Rapid polymer identification by in-source direct pyrolysis mass spectrometry and library searching techniques

In-source direct pyrolysis mass spectrometry is studied for rapid identification of polymers in industrial products. In this technique, polymers are pyrolyzed within the ion source of a mass spectrometer by a coiled filament designed for desorption chemical ionization/desorption electron ionization applications. Pyrolysis products are ionized by 70 eV electron impact, yielding highly reproducible mass spectra characteristic of the polymer composition. Using this technique and a commercial library editor, a comprehensive mass spectral library containing more than 150 polymer entries was developed. The impacts of experimental and polymer variables on the reproducibility of polymer mass spectra were evaluated, The technique was successfully applied to the analysis of polymers in industrial products, showing advantages of short analysis time, high confidence level, and low matrix interference, This study suggests that a robust standard polymer library, independent of laboratory and mass spectrometer type, may be developed. However, more rigorous interlaboratory tests are needed to achieve this goal.