spectroscopy
FT-IR System
The Leader in Spectroscopy
+ =
+ =
Wave Interactions (Interference)
• In-phase Constructive
interference
• Out-of-phase Destructive
interference
The Leader in Spectroscopy
DetectorDetector
Michelson Interferometer-1
Fixed mirrorFixed mirror
l 0 -l
InterferometerInterferometer
Moving mirrorMoving mirror
IR IR
SourceSource
BeamsplitterBeamsplitterBM
Path difference = 0
BMBF =
BF
The Leader in Spectroscopy
Michelson Interferometer-2
Detector
Fixed mirrorFixed mirrorInterferometerInterferometer
Moving mirrorMoving mirror
l 0 -l
IR IR
SourceSource
BeamsplitterBeamsplitterBM
Path difference = 1/4
BM - 1/8 BF =
BF
DetectorDetector
The Leader in Spectroscopy
Michelson Interferometer-3
Fixed mirrorFixed mirror
DetectorDetector
InterferometerInterferometer
Moving mirrorMoving mirror
l 0 -l
IR IR
SourceSource
BeamsplitterBeamsplitter
Path difference = 1/2
BM - 1/4 BF =
BM
BF
The Leader in Spectroscopy
Fixed mirrorFixed mirror
BeamsplitterBeamsplitter 0 0 --
DetectorDetector
InterferometerInterferometer
IR IR
SourceSource
Michelson Interferometer-4
Moving mirrorMoving mirror
The Leader in Spectroscopy
Path difference
Signal at the Detector
Vo
lta
ge
0 1/4 1/2 3/4
The Leader in Spectroscopy
The Interferogram
One Wavelength Many Wavelengths
020406080100120140
-1.0
-0.5
0.0
0.5
1.0
010002000300040005000
-3
-2
-1
0
1
2
3
4
Data Points Data Points
Vo
lts
Vo
lts
The Leader in Spectroscopy
Sampling the Interferogram
Source
He-Ne laser
The Leader in Spectroscopy
Dynamic Alignment
Fixed mirror
x 0 -x
Beamsplitter
Laser diodes
He-Ne laserMoving mirror
XYR
The Leader in Spectroscopy
Dynamic Alignment Advantages
• Better short term stability
• Better long term stability
• Better spectral line shapes
The Leader in Spectroscopy
5001000150020002500300035004000
5
10
15
20
25
30
35
40
Wavenumbers
Fast Fourier Transformation
FFT
010002000300040005000
-3
-2
-1
0
1
2
3
4
Data Points
V
o
l
t
s
Interferogram Spectrum
E
m
i
s
s
i
v
i
t
y
The Leader in Spectroscopy
Transmission Spectrum
170018001900210022002300
-3
-2
-1
0
1
2
3
4
Data Points
Vo
lts
170018001900210022002300
-3
-2
-1
0
1
2
3
4
Data Points
Vo
lts
5001000150020002500300035004000
5
10
15
20
25
30
35
40
Wavenumbers
Em
issiv
ity
5001000150020002500300035004000
5
10
15
20
25
30
35
40
WavenumbersE
mis
siv
ity
bkg: FFT
sam: FFT
5001000150020002500300035004000
20
30
40
50
60
70
80
90
Wavenumbers
Tra
nsm
itta
nce
Ratio
The Leader in Spectroscopy
Summary
Advantages of FT-IR Instruments
• Multiplex advantage (Felgett’s) All wavelengths are measured simultaneously
• Throughput advantage (Jacquinot’s) Higher energy throughput (larger apertures)
• Precision advantage (Connes’) Internal calibration is derived from He-Ne laser (precision = 0.01 cm-1)
The Leader in Spectroscopy
Technique Choice
• Analytical goals Quantitative
Qualitative
• Sample dependent factors Size
Chemical makeup of sample
• Optimization
The Leader in Spectroscopy
Sampling Techniques and Applications
• Transmission
• Attenuated Total Reflectance - ATR
• Diffuse Reflectance – DRIFTS
• Gas Analysis
• Semiconductor
• Oil Analysis
• GC/FT-IR
• TGA/FT-IR
• Mobile/Portable FT-IR
The Leader in Spectroscopy
Advances in Accessory Design
• Automatic set-up of system parameters and experiment
• Rugged, permanently aligned, plug & play design
• On-line help and tutorials
• Design for fast purge
• Operation integrated with spectrometer and software
• Automatic tests ensure proper accessory operation
• System checks ensure high quality spectra are collected
The Leader in Spectroscopy
Transmission Analysis
• Requires sample preparation
• Proper pathlength required Strong absorbers - short pathlength
