Methylation of acidic moieties in poly(methyl methacrylate-co-methacrylic acid) copolymers for end-group characterization by tandem mass spectrometry

2010 ◽  
Vol 24 (14) ◽  
pp. 1941-1947 ◽  
Author(s):  
Rémi Giordanengo ◽  
Stéphane Viel ◽  
Manuel Hidalgo ◽  
Béatrice Allard-Breton ◽  
André Thévand ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Methyl Methacrylate ◽  
Methacrylic Acid ◽  
Tandem Mass ◽  
Poly Methyl Methacrylate ◽  
Methacrylic Acid Copolymers ◽  
End Group

Tandem Mass Spectrometry Characteristics of Polyester Anions and Cations Formed by Electrospray Ionization

2005 ◽  
Vol 11 (2) ◽  
pp. 243-256 ◽  
Author(s):  
Mark A. Arnould ◽  
Rafael Vargas ◽  
Rita W. Buehner ◽  
Chrys Wesdemiotis
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
Mass Spectra ◽  
Quadrupole Ion Trap ◽  
Tandem Mass ◽  
Negative Mode ◽  
End Groups ◽  
Positive Mode ◽  
End Group

Electrospray ionization of polyesters composed of isophthalic acid and neopentyl glycol produces carboxylate anions in negative mode and mainly sodium ion adducts in positive mode. A tandem mass spectrometry (MS/MS) study of these ions in a quadrupole ion trap shows that the collisionally-activated dissociation pathways of the anions are simpler than those of the corresponding cations. Charge-remote fragmentations predominate in both cases, but the spectra obtained in negative mode are devoid of the complicating cation exchange observed in positive mode. MS/MS of the Na+ adducts gives rise to a greater number of fragments but not necessarily more structural information. In either positive or negative mode, polyester oligomers with different end groups fragment by similar mechanisms. The observed fragments are consistent with rearrangements initiated by the end groups. Single-stage ESI mass spectra are also more complex in positive mode because of extensive H/Na substitutions; this is also true for matrix-assisted laser desorption ionization mass spectra. Hence, formation and analysis of anions might be the method of choice for determining block length, end group structure and copolymer sequence, provided the polyester contains at least one carboxylic acid end group that is ionizable to anions.

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