6/10/2011 1 Tandem Mass Spectrometry of Synthetic Polymers Árpád Somogyi Department of Chemistry and Biochemistry University of Arizona Summer Workshop Problems with polymer analysis • Sample preparation – Several polymers are not well soluble in conventional solvents – Solventless technique – Cationizing with Na + , K + , and Ag + by spiking – Synthesis of tailor (home) made matrices • Degradation during ionization (especially with MALDI) – Photodissociation in MALDI (MALDI/ESI comparison desirable) • End group analysis reliable but better to have high resolution/accurate mass (FT-ICR)
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Tandem Mass Spectrometry of Synthetic Polymers
Árpád Somogyi
Department of Chemistry and BiochemistryUniversity of Arizona
Summer Workshop
Problems with polymer analysis• Sample preparation
– Several polymers are not well soluble in conventional solvents
– Solventless technique– Cationizing with Na+, K+, and Ag+ by spiking– Synthesis of tailor (home) made matrices
• Degradation during ionization (especially with MALDI)– Photodissociation in MALDI (MALDI/ESI comparison
desirable)
• End group analysis reliable but better to have high resolution/accurate mass (FT-ICR)
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Molecular weight distribution defines polydispersit y of polymers
Polydispersity (PD) = Mw/Mn
Polystyrenewith Ag+
Zhu, H.; Yalcin, T.; Li, L. JASMS, 1998, 9, 275-281.
Somogyi, et al., Macromolecules, 2007, 40, 5311-5321.
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Practical importances of phenanthrolinePractical importances of phenanthroline--functional ized PEGsfunctionalized PEGs
� stabilization of magnetic nanoparticles(e.g. Fe3O4)
�hydrofilic networks by complex formation
KékiKéki, , S.; S.; KukiKuki, , ÁÁ.. KukiKuki;; Nagy, Nagy, M.; M.; Nagy, L.; Nagy, L.; ZsugaZsuga, M., M.JASMSJASMS, 2010, , 2010, 2121, 1561, 1561--1564.1564.
Change of Change of the the absorbance at 515 nm absorbance at 515 nm versus versus molar ratio of the added molar ratio of the added Fe(II)Fe(II)--ions and phenanthroline functions of ions and phenanthroline functions of PEGsPEGs
0
0.2
0.4
0.6
0.8
1
1.2
350 450 550 650
λλλλ (nm)
Abs
orba
nce
CT transition
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 0.2 0.4 0.6 0.8 1
[Fe2+]/[phen]
Abs
orba
nce
(515
nm
)
▲εεεε≈10300 M-1cm-1♦εεεε≈11090 M-1cm-1
Fe2+ : PEG_phen = 1: 3
Fe2+ : phen_PEG_phen = 2: 3
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Synthesis of phenanthrolineSynthesis of phenanthroline--functionalized PEGsfunctionalized PEGs
N N
HO
N N N N
HOO
cc. H2SO4, reflux, 1 h
50% NaOH, pH=7
reflux, 72 h
SOCl2, abs. tolueneCH3 O CH2 CH2 OH
n
Cl
n
CH3 O CH2 CH2
N
N
OCH3 O CH2 CH2
nn
CH3 O CH2 CH2 Cl NaH, abs. DMF
reflux, 48 h+
N N
HO
NaH, abs. DMF
reflux, 48 h+
n-1
CH2 O CH2 CH2 ClCH2Cl
nN
N N
NCH2 CH2 OO
2
(PEG_phen)
(phen_PEG_phen)
(Mn = 1100 g/mol)
(Mn = 1500 g/mol)
ESIESI--MS spectrum of Fe(PEG_phen)MS spectrum of Fe(PEG_phen) 332+2+
ESIESI--MS intensity distribution of PEG_phen and Fe(P EG_phen)MS intensity distribution of PEG_phen and Fe(PEG_ph en)332+2+
+Fe(II)+Fe(II)
Fe2+ + L i + L j + Lk FeL i+j+k2+ (n=i+j+k)
Theoretical model:Theoretical model:
0
0.02
0.04
0.06
0.08
0.1
0.12
15 20 25 30 35 40
number of EO units
Pro
babi
lity
0.0
0.2
0.4
0.6
0.8
1.0
60 80 100 120
number of EO unitsN
orm
aliz
ed in
tens
ity
measured
simulated
kj
kjiin PPPP ∑
∞
==
1,,
ESIESI--MS/MS of Fe(PEG_phen)MS/MS of Fe(PEG_phen) 332+2+
727.
35
1493
.31
2193
.30
0
100
200
300
Intensity
200 400 600 800 1000 1200 1400 1600 1800 2000 m/z
Fe(PEG_phen) 32+ Fe(PEG_phen) 2
2+ + PEG_phen
Fe(PEG_phen) 22+ Fe(PEG_phen) 2+ + PEG_phen
0
0.2
0.4
0.6
0.8
1
10 30 50 70
number of EO units
norm
alze
d in
tens
ity
80 V
90 V
simulated
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Very recent polymer MS and MS/MS articles in JASMS (April, 2011)
Szyszka, R.; Hanton, S. D.; Henning, D.; Owends, K. G. “Development of a CombinedStandard Additions/Internal Standards Method to Qua ntify Residual PEG in Ethoxylated
Surfactants by MALDI TOFMS” JASMS, 2011, 22, 633-640.
Song, J.; Siskova, A.; Simons, M. G.; Kowalski, W. J.; Kowalczuk, M. M.; van den BrinkO. F. “LC-Multistage Mass Spectrometry for the Char acterization of Poly(Butylene
Fouquet, T.; Humbel, S.; Charles, L. “Tandem Mass S pectrometry of Trimethylsilyl-TerminatedPoly(Dimethylsiloxane) Ammonium Adducts Generated b y Electrospray Ionization”