Weak absorbers - long pathlength
• Solids, liquids, gases
• Qualitative analysis
• Quantitative analysis
• Maximum sensitivity
• Low cost
The Leader in Spectroscopy
The peak at 3651 cm-1
was used to quantify the
antioxidant butylated hydroxy
toluene (BHT) in the poly-a-olefin
(PAO) lubricant
Analysis of Antioxidant Levels in Lubricating Oil
The Leader in Spectroscopy
Attenuated Total Reflectance
• Versatile and non-destructive technique for infrared sampling
• Requires minimal or no sample preparation
• Useful for surface characterization
The Leader in Spectroscopy
Considerations for ATR Analysis
• Refractive index of ATR and sample
• Pathlength requirements
• Spectral range of interest
• Phase of sample: solid, liquid, gel
• Chemical properties
• Hardness of sample
d p =
2p natr (sin2 q) -nsample
natr( )2[ ] 1/2
The Leader in Spectroscopy
Attenuated Total Reflectance ATRSingle Bounce vs Multi-bounce
• Small sampling area
• Use for strong absorbers
• Solid samples
• Broad sampling area provides
greater contact with the sample
• Use for weak absorbers or dilute
solutions
ZnSe Internal Reflection Element
Penetration depth
up to two micronsPlunger
Crystal Cap
IR Beam
Crystal
The Leader in Spectroscopy
Properties of ATR Crystals
Material
ATR Spectral
Range (cm-1)
Refractive
Index
Depth of Penetration (µ)
(at 45º & 1000 cm-1) Uses
Germanium 5,500 - 675 4 0.66
Good for most samples.
Strong absorbing
samples, such as dark
polymers.
Silicon8,900 - 1,500 &
360-1203.4 0.85
Resistant to basic
solutions.
AMTIR 11,000 - 725 2.5 1.77Very resistant to acidic
solutions.
ZnSe 15,000 - 650 2.4 2.01 General use.
Diamond 30,000 - 200 2.4 2.01
Good for most samples.
Extremely caustic or hard
samples.
The Leader in Spectroscopy
Analysis of Fibers Using Single Bounce ATR
• No sample preparation
• Non-destructiveto the sample
• Shallow depthof penetrationgood for dark polymers
The Leader in Spectroscopy
Identifying Fiber Threads Inside An Automotive Hose
The Leader in Spectroscopy
ATR Summary
• Ease-of-use
• Rapid qualitative and quantitative analysis
• No sample preparation
• Multiple crystals for various sampling needs
• Best technique for condensed phase samples
The Leader in Spectroscopy
Diffuse Reflectance (DRIFTS)
• A multi-modal technique Specular Reflectance
Diffuse Specular Reflectance
“True” Diffuse Reflectance
• Kubelka-Munk equation Absorbance-like results
R = reflectance with infinite depth
K = molar absorption
S = scattering coefficient
F(R) = (1-R)2
2R =
KS
The Leader in Spectroscopy
Compound Parabolic Concentrator
• Independent of sample height
• Reduces sample packing effects
• Minimizes front surface reflection (specular component)
• Efficient high throughput collection optics
• Sample positioned below optics
• No damage to optics from sample spills
Input / output optics
CPC
Powder sample cup
CPC Design
The Leader in Spectroscopy
DRIFTS Analysis of Pharmaceutical Powders
The Leader in Spectroscopy
DRIFTS Analysis of Pharmaceutical Powders
Analytical Goal
• Simplified sample preparation
• Identification of key ingredients
Ibup ro fen Powder
0.3
0.4
0.5
Lo
g(1
/R)
Nap roxen Sodium Powder
0.2
0.4
0.6
Lo
g(1
/R)
Ps eudoephedrine H Cl Powder
0.50
0.55
0.60
0.65
0.70
0.75
Lo
g(1
/R)
600 800 1000 1200 1400 1600 1800
Wav enumbers (cm-1)
The Leader in Spectroscopy
Benefits of Diffuse Reflectance
• Good choice for dilute powders
• Analysis of non-reflective materials
• Minimal sample preparation
The Leader in Spectroscopy
FT-IR Gas Analyzer
• Detects pollutants CO, NOx, HC
NH3, HCN, N2O
• Nexus Gas Analyzer 2 meter gas cell
MCT-A detector
• Detection limits – less than 1 ppm
• 0.09 cm-1 resolution
