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