Near Infrared (NIR) Spectroscopy
and Calibration in
Biomass Characterisation
Paul Geladi
Paul Geladi
Head of Research NIRCE
Unit of Biomass Technology and Chemistry
Swedish University of Agricultural Sciences
Umeå
Technobothnia
Vasa paul.geladi@btk.slu.se paul.geladi@syh.fi
Content
•
•
•
•
•
What is biomass?
What is NIR spectroscopy?
Examples
What is calibration?
Advanced topics
Content
• What is biomass?
•
•
•
•
What is NIR spectroscopy?
Examples
What is calibration?
Advanced topics
Non-food
Biomass
Food & feed
Bioenergy
Pulp and paper
Forestry
Building materials
Textiles
Consumer products
Feed and safety
Where is biomass found?
• Biotechnology
• Natural products
• Bioenergy
What is special about biomass?
•
•
•
•
•
O-H
C-H
N-H
C=O
different atom sizes = good
• IR+NIR energy = movements of bonds
O
H
O
H
H
O
O

H
H
H


H
H
Content
• What is biomass?
• What is NIR spectroscopy?
• Examples
• What is calibration?
• Advanced topics
Near Infrared Spectra (NIR)
Cosmic Gamma Xray Ultraviolet Visible NIR Infrared Microwaves
• 780-2500nm
• Suitable for all organic and bio materials
• Robust for industrial use
• Good penetration depth
• Many modes of measuring
• Powerful multivariate results
Near Infrared Spectra
• Fast
• Simple sample preparation
• Nondestructive
• Online for process applications
• Need for calibration
• Opportunity for data analysis
Near Infrared Spectra?
Visible
400nm
Near infrared
780nm
• Visible
• Infrared
• Raman
• Polarization
Infrared
Raman
2500nm
15000nm
Content
• What is biomass?
• What is NIR spectroscopy?
• Examples
•
•
•
•
What is calibration?
Advanced topics
Plans for a network of excellence
Acknowledgement
EXAMPLES 1
• Organic synthesis
• Liquid
• Fiberoptic transflectance
• Over time
Fibers in
Fibers out
Mirror
H2O
”Absorbance”
1.5
1
0.5
visible
0
400
600
800
near infrared
1000
1200
1400
1600
1800
2000
2200
2400
Wavelength
Organic synthesis over time
Absorbance
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
Wavelength
CONCLUSION 1
• Possible to follow a reaction over time
• Identify reagents, products, intermediates
• Reaction kinetics
EXAMPLES 2
• Whole grain and flour
• Solid
• FT-NIR reflectance
• Genetic variation
FLOUR
Pseudoabsorbance
0.55
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
1
1.5
2
2.5
x 10 -4
Wavelength
Pseudoabsorbance
WHOLE GRAINS
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0.35
0.3
0.25
1
1.5
2
2.5
x 10 -4
Wavelength
CONCLUSION 2
• Grain and flour different
• Genetic information
• Location information
• Accurate protein content
Where used?
• Food
• Feed
• Biofuel
• Fossil fuel
• Plastics
• Wood and pulp
• Environmental and waste
• Clinical and pharma
• In vivo
Rapid process monitoring for biofuels
• Canary reed grass
• Pellet / Briquette press
• The role of humidity
Biofuel energy unit
Briquette machine
Mixing drum with
window for measurement
Process NIR spectrometer
Reed canary grass
Briquette
Predict = determine quality ahead
• Humidity for briquette quality
• Other parameters (e.g. ash content,
energy, CO2) for energy production
Measure how?
• Location (how many? where?)
• How often?
• How detailed? Buckets? Single particles?
Content
• What is biomass?
• What is NIR spectroscopy?
• Examples
• What is calibration?
• Advanced topics
Spectral
property
Calibration
Model
Concentration
y
Calibration
a
Offset
Slope
Multivariate calibration
K
y
X
=
+
b
I
y = Xb + f
f
Why calibrate?
Spectrum
Spectrum
-measured in 1 min
-no sample preparation
-on-line possible
-noninvasive
-nondestructive
Concentration
Concentration
-sample preparation
-slow
-expensive
-waste chemicals
-destructive
Methods of data analysis
• Multivariate calibration
• Classification
• Multivariate image analysis
• Multiway analysis
• Neural nets
• Genetic algorithms
Content
•
•
•
•
What is biomass?
What is NIR spectroscopy?
Examples
What is calibration?
• Advanced topics
Instrumentation
Speed, Robustness
Simplified
instrumentation
High quality
instrumentation
Experimental
instrumentation
Complexity
Imaging / Spectroscopy
An image for each wavelength
A spectrum for each pixel
Table : Wavelength bands in some airborne / satellite imaging systems
Band/channelWavelength (nm)
SPOT-XS
LANDSAT-TM
1
500-590
450-520
2
610-680
520-600
3
790-890
630-690
4
760-900
5
1550-1750
6
10400-12500
7
2080-2350
8
-
JERS-OPS
520-600
630-690
760-860
760-860*
1600-1710
2010-2120
2130-2250
2270-2400
AVIRIS
224 bands
every 10nm
390-2500 nm
* bands 3 and 4 are a stereo pair.
SPOT-XS= (Système Probatoire d'Observation de la Terre) Image size 60x60 km;
resolution 20x20 m. (Panchromatic = B/W resolution 10x10 m).
LANDSAT-TM = (Thematic Mapper) Image size 185x172 km; resolution 30x30 m
JERS-OPS = Japanese Earth ResourcesSatellite - Optical Sensor 75x75km; resolution 18.3x25.4
m.
There is also 1.275 GHz radar.
AVIRIS = (Airborne Visible/Infrared Imaging Spectrometer ) Typical 512x614 pixels and
20x20 m resolution.
Resolution
• Wavelength
– reduction and selection
• Time
– fast product streams
– parallel measurements
• Space
–
–
–
–
0-D bulk analysis
1-D product streams
2-D images, microscopy
3-D tomography
What is new
and exciting?
• Spatial resolution imaging in 2D, 3D
• Fast streams in 1D
• Polarisation etc.
• Simplified instrumentation
• Advanced data analysis
• Database / search / control / presentation
Books to read
B. Osborne, T. Fearn & P. Hindle, Practical NIR
Spectroscoy 2nd ed., Longman Scientific &
Technical, Harlow, 1993, ISBN 0-582-09946-3
D. Burns & E. Ciurzak eds., Handbook of NearInfrared Analysis 2nd ed., Marcel Dekker, New
York, 200, ISBN 0-8247-0534-3
H. Siesler, Y. Ozaki, S. Kawata & H. Heise eds.,
Near-Infrared Spectroscopy, Wiley-VCH,
Weinheim, 2002, ISBN 3-527-30149-6