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Development of Analytical Methods using
Low Field NMR (LFNMR)
Luiz Alberto ColnagoEmbrapa Instrumentation
Brazilian AgriculturalResearch Corporation
Workshop Biorefineries 2010Recent Advances and New Challenges
Firjan, RJ, 10/11/2010
2
Nature 466, 554-556 (2010)
Food: The global farmWith its plentiful sun, water and land, Brazil is quickly surpassing
other countries in food production and exports. ….
Jeff Tollefson
25 % of GDP
60 Billion dollars (30% exp.)
“if one wants to know the primary reason of Brazil´s success in three words, they are Embrapa, Embrapa, Embrapa”,
4
Brazil 1st exporter
High variability
Commodities- millions of tons
Quality characterization/certification
High-throughput Agri-industrial sensor
- NMR –5
Superconducting Magnet
Transmitter /receiver
High resolution NMR Spectroscopy
Computer
HR-NMR application (solution)
Structure determination
Organic Synthesis
Natural Products
Materials
etc.
codeín
(a)Too expensive,
(b)too delicate for a factory environment
c)too slow for sample moving (2 m/s).
(d) Insufficient time to polarize the samples
(e) High skilled operators
distance (d= 5T1v ) in the magnet
(for v= 2 m/s, T1 = 1 s, d =10 m)
Why conventional NMR fail industrial sensor?Hills and Wright, JMR, 178,193-205, 2006
8
9
Too expensive,
too delicate
High skilled operators
Low resolution NMR - LRNMR
2- Insufficient polarization time
1-Too slow
LRNMR Problems
10
11
LRNMR Problems : Too slow
Poor S/N
Signal average:S/N=(n)1/2
Quantitative measurements = 5T1
Total time: seconds to minutes
Continuous Wave Free Precession (CWFP )
Azeredo et al, Anal. Chem. 72,2401-2405, 2000
n
Solution - LRNMR (S/N and T1)
Tr= 300 s
Mc=M0T2/T1+T2
Conventional NMR and CWFP
700 ms
0.3 ms
Soybean oilT1=140 msT2 =50 ms T2*= 0.5 ms
56 ms
29 ms
0.9 ms
CWFP=Tr<T2*
SSFP
-1.0 -0.5 0.0 0.5 1.0
(b)
H
G
F
E
D
C
B
A
t (msec)
SS
FP
Am
pli
tud
e
-1.0 -0.5 0.0 0.5 1.0
(b)
H
G
F
E
D
C
B
A
t (msec)
SS
FP
Am
pli
tud
e
-1.0 -0.5 0.0 0.5 1.0
(b)
H
G
F
E
D
C
B
A
t (msec)
SS
FP
Am
pli
tud
e
-1.0 -0.5 0.0 0.5 1.0
(b)
H
G
F
E
D
C
B
A
t (msec)
SS
FP
Am
pli
tud
e
-1.0 -0.5 0.0 0.5 1.0
(b)
H
G
F
E
D
C
B
A
t (msec)
SS
FP
Am
pli
tud
e
T1=T2, Mc=0.5M0
Azeredo et al, Anal. Chim. Acta 478, 313, 2003
Enhance S/N
a) Conventional
0 5 10 15 20
(a) time (ms)
0.0 0.2 0.4 0.6 0.8
(b) time (ms)
b) CWFP
0 20 40 60 80 1000
1
2
3
CW
FP
Am
pli
tud
e (
au
)
Oil % (W/W)
Azeredo et al, Anal. Chem. 72,2401-2405, 2000
Online CWFP NMR
Flow effect on CWFP signal
(Azeredo et al, Phys. Rev. E. 64, 016309-1, 2001)
Online NMR
Colnago et al, Anal. Chem. 79, 2382, 2007
Online NMR
99 seeds V=13 cm/s (+ 20,000 samples/h)
0 2 4 6 8 10 12 14
0
20
40
60
80
100
120
140
CW
FP
am
pli
tud
e (
au
)
Time (s)
r2 = 0.96
Biodiesel program, seeds high oil content100.000 SAMPLES
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
10 20 30 40 50 60 70 80 90
CWFP amplitude (au)
Oil
ma
ss
(g
)
Online Quality Analysis
CPMG –T2
0.0 0.5 1.0 1.5 2.0
Time (s)
(+ 1000 samples/h)
CPMG Analysis
0,0 0,5 1,0
0,0
0,5
1,0
D
C
BA
CP
MG
ech
o a
mp
litu
de
(a
u)
Time (s)
A-linseed; B- Soybean; C- Macadamia; D- Castor bean
Prestes et al,, Anal. Chim. Acta, 596, 325-329, 2007
39 42 45 48 51 54 57
42
45
48
51
54
b)
Ce
tan
e n
um
be
r fr
om
NM
R
Cetane number calculated from GC
Multivariate analysis (PLS)
Prestes et al, Anal. Chim. Acta, 596, 325-329, 2007
80 100 120 140 160 180
80
100
120
140
c)
IV
nu
mb
er
fro
m N
MR
IV number calculated from GC
25
High oleic acid peanuts (Margarine substitute)
3 x 4000 samples IAC
0 10 20 30 40
0,14
0,16
0,18
T2 (
ms)
Seed number
Mobile RMN
But not the for: inside-out, ex-situ, remote, single-sided, one-sided access Spectrometer
conventional
unilateral (U shape)
B0B1
NS
SN
N S NS
B0B1
Conventional NMR – Sample size depend on bore or gap size.
Ex. MOUSE (MObile Universal Surface Explorer) *
Unilateral RMN
Applications at Embrapa
Monitor biodiesel reaction
0 20 40 60 80 100
40
50
60
70
80
90
100
110
T* 2 (
ms)
Biodiesel Percentage0 20 40 60 80 100 120
40
50
60
70
80
90
100
110
T* 2 (
ms)
Reaction Time (ms)
Monitor biodiesel reaction
ANG. CHEMIE-INTERNATIONAL EDITION, 49 ,4133, 2010
Collaborations
Prof. Mario Engelsberg – DF/UFPe
Prof. Rodrigo B. V. Azeredo – DQO/UFF
Prof. Tiago Venâncio- DQ-UFSCar
Prof. Lucio L. Barbosa IQ-UFES
Graduate Students-USP
Fabiana Diuk
Antonio Marchi Netto
Pos-Doc.
Lucinéia Vizzotto
Acknowledgments to brazilian funding agencies
34
MRI-Halbach1.2m Prepol, 0.5 principal magnet, 10 cm bore
Insufficient polarization time
www.spinlock.com.ar
