Polymer analysis tandem mass spectrometry

LSIMS is a more suitable ionisation technique than FD for analysis of mixtures by means of tandem mass spectrometry, because of the higher ion currents generated from polymer additives using LSIMS. LSIMS/MS experiments may be used in conjunction with FD-MS as a screen to determine class, molecular weight and structure of mixtures of organic polymer additives. 

If we consider only a few of the general requirements for the ideal polymer/additive analysis techniques (e.g. no matrix interferences, quantitative), then it is obvious that the choice is much restricted. Elements of the ideal method might include LD and MS, with reference to CRMs. Laser desorption and REMPI-MS are moving closest to direct selective sampling tandem mass spectrometry is supreme in identification. Direct-probe MS may yield accurate masses and concentrations of the components contained in the polymeric material. Selective sample preparation, efficient separation, selective detection, mass spectrometry and chemometric deconvolution techniques are complementary rather than competitive techniques. For elemental analysis, LA-ICP-ToFMS scores high. 

An ultrapure polymer is made of chains of the type G1-AAAAAAA-G2, where A is the repeat unit and G1 and G2 are end-groups. One considers the mass number of one of the MS peaks, subtracts the mass of the cation (e.g., H, Li, Na, Ag), and then repeatedly subtracts the mass of the repeat unit, until one obtains the sum of the masses of G1 + G2. For this purpose, a linear best fit can also be used. Tandem mass spectrometry is particularly useful since, from the analysis of ion fragmentation patterns, one can deduce the mass of G1 and, separately, the mass of G2. 

Chan, J.H., Timperman, A.T., Qin, D., Aebersold, R., Microfabricated polymer devices for automated sample delivery of peptides for analysis by electrospray ionization tandem mass spectrometry. Anal. Chem. 1999, 71, 4437 1444. 

Tandem Mass Spectrometry Tandem MS is an early technique that involves the isolation of a specific ion followed by its fragmentation, which occurs in a collision cell, resulting in a fragment ion spectrum. This technique has been satisfactorily used for the smdy of peptide sequences [41], but it can also be used for the analysis of synthetic polymers. 

Jackson, A. T., Jennings, K. R., and Scrivens, J. H., Analysis of a fivepolymer additives by means of high energy mass spectrometry and tandem mass spectrometry. Rapid Commun. Mass Spectrom., 10,1449, 1996. Lattimer, R. P., Layer, R. W., and Rhee, C. K., Mechanisms of antiozonant protection Antiozonant-rubber reactions during ozone exposure. Rubber Chem. Technol, 57, 1023, 1984. 

Hilton, G.R. Jackson, A.T. Thalassinos, K. Sciivens, J.H. Structural analysis of synthetic polymer mixtures using ion mobility and tandem mass spectrometry. Anal. Chem. 2008, 80, 9720-9725. 

Yalcin, T., Gabryelski, W, Li, L. (2000) Structural analysis of polymer end groups by electrospray ionization high-energy collision-induced dissociation tandem mass spectrometry. Anal. Chem., 72(16), 3847-3852. 

Unambiguous determination of monomer sequence in copolymers 3 is a requisite for evaluation of various synthetic approaches in controlling their microstructure. Knowledge of microstructure, especially monomer sequence information, is vital to detailed understanding of structure-property relationships. All well established spectroscopic methods, e.g. IR, UV-VIS, and NMR, are severely limited by the structural similarity of these monomers. All contain the N-alkyl-4-vinylpyridinium chromophone. A new method for sequencing synthetic polymers based on pyrolysis/tandem mass spectrometry has been developed by Cooks and associates [66] and applied to analysis of copolymer 3. Desorption chemical ionization (DCI) and desorption electron... 

The mass spectra of mixtures are often too complex to be interpreted unambiguously, thus favouring the separation of the components of mixtures before examination by mass spectrometry. Nevertheless, direct polymer/additive mixture analysis has been reported [22,23], which is greatly aided by tandem MS. Coupling of mass spectrometry and a flowing liquid stream involves vaporisation and solvent stripping before introduction of the solute into an ion source for gas-phase ionisation (Section 1.33.2). Widespread LC-MS interfaces are thermospray (TSP), continuous-flow fast atom bombardment (CF-FAB), electrospray (ESP), etc. Also, supercritical fluids have been linked to mass spectrometry (SFE-MS, SFC-MS). A mass spectrometer may have more than one inlet (total inlet systems). 

Direct polymer compound analysis by soft ionisation, tandem MS/MS and high-resolution (AC-MS) mass spectrometry, has been reviewed [236]. 

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