Mixtures of cyclic oligomers of poly(lactic acid) analyzed by negative chemical lonization and thermospray mass spectrometry.

An investigation of the distribution of the cyclic oligomers of poly(lactic acid), formed both by pyrolysis of the polymer and by equilibration with a catalyst, has been performed by Negative Chemical Ionization and Thermospray Mass Spectrometry. The results indicate that the two methods can be used to obtain information on the relative amounts of the oligomers present in the mixture. [ABSTRACT FROM AUTHOR]