Molecular Mass Characteristics of (2-Benzothiazolon-3-yl)acetic Acid-Telechelic Poly(ethylene oxide)s Determined by MALDI-TOF Mass Spectrometry and SEC

Abstract

(2-benzothiazolon-3-yl)acetic acid–telechelic poly(ethylene oxide)s (1 100–4 440 Da) with narrow molecular mass distributions (MMD) were analysed by matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and size exclusion chromatography (SEC). The average molecular masses (M̄n and M̄w) determined by both methods were compared and a good agreement established. The cutting of the low molecular part of the initial poly(ethylene glycol) MMD during purification and isolation of the produced telechelic poly(ethylene oxide)s was proved. For this reason, the degree of esterification (x) of poly(ethylene glycol) (PEG) with (2-benzothiazolon-3-yl)acetic acid was calculated by MALDI-TOF MS and SEC, using additional UV data. The two series of x values derived from the M̄n-values, determined by the two methods, are very close. All of them are less than unity and the differences between the two types of x values decrease with the PEG molecular mass growth.