Infrared and Raman Imaging at the
Speed of Light
ACS Molecular Spectroscopy Workshop
August 11, 2014
Overview
• Fundamentals of Infrared Microscopy
• Infrared Microscopy and Sampling
• Infrared Chemical Imaging
• Applications
• Summary
Thermo ScientificTM
NicoletTM iNTM10MX
Thermo ScientificTM
NicoletTM Continuum
2
Why Choose Infrared Spectroscopy
• Fast, Flexible, and Specific
• Determine identity and composition
• Qualify and Quantify materials
• Well Developed Tools
• Hardware components rugged and
easy to use
• Analysis software provides
answers
3
Molecular Vibrations Provide Unique Information
Bending
Twisting
+
C
C
C
C
C
Deformation
Stretching
100
90
80
%T
70
60
50
40
30
20
4000
4
3500
3000
2500
2000
Wavenumbers (cm-1)
1500
1000
FT-IR Microscopy
• FT-IR microscopy is a combination of light
microscopy and FT-IR spectroscopy, which
allows the viewing of the sample and its
chemical characterization
5
The Value of FT-IR Microscopy
• Essential technique for…
• Analytical Services and Applied Research Laboratories
• Root cause analysis of defects, inclusions and other types of failure
• Characterization of multi layer structures and materials distribution
• Patent protection and intellectual property
• Forensic and Government Laboratories
• Crime scene trace evidence
• Counterfeiting and customs imported goods inspection
• Identification of trace levels of hazardous material
• Contract Laboratories
• Microanalysis analytical services
• Academic and Research Laboratories
• Structural analysis of minerals, art restoration artifacts, biological samples,
natural and synthetic fibers, wood and paper chemistry, and material
science
6
THE True Value of Infrared Microscopy
• SIMPLE, QUICK and EASY!
• Rapid analyses leads to greater productivity
• Just about anything done with an IR spectrometer can
be done with an IR Microscope
• Economies of scale – Small samples are easier to prepare
• “No WORK is ever done on an IR Microscope”
• FTPPC - ‘Flat, Thin, Parallel, Perpendicular, Clear’
equals Great Spectra!
• “I can always make a LARGE sample SMALLER,
BUT, I can’t make a SMALL sample LARGER!”
Net Result: I’m WAY MORE PRODUCTIVE!
7
The Value of FT-IR Microscopy
Which FT-IR microscopy technique best fits your needs?
• Point and shoot is for…
0.18
0.14
+
Ab s
0.12
• Single specimen identification
0.10
0.08
0.06
0.04
+
0.02
0.00
0.8
N y l on Li bra ry ma tch
0.7
0.6
0.5
Ab s
• Fibers
• Particles
• Inclusions
• Observe, get a spectrum, and identify
R e d Fi be r e mb ed de d i n m on ey
0.16
0.4
0.3
0.2
0.1
0.0
400 0
350 0
300 0
250 0
200 0
150 0
100 0
500
W av enu mber s ( c m- 1)
Polyurethane adhesive
• Mapping is for…
• Sections and small area characterization
• Laminates
• Paint chips and other cross sections
• Small area materials distribution studies
• Observe, get a series of spectra and identify / measure
• Imaging is for…
• Large area characterization
• Observe, set an area, get an array of spectra and
extract chemical information
8
Polyethylene
Polyamide
EVA
EVOH
Polyethylene
Automation for Chemical Maps and Images
• Discrete Sampling
• Autosampling
+
• 1-D Line maps
• Cross-Sections
• 2-D Area maps
• Chemical Images
9
+
+
+
Nicolet Continumm Microscope
• Best spectral purity
•
•
•
•
Dual aperture
Infinity corrected optics
Dual detectors
Four-place nosepiece
• Best spatial resolution
• Better than 5 microns, Slide-On Tip
ATR
• Simultaneous viewing and collection
• Best viewing capabilities
• Infinity corrected, Reflachromat™
• Ideal choice for demanding
applications
• Contrast enhancement options
