nuclear magnetic resonance (nmr) for process analysis...
TRANSCRIPT
Nuclear Magnetic Resonance (NMR) for Process Analysis with Potential Application on NeSSI™ with an Overview of Additional Activities in the McCarthy Research Group
Michael McCarthy and David Lavenson
Collaborators:Collins Univ. of Maine; Han UCSB;J.C. Edwards Process NMR;R. Powell UCD; T. Jeoh UCDJ.H.Walton UCD
• Experimental and physics-based modeling investigations of transport phenomena relevant to product and process
• Real-time measurement of quality attributes• Development/evaluation of novel magnetic resonance equipment to
enable process control
Research Overview
Modeling
Rapid Quality Measurement
HardwareCPAC
NMR and MRIStrengths- Chemical identification- Structure determination- Medical imaging- Microscopy imaging- Noninvasive- High speed…
Past Limitations: Not suitable for industrial environmentNot portableLow sensitivityRelationship of measurement to quality?
Strawberry Milk Chocolate Milk 4 Averages
Chocolate Milk 20 Averages
http://www.bruker-biospin.com/nmr_magnets_us2.html?&L=0&print=
Mass Transport/Quality/Equipment• Component migration
– Almond oil migration in chocolate– Controlled release of bioactives & water mobility in restricted
geometries– Enzyme mixing/diffusion in cellulose suspensions
• Quality Attributes– Pomegranates - defects– Tomatoes - defects– Rheological property measurement (in-line)
• NMR equipment (prototype magnets)– Aspect MR– ABQMR (single-sided)– Others
Designing Controlled Release Systems by using Magnetic Resonance Imaging
• Whey Protein Gels in simulated intestinal(pH~ 7.3) and gastric juices (pH~ 1.2)
Whey Protein Gel(Food matrix)
Whey protein beads containing oil(delivery systems)
Crosslinking the gels with divalent ions affect release of the active agents
Crosslinking in MnCl2 sol’n Crosslinking in CaCl2 sol’n
Cross-linked region
T2 Relaxation Spectrums give information about the crosslinking
Mathematical Modeling of Swelling Controlled Delivery Systems
c=concentration(g water/g gel)
Fick’s 2nd law with moving Boundaries
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Day 1 Day 2
Day 4 Day 11
Chocolate
Almond Butter
Preliminary MR images of Almond butter-chocolate samples: Oil migration shown by decreasing signal intensity of almond butter region and increase in chocolate
Seed
Freeze damage
Fast Spin Echo proton images of Clementine citrus fruit with defects. Freeze damage is shown in the image on the left and a seed is shown in the image on the right. Both images were taken on a 1 Tesla permanent magnet based spectrometer, 68 mm field-of-view (128 x 128),18 mm slice thickness, one acquisition
WWW.ASPECT-MR.COM
“Alpha” Unit
Packing house “beta” unit
One Tesla field strength magnet for MRI sorting of citrus fruit being installedin the packing line. The three tubes extending from the magnet will eachhave a lane of fruit feeding into the system. The three lanes will be imagedsimultaneously. One image from the system is shown on the right. (Photoand image courtesy of Uri Rapoport Aspect AI Ltd., Netanya, Israel).
