Characterization of low molecular weight polymers by matrix-assisted laser desorption/ionization mass spectrometry. A comparison with gel permeation chromatography

Abstract

A series of low molecular weight surfactants with narrow molecular weight (MW) distribution (MW ranging from 860 to 5310 Da), containing poly(oxyethylene oxide) and the acylal (double ester and carbonate ester) functional group, was prepared as potential candidates for drug delivery vehicles. Determination of molecular weight of the polymers was done by both Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and gel permeation chromatography (GPC) equipped with viscosity detector. The former technique offered a far more convenient method of characterization of these polymers than GPC. The major advantages were lack of requirement for a chromatographic separation system, short time for sample preparation, speed of analysis, and structure information (repeating unit) of the polymers. For the lower MW species studied the MS data were closer to theoretical values than the GPC data. For the polymers having theoretical MW ≈ 5000 Da, the deviation between GPC data and MS data was less pronounced. © 1998 John Wiley & Sons, Ltd.