• Polarized light
• Fluorescence
• Differential Interference Contrast
10
Minimizing Diffraction Effects
• First pass through the aperture between infrared source and sample
limits IR beam to desired sample area (Targeting™)
• Technique used on both the Nicolet iN10 and the Nicolet Continuµm
microscopes
• Second pass through the aperture reduces the amount of diffracted light
reaching the detector (Dual Remote Aperturing)
• Exclusive to the Nicolet Continuµm microscope
90% energy
54% energy
40% energy
11
Reflachromat™ Optics
• Compensation Advantages in Transmission
• Uncompensated (left), Continuum infinity corrected optics provide a
good image, better than other IR microscopes
• Compensated (right), with Reflachromat™ compensation the image is
perfect - the aperture is sharp and clear
Sample
Cassegrain optics
12
Salt windows
Reflachromat™ optics
Contrast Enhancement Techniques
• Infinity corrected optical design
• Improve contrast for samples lacking
features under brightfield illumination
• Applications - polymers, biologicals,
pharmaceuticals, forensics, minerals,
semiconductors, food and beverage
• Polarized light
• Fluorescence
• Differential Interference Contrast (DIC)
Fluorescence
Reveals small sample details
13
Differential interference contrast
Imparts color & 3D effects to isotropic samples
Polarized light
Features due to optical anisotropy
DIC Reveals More Details
• How many layers do you see here?
• How many now?
• The two thin lines in the
center are not just boundaries
• They show different refractive
index hence, they are layers
of a different material
Polymer laminate film
14
Flexible Objective Choices
Dedicated objectives
• 32X Reflachromat™
• ATR objective
• GAO objective
• Visible objectives
 Slide-On ATR Objective
• Transmission, Reflection and ATR
• Variable depth of penetration
• Reflachromat™ compensation
• Infinity corrected, superior viewing
• Easy to use and cost effective
• Easy to clean (ATR) and robust
15
IR Microscope Image Creation
Image Plane
(Aperture)
• Magnified sample image is at
the front of Aperture
• Backside of aperture imaged
on to detector element,
minified.
• When image of aperture is
larger than detector – the
detector becomes the effective
limiting aperture
Image Plane
(Detector Element)
Object Plane
(Sample)
16
• Example:1.5 mm physical
aperture projects down to a 100
micron image on the sample
and to a 250 micron image on
the detector
Chemical Imaging Using Apertures – ‘Pixel’
• Simultaneous collection of data while viewing the
sample
• TruView™ Simultaneous View And Collection
• View a live IR spectrum while adjusting the aperture
• Full view of the sample even when masked
• Separate illumination shows image of off-axis
aperture projected onto sample
Digital Video
Aperture
17
Inclusion Analysis through Visual Imaging
Abs
1.2
Sample = Inclusion in film
1.0
0.8
Abs
1.0
Reference = bulk film
0.5
0.0
Abs
1.0
Polycarbonate resin, ultra high molecular weight
0.5
2000
18
1800
1600
1400
Wavenumbers (cm-1)
1200
1000
Contamination Analysis by ATR
 Surface or embedded particles found in
polymer films during production
 Small defects can cause product failures
• Irregular surface
• Blemishes
• Prevent ink and adhesive applications
19
Slide-On ATR Objective Benefits - Flexibility
 Flexibility of measurements
• From Carbon Black filled materials to thin layers..
• Depth of penetration 0.4 to about 0.8 microns
• Minimum spot size from 25 to <10 microns
• Probe depth* up to 5 mm
 The Slide-On is the only micro ATR Objective
that covers every need!
