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.

Formation of cyclic acylphosphoramidates in mass spectra of N-monoalkyloxyphosphoryl amino acids using electrospray ionization tandem mass spectrometry

2010 ◽  
Vol 45 (7) ◽  
pp. 779-787 ◽  
Author(s):  
Xiang Gao ◽  
Feng Ni ◽  
Jian Bao ◽  
Yan Liu ◽  
Zhen Zhang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
Mass Spectra ◽  
Tandem Mass ◽  
Ionization Tandem Mass Spectrometry

Structural Characterization of Nitrated 2′-Hydroxychalcones by Electrospray Ionization Tandem Mass Spectrometry

2009 ◽  
Vol 15 (5) ◽  
pp. 605-616 ◽  
Author(s):  
Ana I.R.N.A. Barros ◽  
Fernando M. Nunes ◽  
Cristina Barros ◽  
Artur M.S. Silva ◽  
M. Rosário M. Domingues
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
Structural Information ◽  
Tandem Mass ◽  
Substitution Pattern ◽  
Esi Ms ◽  
Positive Mode ◽  
Fragmentation Patterns ◽  
Product Ion Spectra

Isomeric 2′-hydroxychalcones bearing nitro and methoxy groups in different positions of their skeleton were analyzed by tandem mass spectrometry (MS/MS) with electrospray ionization (ESI), in positive mode. Collision-induced dissociation of the protonated molecules, [M + H]+, formed under electrospray conditions were studied and it was found that the product ion spectra of these chalcones presented different fragmentation patterns depending on the position of the substituents on the molecule. The product ion spectra (ESI-MS/MS) of the B ring ortho-nitro substituted 2′-hydroxychalcone and of the 4′-methoxychalcones showed loss of OH•, 2OH• and combined losses of OH• and H2O. These fragment ions were absent in the spectra of the respective meta- and para isomers. The observed differences in the product ion spectra of these nitrochalcones allowed identification of the o-nitro derivatives. Distinction between the meta- and para-derivatives was not achieved. Chalcones bearing 6′-methoxy substituents showed distinct fragmentation from the one observed for their isomers, 4′-methoxychalcones, since they present only one fragment ion, a typical (0,αA – H)+ and, therefore, do not allow detailed structural information to be obtained, nor to differentiate between the o-, m- or p-nitro isomers. Overall, it was found that small changes in the substitution pattern of chalcones change their fragmentation considerably in the ESI-MS/MS, and that these features permit the differentiation of specific isomers of these 2′-hydroxynitrochalcones.

ChemInform Abstract: Interpretation of Oligonucleotide Mass Spectra for Determination of Sequence Using Electrospray Ionization and Tandem Mass Spectrometry.

ChemInform ◽  
2010 ◽  
Vol 27 (40) ◽  
pp. no-no
Author(s):  
J. NI ◽  
S. C. POMERANTZ ◽  
J. ROZENSKI ◽  
Y. ZHANG ◽  
J. A. MCCLOSKEY
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Electrospray Ionization ◽  
Mass Spectra ◽  
Abstract Interpretation ◽  
Tandem Mass
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