Transcript Methylation of acidic moieties to enable characterization in MAA based copolymer Rémi Giordanengo,(1) Stéphane Viel,(1) Manuel Hidalgo,(2) Béatrice Allard-Breton,(2) André Thévand (1) and.

Methylation of acidic moieties to enable
characterization in MAA based copolymer
Rémi Giordanengo,(1) Stéphane Viel,(1) Manuel Hidalgo,(2)
Béatrice Allard-Breton,(2) André Thévand (1) and Laurence Charles (1)
(1)
Aix-Marseille University – Marseille, France
(2) ARKEMA – Centre de Recherche Rhônes-Alpes – Pierre-Bénite, France
58th ASMS Conference, May 24, 2010, Salt Lake City
Copolymer Characterization by Mass Spectrometry
Nature of end-groups
Nature of MAA-MMA copolymer
X ,Y
block vs random
H3C
X
O
MAA
M = 86 Da
H3C
Y
n
m
OH O
OCH3
MMA
M = 100 Da
Composition
n,m
Two ionization techniques :
Molecular Weight
Mn , Mw
ESI and MALDI
2
ESI-MS
ESI(+)-MS spectrum
2 distributions :
613
[M + Na]+
[M + 16 + Na]+
513
MMA
527
499
∆ m/z 100
MMA
599 627
∆ m/z 100
MAA
MAA
∆ m/z 86
∆ m/z 86
713
699
727
3
ESI-MS
ESI(+)-MS spectrum
327
427
313
413
MX, MY unknown
613
513
527
499
599 627
699 713
685 727
n, m ?
4
ESI-MS/MS
MS/MS requested to determine the actual values of n and m
Dissociation rules of MAA-MMA copolymers in negative and positive mode ESI :
 water elimination
+
+
Na
Na
- 18 Da
O
O HO
- H2O
O
O
O
O
H
Between two consecutive neutral MAA → MAA/MAA pair in the polymeric chain
 methanol elimination
+
+
Na
Na
- 32 Da
O
O
H3CO
O
- CH3OH
O
O
O
H
Between neutral MAA and MMA→ MAA/MMA pair in the polymeric chain
The number of water and methanol losses is monitored to reveal the number
and arrangement of MAA and MMA units in the selected precursor ion
Giordanengo, R. et al. J. Am. Soc. Mass Spectrom. 2009, 20 (1), 25-33 ; Giordanengo, R. et al. Rapid Commun.
Mass Spectrom. 2009, 23 (11) 1552-1567 ; Giordanengo, R. et al. Anal. Chim. Acta 2009, 654, 49-58
5
ESI-MS/MS
m/z 499 (2 ; m+1)
Only one loss of water
- MeOH
- H2O
Only one MAA/MAA pair
2 MAA units
Neither
Only one
water
loss
nor
ofmethanol
methanolloss
in MS/MS spectra of precursor
ion in the first column
Only one MAA/MMA pair
1No
MMA
unit
MAA
unit
m+1
n == 01
6
ESI-MS/MS
m/z 771 (4;2)
m/z 753
m/z 735
m/z 739
m/z 721
m/z 771
- H2O
m/z 707
m/z 689
- MeOH
1 loss of
H2O of H2O
2 consecutive
losses
Different dissociation routes
2 MAA-MAA
losses of MeOH
pairs
from the same precursor ion
1 MAA-MAA
pair
4 MAA units
MX + MY = 204 Da 2 MAA-MMA pairs
M and M unknown 2 MMA units
X
Y
Random nature of the studied
MAA-MMA copolymer
7
Limitations of the ESI-MS/MS Approach
Dissociation of MAA-MMA co-oligomer sodiated adducts allows :
ESI-MS(/MS)
MAA-MMA
(n, m)
Nature
(MX + MY)
 To reach the co-monomeric composition of co-oligomers
 To reveal the random nature of the studied MAA-MMA copolymer
 To determine the sum of the end-group masses (MX + MY)
However :
 The lack of specific fragmentation does not allow the end-groups to
be structurally characterized (contrary to what is usually obtained in
the case of homopolymers such as PMMA)
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Other ESI-MS Limitations
ESI-MS spectrum of the MAA-MMA copolymer :
 Distribution parameters largely underestimated as compared to
NMR data (Mn 3100 Da)
 Same phenomenon in ESI of constitutive homopolymers PMMA
and PMAA
Signal only in the low m/z range indicating
a strong bias toward low mass oligomers
PMMA 1590
PMAA 1250
Mw (1+) 865
Mw (1+) 612
Mw (2+) 1592
Mw (2+) 728
values
of Mnfor
and
w
Strong bias toward Wrong
low mass
oligomers
allM
acrylic
polymers
Uncorrect MAA/MMA ratio
Haddleton, D. M.; Feeney, E.; Buzy, A.; Jasieczek, C. B.; Jennings, K. R., Chemical Communications 1996, (10),
1157-1158.