(*) Probe depth
20
5 mm
Slide-On Tip ATR Benefits, Spatial Resolution
100
10 um PS sphere max apertures - no atmo s supp
%T
95
90
85
80
100
6 um PS sphere max apertures
%T
98
96
94
92
90
%T
100
3 micron PS particle max apertures
99
98
350 0
300 0
250 0
200 0
W av enu mber s ( c m- 1)
21
150 0
100 0
Slide-On ATR Benefits Survey ATR
The Slide-On design
makes it easy to clean
the crystal
22
Polymer Inclusions by Micro ATR
• Analysis of contaminates between polymer
layers by micro ATR analysis
Foam Sheet
Foa m N o In cl u si o n
0.12
0.10
Ab s
0.08
0.06
Slip Agent
0.04
0.02
0.00
0.5
W h ite in cl u si o n G e TIP A TR
0.4
Inclusion
Ab s
0.3
0.2
0.1
0.0
400 0
350 0
300 0
250 0
200 0
W av enu mber s ( c m- 1)
23
150 0
100 0
500
Line Scan Collection - Transmission
• Food packaging laminates and paint chips (cross-sections)
• Transmission measurement, compression cell
• TIP - Draw a line scan perpendicular to sample, set the aperture to fit
the smallest layer and rotate it until parallel to sample
Polyurethane adhesive
Polyethylene
Polyamide
EVA
EVOH
Polyethylene
24
Single Element Mapping for IR Chemical Imaging
25
Nicolet iN10 FT-IR Integrated Microscope
• Stand-alone microscope
• Incorporates all FT-IR critical
components: interferometer, source,
laser and detectors
• Does not require an external
spectrometer
• Microscopy simplified
•
•
•
•
Single Aperture
Fixed focal length
15X Objective
Three detector options
• Unparalleled advantages
•
•
•
•
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High signal to noise performance
Room temperature microscopy
Small footprint, stand alone unit
High performance array detector
Room Temperature Detector for Microscope
• Optimized DTGS room temperature detector
• No liquid nitrogen
• Quick point and shoot analysis
25 micron crystal
transmission
one minute scan
Identified as
Ibuprofen with match
index = 91
27
Preview and Search
28
Tablet Chemical Imaging with Standard MCT-A Detector
Video Image
ca. 17.5 x 7
mm
API #1
Excipient #1
API #2
Excipient #2
Ultrafast Map 221735 spectra
100 x 100 mm Aperture - 25 mm steps (x & y)
0.113 seconds per spectrum - 8 cm-1 data spacing
Reflectance Mode
29
2-D Imaging Hardware Options
• Random Points and 1-D Maps, Speed not a factor
• 2-D Maps can be time intensive
• ultrafast tech in MX pays back
• Factors affecting collection
• area, spatial resolution, spectral resolution, averaging time/pixel, detector
1200 mm
Conventional Mapping
2700 seconds (45 minutes)
Nicolet iN10 MX MCT, single
270 seconds
(4.5 minutes)
Nicolet iN10 MX MCT Array
20 seconds
(0.3 minutes)
16 cm-1, 25 micron pixel, 1 scan/pixel
1200 mm
30
Chemical Imaging: High Resolution and Speed
Video Mosaic
Chemical Images
Skin oil on business card paper
•
•
•
•
•
31
160 spectra per second (10 stage steps per second)
10 x 10 mm = 160.000 spectra
Ultrafast imaging (25 micron spatial resolution, 16 cm-1 spectral res)
Sample collection time: 19 minutes
Total collection time, with background: 23 minutes
2-D Chemical Imaging – Selecting Response Metric
• Transmission mode sampling
• Example of uni-variate response
metric: Intensity at 1645 cm-1 for
polyamide section of polymer film
• Blended IR/Video help to visualize
sample complexity
32
Chemical Imaging of Oil Shale (Grand Junction CO)
33
Comparison of Hydrocarbon and Carbonate Domains
Carbonate Image
Hydrocarbon Image
Red Color denotes High Concentration of Component
34
Principle Component Analysis Imaging of Printed Image
Small printed
symbols
Large overprint graphic
•
•
•
•
~ 26,000 spectra
35 micron pixel size
External reflectance
Complement visual
inspection with
chemical derived
distribution of inks
Splatter
Ink distribution
Base polymer
sheet
35
Small symbol ink
Two ink layers
Picta Wizards Particle Wizard
36
Polymer Laminate Film Analysis
• 7-layer laminate cross-section analysis by ATR-imaging
•
•
•
•
Adhesive layers of interest seem to be 5 micron thick
Sample prepared by Customer (two slices of 20 and 40 mm thickness )
Spectra in transmission show total saturation in CH stretching region
Micro ATR might be the solution
• Analysis of adhesive and barrier region
PP
EVOH
PP TiO2
PP TiO2
Adhesive material ?
