Analysis of ethoxylated polymers by capillary electrophoresis in UV-transparent polymer networks and by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

This report describes the application of capillary electrophoresis (CE) in UV-transparent polymer solutions to the separation of poly(ethylene glycol)s and ethoxylated surfactants. Polymer networks of dextran and polyethylene oxide provide size selectivity in these separations. These ethoxylates were derivatized prior to CE analysis with 1,2,4-benzenetricarboxylic anhydride (BTA) to impart charge and detectability on the neutral polymer. The utilization of a polymer network with low UV absorbtion at 210 nm permits the detection of the ethoxylates with high sensitivity at this wavelength. Migration time was found to be linearly dependent on analyte molecular mass. The results obtained by capillary electrophoresis (CE) are compared with those obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and the off-line coupling of these techniques is described. (C) 1998 Elsevier Science B.V.