The Leader in Spectroscopy
NOx Reduction in Diesel Exhaust
• Diesel engines are run “lean,” i.e. with excess air during combustion
• “Naturally” low hydrocarbon and CO emissions but high NO and NO2
emissions
• “Urea” with catalyst can reduce NO and NO2
• However, concern is that HCN is generated
The Leader in Spectroscopy
HCN Emissions
• “Urea” injection reduced NO and NO2 and can be tuned to minimize HCN generation
Abs
HCN 97 ppm in exhaustHCN 0.6 ppm in exhaustHCN standard
-0.2
-0.0
0.2
0.4
0.6
0.8
1.0
3250 33003350cm-1
The Leader in Spectroscopy
Semiconductor Wafer Analysis
• Semiconductor devices are manufactured on silicon wafers, using successive layers of metals and insulators
• Many devices are produced from each wafer. As many as 300 PentiumTM like devices, or more than 800 memory chips, can be produced from a single 8” or 12” diameter wafer
The Leader in Spectroscopy
Semiconductor Analysis
• The samples were analyzed using the Nicolet® ECO 3000
• Samples were scanned in transmission (silicon is transparent to infrared radiation)
The Leader in Spectroscopy
Si-H Variation
The Leader in Spectroscopy
Conclusion
• Hydrogen concentration can effect the dielectric constant in these films
• Customer was able to identify a heating problem with the wafer platen in the deposition system, based on the shape of the center region of the profile
• After adjusting the temperature parameters in the system, uniform films were produced and device yields reached 98%
The Leader in Spectroscopy
Approaches for Lubricant QCTotal Process Checking
• Incoming ingredient testing Base oil and add-pack lot consistency
• Blended product analysis Additive levels
• Outgoing product verification Assure product correct for shipment
• Used Oil Analysis Engine Monitoring
• Edible Oil Analysis Product Consistency
The Leader in Spectroscopy
Integra Oil Analysis
The Leader in Spectroscopy
Spectral Regions of Interest for Used Oil
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Absorbance
1000 1500 2000 2000 3000 4000
Wavenumber
Water
CarboxylCarboxyl
Soot
NitroSulfate
Glycol
Fuel
Phosphate
Anti-wear
The Leader in Spectroscopy
Polymer Additive Identification by GC/FT-IR
• Reverse Engineering Customer wants to deformulate competitive product
Product is complex polymer with several additives
GC analysis alone was inconclusive
• Infrared spectroscopy was necessary for identification of additives
The Leader in Spectroscopy
Nicolet® Nexus® GC/FT-IR System
The Leader in Spectroscopy
Polymer Additives by GC/FT-IR
Real-Time Display
8 cm-1 Resolution
0.74 sec/spectrum
The Leader in Spectroscopy
GC/FT-IR Peak Identification
The Leader in Spectroscopy
TGA/FT-IR Rubber Gasket Characterization
•High pressure and temperature application
•Gasket from backup supplier fails
•TGA only reveals small difference
•TGA/IR reveals compositional differences
The Leader in Spectroscopy
TGA/FT-IR System
• TGA
• FT-IR spectrometer
• TGA/IR interface
• OMNIC Series software
The Leader in Spectroscopy
TGA/IR Data of Rubber Gaskets
• 8 cm-1 resolution
• DTGS detector
• 10.0 sec time resolution
• OMNIC Series software
The Leader in Spectroscopy
TGA/IR Spectra of Rubber Gasket Samples
The Leader in Spectroscopy
Library Search Results
The Leader in Spectroscopy
Mobile and Portable Infrared Analysis
• Incident Preparedness and Response (IPAR)
•First Responders
•Fire Fighters
•Clandestine Lab Investigators
•WMD/CST
•US Army/US Navy
The Leader in Spectroscopy
Implementation
• Mobile system offers full sampling flexibility in a small footprint
Expandability and flexibility
AC power necessary
GLP or 21 CFR Part 11 software tools
• Portable system offers rapid setup and simplicity of operation