9
Limitations in Terms of Molecular Weight Determination
MALDI-MS :
 In contrast, MALDI-MS spectra of constitutive homopolymers
PMMA and PMAA are more realistic
 However, no interpretable signal obtained in MALDI for the MAA-MMA
PMMA 1590
PMAA 1250
copolymers
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Strategy
In contrast to results obtained for MAA-MMA copolymers:
 End-groups characterization is possible during CID of PMMA
homopolymers
O
O
Si
CH
N
Si
N
H2
C
N
N
N
N
OH
O
R
R MALDI
 Distribution
parameters
can be achieved by
of PMMA
homopolymers
Si
H2
C
N
N
CH3OH
Si
O
H3C
N
O
O
STRATEGY
N
R
H3C
O
N2
R
OCH3
Transform MAA-MMA copolymers into PMMA homopolymers by
methylating all MAA units
Experimental
 ~ 50 mg of MAA-MMA copolymer in 20 mL of a MeOH/H2O mixture (19/1, v/v)
(stirred 2h at room temperature)
 Addition of an excess of trimethylsilyldiazomethane (stirred 3h at room temperature)
 Drying at 30°C overnight
Couvreur, L.; Lefay, C.; Belleney, J.; Charleux, B.; Guerret, O.; Magnet, S. Macromolecules 2003, 36, 8260-826
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Strategy
Derivatization of MAA-MMA copolymers
to determine distribution parameters
12
Methylation of PMAA Homopolymers
MALDI(+)-MS spectrum
methylated
PMAA 1700
PMAA 1700
Methylation
1
1250
1132
- A single PMMA distribution is obtained,
Methylated
PMAA acid functions of PMAA
indicating
all acrylic
have beenMmethylated.
MALDI
MwSEC
MwPGSE
w
- Good signal-to-noise ratio is measured from
1445 laser fluence
1231
1452
low
(~ 40%).
2
1700
1487
1966
1634
1701
3
3150
1951
3654
2579
2928
4
6600
4546
7664
5620
6311
- Complex MS spectrum due to the
ability of
PMAA
+
PMAA to bind numerous Na cations.
PMAA
MwSEC
MwMALDI
- High laser fluence (65%).
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Methylation for Molecular Weight Determination
800
No signal obtained
before methylation
400
2000
3500
5000
1000
AfterNMR
methylation
Mw can be determined by MALDI and PGSE
600
Intense MALDI-MS signal
Methylated Copolymer
200
MAA/MMA
2000
Copolymer
MnMALDI
MnNMR
MwMALDI
MwPGSE
Mw calculated
from MwMALDI
Mw calculated
from MwPGSE
3200
3150
4360
5170
4110
4870
4000
6000
Giordanengo, R.; Viel, S.; Hidalgo, M.; Allard-Breton, B.; Thevand, A.; Charles, L. J. Am. Soc. Mass Spectrom.
2010, 21 (6) 1075-1085.
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Strategy
Derivatization of MAA-MMA copolymers
for end-group characterization
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Methylation for End-Group Characterization
ESI(+)-MS :
methylated
MAA-MMA
MAA-MMA
Methylation
[M + Na]+
(MX + MY) = 204
[M + 16 + Na]+
(MX + MY) = 220
[M + Na]+
(MX + MY) = 204
[M + 16 + Na]+
(MX + MY) = 220
After methylation :
 ESI-MS simplified
 A single PMMA distribution is obtained indicating all MAA units have been methylated
 No modification of the end-groups during the methylation reaction
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Methylation for End-Group Characterization
ESI(+)-MS/MS of the methylated MAA-MMA copolymer : m/z 827
Dissociation rules of PMMA homopolymers in positive mode ESI (1) :
Y
X
n
CO2CH3
CO2CH3
CO2CH3
CO2CH3
-CO2CH3
X
n
.
CO2CH3
X
n
CO2CH3
Series F
-CO2CH3
.
Y
+
C
m
CO2CH3
+
C
+
C
m
.
CO2CH3
X
CO2CH3
n
CO2CH3
Y
m
CO2CH3
Series A
+
C
X
n
CO2CH3
.
