Thermogravimetry-Synchronized, Reference-Free Quantitative Mass Spectrometry for Accurate Compositional Analysis of Polymer Systems Without Prior Knowledge of Constituents

Compositional analysis (CA)—identification and quantification of the system constituents—is the most fundamental and decisive approach to investigate the system of interest. Pyrolysis mass spectrometry (MS) with high resolution over 10,000 is very effective for chemical identification and directly applicable to polymer materials regardless of their solubilities; however, it is less helpful for quantification especially when the references, i.e., pure constituents, are unknown, non-isolable and thus unpreparable. To compensate this weakness, herein we propose reference-free quantitative mass spectrometry (RQMS) with enhanced quantification accuracy assisted by synchronized thermogravimetry (TG). The key to success lies in correlating the instantaneous weight loss from TG with MS signal, enabling the quantitative evaluation of the distinct ionization efficiency for each fragment individually. The determined ionization efficiencies allow conversion of MS signal intensities of pyrolyzed fragments into weight abundances. In a benchmark test using ternary polymer systems, this new framework named TG-RQMS demonstrates accurate CA within ±1.3 wt% errors without using any knowledge nor spectra of the references. This simple yet accurate and versatile CA method would be an invaluable tool to investigate polymer materials whose composition is hardly accessible via other analytical methods.