Compact, integrated, transportable system
Flexible power sources - AC, 12 volt or battery
Laptop computer compatibility via USB
The Leader in Spectroscopy
Mobile Solution
Dynamic Interferometer alignment
Rugged--Sealed and desiccated or Purgeable
Smart accessories ease sample preparation
Full OMNIC capability
IR Microscope ready
GLP, Validation
21 CFR Part 11 Compliance tools
Full laboratory capability in a small footprint
The Leader in Spectroscopy
Hazardous Sample Analysis Accessory
• Smart Golden Gate Diamond ATR
• Natural Type IIa diamond
• Diamond brazed to tungsten
carbide disk
• Top plate removable for glove box
loading
• Sample anvil isolates sample from
environment
• Extremely easy-to-use and simple
decontamination
The Leader in Spectroscopy
Hazardous Materials Analysis Mustard HD
-0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0.11
0.12
0.13
0.14
Ab
so
rba
nce
1000 1500 2000 2500 3000 3500
Wav enumbers (cm-1)
The Leader in Spectroscopy
Conclusions - Sampling Techniques
• Thermo Electron FT-IR spectrometers provide a broad range of analytical solutions
• We develop new sampling technologies based upon your sampling needs
• Speed, resolution and sensitivity of our systems can be tuned to your experiment
• Let us know how we can help solve your analytical problems
The Leader in Spectroscopy
Human Hair Analysis
• Verify the fiber to be consistent or inconsistent with hair fromthe suspect
• FT-IR microscope w/ ATR objective
The Leader in Spectroscopy
Surface Analysis of Hair
• ATR, excellent surface analysis tool
• Maximizes surface response
Hair without Hairspray
Hairspray on Hair
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
Ab
sorb
an
ce 1000 2000 3000 4000
Wavenumbers (cm-1)
The Leader in Spectroscopy
Surface Analysis of Hair
• Difference FT-IR bands consistent with PVA hair spray
• ATR microscopy - surface sensitive, non-destructive
Subtraction Result: Hairspray on hair - hair
PVA from Library
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Ab
sorb
an
ce 1000 2000 3000 4000
Wavenumbers (cm-1)
The Leader in Spectroscopy
Fiber from Crime Scene
• Fiber Diameter - 20 microns
• ATR Objective Sample Area - 7 microns
The Leader in Spectroscopy
Micro ATR Fiber Spectrum
20 micron diameter fiber by Micro-ATR
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
A
b
s
o
r
b
a
n
c
e
1000 1500 2000 2500 3000 3500 4000
The Leader in Spectroscopy
Paint Chip Analysis
• Automotive Paint Identification
• Multilayered, 20-25 microns each
• Redundant Aperturing Required
The Leader in Spectroscopy
View-Thru Aperturing - 15x15 microns
Analyze !Both Apertures
Lower ApertureNo Apertures
The Leader in Spectroscopy
Paint Spectra
Grey Layer - 25 microns thick
Red Layer - 17 microns thick
Clear Layer - 25 microns thick
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
A
b
s
o
r
b
a
n
c
e
1000 1500 2000 2500 3000 3500 4000
Wavenumbers (cm-1)
The Leader in Spectroscopy
NIR Spectroscopy
Advantages
• Easier Remote sampling
• No sample preparation
• Glass is “transparent”
• Quick data collection
Disadvantages
• Difficult or impossible to interpret spectra
• More complex to develop methods
• Difficult to add extra compounds to a sample ID method
The Leader in Spectroscopy
SabIR Near-IR Fiber Optic Accessory
The Leader in Spectroscopy
NIR Fiber Optic Sampling
Aspirin Tablet in Packaging
0.5
1.0
Abso
rbance
6000 8000
Wavenumbers (cm-1)
The Leader in Spectroscopy
Polyvinyl Chloride / Vinyl Acetate Copolymers
PVC100
PVC/AC 90/10
PVC/AC 87/13
PVC/AC 81/17
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
Abs
orba
nce
5000 6000 7000 8000 9000 10000
Wavenumbers (cm-1)