Measure material rheological properties• Previously in CPAC funded work
(leveraged with NSF funding) we demonstrated– Rapid rheological measurement (~1 minute)– Up to 3 orders of magnitude in shear rate
range – Accuracy equivalent to research grade
rheometers
Next steps in MRI rheometerdevelopment• Goal in the next year is to measure a
complete rheogram in 50 ms • Modify software for data analysis from one
requiring operator intervention to fully automated – partially completed
• Include measurement of slip and yield stress in automatic analysis – partially completed
Project Goals: • characterize rheology and mixing in biomass
suspensions • complete the integration the DNP system into a NeSSI
system and flow the polarized material into a NeSSImounted microcoil and acquire an NMR signal;
• test micro-scale rf coils produced by Scott Collins on a prototype process spectroscopy magnet at Process NMR Associates and determine if the spectral resolution can be improved;
• design, build and test a curved rf coil for improving the signal-to-noise in single-sided NMR applications
Mixing non-Newtonian Fluids
• Need to use non-conventional methods– Stretching and folding (chaotic advection)
• Split and recombine (SAR) mixer– Generates striations/layers each mixing element
Mixing visualized in the SAR mixer
Spectra from John Edwards, Process NMR
Current process NMR magnets have limited resolution and shimming is temperature dependent
Propose taking microcoils and samples to Process NMR to test new magnet built by Aspect for process spectroscopy.Can resolution be improved with microcoils? How stable is the shim as temperature changes?
Evaluating new spectroscopy magnet
• Measure spectra using microcoil
• Move microcoil in the shimmed field to achieve improved resolution
• Samples from sponsors or suggestions?
~750 micron ID solenoid, tuned to 58.3 MHzProduced on HPLC tubing
Summary: Answer the following questions• How much can we improve S/N in single-
sided NMR using coils matched to the shape of the sample?
• Are microcoils useful for improving spectral resolution?
• Measure diffusion and mixing of enzymes in high solids cellulosic biomass suspensions
Poster Introduction byDavid Lavenson1. Using MRI to spatially resolve concentration
profiles of diffusing species in static cellulosic fiber beds– Use of paramagnetic tracers – MnCl2 and Gd-
BSA
2. Using MRI as a tool for measuring velocity profiles of high solids cellulose suspensions– Velocity encoded spin echo images (flow
imaging)
The Importance of Biomass Transport Phenomena
Lignocellulosic Biomass
HydrolysisCellulases Hemicellulases
Sugars (Hexoses, Pentoses)
Fermentation Micro organism (wild or recombinant)
Separation Main Product
By-products
Pretreatment
•Alcohols
•Acids
•Amino acids
•Industrial chemicals
(Fuel for boiler, Animal feed, Industrial chemicals)
Why is Diffusion Important for Biofuels?
Concentration profiles Diffusion
models based on fiber
characteristics
Time scales for diffusion transport in cellulosic fiber
beds
Improvements to Mixing Design
MRI measurements
Tortuosities
Effective diffusivities
Adsorption isotherms
MRI Measurements
Image of diffusion vial with reference vial. Diffusion vial doped with Gd-
BSA tracer molecules at known concentration. Reconstruction of
image using MATLAB
ZZ=0
Z=L
6 images of adsorption vials (alongside reference vials) with
increasing amounts of PCS fibers added. Reconstruction of image
using MATLAB.
Experimental and Numerical Concentration Profiles
Imaging Flow of Cellulose Suspensions in a Pipe
Why is Rheology Important for Biofuels?
Pressure drop
Velocity profiles
Generalized Newtonian
models
Power and Mixing
Requirements
Operating Costs$$$
MRI/flow loop measurements
Viscosity
Yield Stress
Flow Imaging
1. Reservoir
2. Mixer
3. Pump
4, 9. Pressure taps
5. PMMA tube
6. Permanent magnet enclosure
7. MRI coil
8. Return hose
10. Bypass valve
11. Differential pressure transducer
Velocity Profiles: Medium-Length Fibers
C = 7.05% (w/w)
C = 3.14% (w/w)
Solka Floc C100 fibers
Length (LW) = 0.349 mm
Width (LW) = 31.7 um
Acknowledgements• Lu Zhang• Sandra Garcia• Mecit Oztop• Emilio Tozzi• David Lavenson• Eiichi Fukushima,
ABQMR, Inc.• John Edwards, Process
NMR
• Uri Rapoport, ASPECT Magnet Technologies Ltd. www.aspect-mr.com
• USDA• Almond Board of California• P & G• ConAgra Foods• Paramount Citrus
Association• CPAC• POM Wonderful