37
Tip ATR Imaging Mode
• Identical to normal ATR mapping, but used with array detector
• ATR microscopy enhances the spatial resolution by a factor equivalent to the
refractive index of the crystal material (Germanium = 4.0)
• Single element detector analysis: the spatial resolution is ¼ of the aperture size (continuously variable,
depending on aperture size, down to 3 x 3 micron, at sample)
• Imaging detector analysis: the spatial resolution is ¼ of the element size (6 x 6 micron, at sample)
• By using the Ge Tip-ATR, the Nicolet iN10 MX provides 6 micron spatial resolution,
and about 150 spectra in typically less than 1 minute
• No real “size limit” since there is no spherical aberration
Crystal diameter at sample, 350 micron
Step 1
Step 2
Step 3
etc.
Field of view of detector
100 x 18 micron
38
Core Section Structure by ATR Imaging
Polypropylene
0.22
•
•
•
•
Collection time: less than 10 minutes
Resolution 8 cm-1
Time per step: 0.7 sec
ATR step – 6 microns
* Position (micrometers)=2471 µm ;-30775 µm POLYPROPYLENE LAYER
* Position (micrometers)=2408 µm ;-30755 µm ADHESIVE LAYER
0.20
0.18
0.16
2872.6
0.14
2838.8
Absorbance
• Measured area size: 210 x 70 micron
EVOH
Adhesive
0.12
0.10
2849.4
0.08
0.06
0.04
0.02
3100
3000
2900
Wavenumbers (cm-1)
39
2800
2700
Thermo ScientificTM Micro ATR Imaging Accessory
40
Thermo Scientific Micro ATR Imaging Accessory
Crystal
Arm
Pressure
Control
Lock
Pressure
Column
Fine Sample
Controls
Nicolet iN10MX
Nicolet Continuum
41
Imaging of Polymer Multi-layer Films
• Area Maps
• Classic multilayer film analysis
demonstrates high spatial resolution
• Total film thickness is 50 microns
• 4 layers
• System info:
• Nicolet iN10 MX
• Standard MCT detector
• 16 x 16 square aperture
 In AIR
• 4 x 4 micron pixel in Ge-ATR
• 4x additional magnification
w/ onboard folding optics
42
50 mm
Layered Polymer Film Line Map
• Line Maps of multilayer films
have all the information needed
• Chemical variation is in only
one dimension
• Total film thickness is 50 microns
• 4 layers
• System Info
• Nicolet iN10 MX
• Standard MCT Detector
• 10 x 2.5 micron pixel projection
 Rectangular aperture appropriate
for 1-D structure
• 2 micron step at sample.
43
Embedding
10 mm
PP
PE co print layer
PE
PP
Embedding
Hemispherical ATR Imaging of Automotive Coating
• Sample has layers
• 1-D variation
• Sample has
variation within
layers
• 2-D variation
• ATR Imaging
shows both sources
of variability
44
Spectra from Paint Chip Image
• Each spectrum each 8 scans (1 second), 6.25 micron spatial resolution
Abs
0.4
Inorganic Pigment (Talc) Position (micrometers)=-102 µm ;22 µm
0.2
-0.0
Abs
0.15
Inorganic Pigment (Calcium Carbonate) Position (micrometers)=-177 µm ;222 µm
0.10
0.05
Abs
-0.00
0.10
Organic Binder (Acrylic) Position (micrometers)=-477 µm ;-378 µm
0.05
0.00
Organic Binder (Epoxy) Position (micrometers)=323 µm ;-453 µm
Abs
0.2
0.1
4000
45
3500
3000
2500
2000
Wavenumbers (cm-1)
1500
1000
Summary
•
•
•
•
•
Infrared microscopes are designed to provide high spatial resolution
Versatile sampling options allow for a wide range of samples
Optical microscope capabilities provide enhanced contrast viewing
Chemical heterogeneity can be rapidly studied using imaging
New analysis tools aid non-microscopist to extract chemical and physical
information
46