IDENTIFICATION OF POLY(ETHYLENE-TEREPHTHALATE) CYCLIC OLIGOMERS BY LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY

Plasmaspray liquid chromatography-mass spectrometry has been used to detect and identify cyclic oligomers, (GTBAR)n, in samples of poly(ethylene terephthalate). Operating the mass spectrometer at unusually high temperatures (370-degrees-C for the tip), the identity of the two main peaks, which were attributed to (GTBAR)3 and (GTBAR)4 on the basis of their UV absorption, could be confirmed by the m/z value of their molecular anions. The very poor results observed at lower temperatures exemplify the difficulty of vaporizing and ionizing these molecules.