Size Exclusion Chromatography

Pasch, Harald; Trathnigg, Bernd

doi:10.1007/978-3-642-58265-3_4

Cited by 1 publication

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References 39 publications

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“…M n values determined from the GPC data were consistently the lowest. Several factors must be considered when explaining differences observed for the techniques including the following: (1) accurate quantitation by MS analysis of the low-mass tails of the 10−40 ku samples, (2) accurate integration of the methyl end group region for 1 H NMR analysis, and (3) accurate M n determination biased by end group variation and limited by apparent polystyrene mass calibration for GPC analysis. − Currently, we are investigating an approach to better evaluate uncertainties associated with the three techniques in order to make reliable comparisons.…”

Section: Discussionmentioning

confidence: 99%

Examination of the Covalent Cationization Method Using Narrow Polydisperse Polystyrene

et al. 2005

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Four bromine-and phosphonium-terminated polystyrenes were analyzed by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) using covalent cationization. Bromineterminated polystyrenes were prepared by atom transfer radical polymerization (ATRP) giving narrow molar mass (MM) distributions with number-average molar mass ranging from 2 to 40 ku. The resultant bromine end group was converted to a phosphonium ion. Precharging the polymer by covalent cationization is an alternative approach to traditional metal cationization for MALDI-MS polymer analysis. MALDI-MS, gel permeation chromatography, and proton nuclear magnetic resonance analyses confirmed ATRP synthesis and end group modification of the polystyrenes. High performance liquid chromatography at the critical point of adsorption was used to determine a phosphonium salt conversion between 37% and 90%. Similar MMs and MM distributions determined by MALDI-MS analysis were observed for Brterminated polystyrene ionized using traditional metal cationization and the covalently cationized (i.e., phosphonium-terminated) polystyrene. Covalently cationized samples yielded better data quality than the Br-terminated samples. Higher signal intensity and signal reproducibility were observed for the covalently cationized samples using milder laser conditions.

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