CO2CH3
Series B
m
+
C
CO2CH3
Y
+
C
CO2CH3
Y
m
+
C
CO2CH3
Series D
Jackson, A. T.; Yates, H. T.; Scrivens, J. H.; Critchley, G.; Brown, J.; Green, M. R.; Bateman, R. H. Rapid Commun. Mass Spectrom. 1996,
10, 1668 ; Jackson, A. T.; Yates, H. T.; Scrivens, J. H.; Green, M. R.; Bateman, R. H. J. Am. Soc. Mass Spectrom. 1997, 8, 1206
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Methylation for End-Group Characterization
ESI(+)-MS/MS of the methylated MAA-MMA copolymer :
Dissociation rules of PMMA homopolymers in positive mode ESI (2) :
CO2CH3
H3CO2C
+
C
X
n
H H3CO2C
X
m Y C+
CO2CH3
n
CO2CH3
CO2CH3 H
CO2CH3
mY
CO2CH3
CO2CH3
- HCO2CH3
- HCO2CH3
Y
X
n
CO2CH3
Series C
CO2CH3
+
C
m
CO2CH3
Series D
Y
+
C
X
n
CO2CH3
Series F
m
+
C
CO2CH3
CO2CH3
+
C
CO2CH3
Series E
Jackson, A. T.; Yates, H. T.; Scrivens, J. H.; Critchley, G.; Brown, J.; Green, M. R.; Bateman, R. H. Rapid Commun. Mass Spectrom. 1996,
10, 1668 ; Jackson, A. T.; Yates, H. T.; Scrivens, J. H.; Green, M. R.; Bateman, R. H. J. Am. Soc. Mass Spectrom. 1997, 8, 1206
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Methylation for End-Group Characterization
Application of the dissociation rules of PMMA homopolymers in positive mode ESI :
m/z 827
A0
Most intense fragment ions:
Series A or B
A1
The two most intense fragment ions
could be identified to Series A,
revealing Y = H
.
H
m
CO2CH3
+
Na
CO2CH3
A0 : m/z 110
A1 : m/z 210
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Methylation for End-Group Characterization
Application of the dissociation rules of PMMA homopolymers in positive mode ESI :
m/z 827
A0
Since Y = H, product ions D
and E can be assigned
A1
Series E
D
HH of Y
Validation of the nature
+
mm
CO2CH3
M = 1CO
Y 3
CO2CH
Na
CH3
2
CO2CH
3
Y=H
E0 : m/z 209
D2 : m/z 265
E1 : m/z 309
D3 : m/z 365
E2 : m/z 409
D4 : m/z 465
E3 : m/z 509
D5 : m/z 565
E4 : m/z 609
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Methylation for End-Group Characterization
Application of the dissociation rules of PMMA homopolymers in positive mode ESI :
MX + MY = 204, with MY = 1 → MX = 203
Based on MX = 203,
product ions B, C and F can be identified
Series
Series FC
B
XXX
nn
.
++
Na
Na+
Validation of
CO CH
CO22CH
CH33
CO
2
3
CO2CH
CH3
CO
2
3
MX = 203
C
m/z 381
425
F
B110 :: m/z
226
C
525
F
B221 :: m/z
m/z 481
326
C33 :: m/z
m/z 581
625
F
C4 : m/z 725
21
Methylation for End-Group Characterization
2 additionnal
at m/z
715 et m/z 683
Use of a sulfurated
agentproduct
duringions
thedetected
copolymer
synthesis,
allow to validate the structure proposed for X
2-ethylhexyl
thioglycolate (M = 204 Da)
Proposed
structure for X
Proposed
structure for X
Na+
Na+
715
Na+
683
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NMR Analysis
NMR 1D (1H, 13C) and 2D (COSY, HSQC, HMBC, DOSY) analysis
Proposed structure of X :
1'
2'
3
4'
3'
2
4
1
O
O
5
6
CH3
7
S
CH2
MAA-MMA
COOR
X end-group
Nature
δ13C (ppm)
δ1H (ppm)
1
CH3
14.6
0.96
2
CH2
24.0
1.38
3
CH2
30.0
1.37
4
CH2
31.4
1.40
1’
CH3
11.4
0.98
2’
CH2
24.7
1.45
3’
CH
40.0
1.65
4’
CH2
68.3
4.10
5
C(O)
172.0
-
6
CH2
35.5
3.27
7
CH2
45.9
2.93
2.75
Validation of the structure of the end-groups
Giordanengo, R.; Viel, S.; Hidalgo, M.; Allard-Breton, B.; Thevand, A.; Charles, L. Rapid Commun. Mass
Spectrom. , in press
23
Conclusion
Methylation of MAA-MMA copolymers allows :
MAA-MMA
MAA-MMA
ESI-MS(/MS)
MALDI-MS
(n, m)
Methylation
Nature
(MX + MY)
failed
Methylation
MX , MY
Mn , Mw
 A complete microstructural characterization
 The distribution parameters to be determined (with the help of
NMR data)
consistently with NMR results
24
Acknowledgments
 The organisation committee
 The Spectropôle, analytical facility of Aix-Marseille University, for
the special access to the instruments
 ARKEMA, for the financial support
 SACS and C&S members
 Thank you for your attention
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