ANALYSIS OF POLAR AND NON POLAR SYNTHETIC POLYMERS AND DENDRIMERS BY LASER DESORPTION MASS SPECTROMETRY

摘要

Dkect and specific means of analysis of polymers is a long-sought goal of polymer chemists. Because of polymer non:volatility, mass spec-trometry has not been a traditional method for such analyses. However, the advent of laser desorption mass spectrometry offers improved prospects for mass spectrometric analysis of such mixtures. Of course, it is essential to determine to what extent mass discrimination is a problem and to develop means to circumvent this difficulty, if it exists. Montaudo and co-workers recently reported matrix-assisted laser desorption time-of-flight (MALDI-TOF) results for analysis of a number of poly(methylmethacrylate), poly(ethyleneglycol), and poly(styrene) polymer samples with various molecular weight distributions1. These investigators found that mass discrimination becomes significant when the polydispersity index exceeds a value of about 1.10. We have observed that when poly(ethyleneglycol) polymer mixtures with large polydispersity are analyzed by MALDI, but using a Fourier transform mass spectromcter(FTMS) for mass analysis, substantial mass discrimination occurs2. In this case, choice of gated trapping potential delay is the cause.