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Near Infrared (NIR) Spectroscopy and Calibration in
Biomass Characterisation
Paul Geladi
Paul Geladi
Head of Research NIRCEUnit of Biomass Technology and ChemistrySwedish University of Agricultural SciencesUmeåTechnobothniaVasa [email protected] [email protected]
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
Biomass
Non-food
Food & feed
Bioenergy
Pulp and paper
ForestryBuilding materialsTextiles
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 H
O
H H
O
H H
O
H H
Content
• What is biomass?
• What is NIR spectroscopy?• Examples
• What is calibration?
• Advanced topics
Near Infrared Spectra (NIR)
• 780-2500nm
• Suitable for all organic and bio materials
• Robust for industrial use
• Good penetration depth
• Many modes of measuring
• Powerful multivariate results
Cosmic Gamma Xray Ultraviolet Visible NIR Infrared Microwaves
Near Infrared Spectra
• Fast
• Simple sample preparation
• Nondestructive
• Online for process applications
• Need for calibration
• Opportunity for data analysis
Near Infrared Spectra?
• Visible
• Infrared
• Raman
• Polarization
Visible Near infrared Infrared Raman
400nm 780nm 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
400 600 800 1000 1200 1400 1600 1800 2000 2200 24000
0.5
1
1.5
Wavelength
”Absorbance” H2O
visiblenear infrared
400 600 800 1000 1200 1400 1600 1800 2000 2200 24000
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Wavelength
Absorbance Organic synthesis over time
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
1 1.5 2 2.5
x 10-4
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
Wavelength
Pseudoabsorbance FLOUR
1 1.5 2 2.5
x 10-4
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
Wavelength
Pseudoabsorbance WHOLE GRAINS
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 unitBriquette machine
Mixing drum withwindow for measurement
Process NIR spectrometer
Reed canary grassBriquette
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
Calibration
Concentration
Spectralproperty Model
y
Offset
Slope
Calibration
Xy
I
K
f
b
= +
y = Xb + f
Multivariate calibration
Why calibrate?
Spectrum Concentration
Spectrum -measured in 1 min-no sample preparation-on-line possible-noninvasive-nondestructive
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
High qualityinstrumentation
Simplified instrumentation
Experimentalinstrumentation
Complexity
Speed, Robustness
Instrumentation
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 JERS-OPS AVIRIS
1 500-590 450-520 520-600 224 bands2 610-680 520-600 630-690 every 10nm3 790-890 630-690 760-860 390-2500 nm4 - 760-900 760-860*5 - 1550-1750 1600-17106 - 10400-12500 2010-21207 - 2080-2350 2130-22508 - - 2270-2400
* 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 mJERS-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 newand 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 Near-Infrared 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