Detailed study of polystyrene solubility using pyrolysis–gas chromatography–mass spectrometry and combination with size-exclusion chromatography

Measuring polymer solubility accurately and precisely is challenging. This is especially true at unfavourable solvent compositions, when only very small amounts of polymer dissolve. In this paper, pyrolysis–gas chromatography–mass spectrometry (Py-GC-MS) is demonstrated to be much more informative and sensitive than conventional methods, such as ultraviolet spectroscopy. By using a programmed-temperature-vapourisation injector as the pyrolysis chamber, we demonstrate that Py-GC-MS can cover up to five orders of magnitude in dissolved polymer concentrations. For polystyrene, a detection limit of 1 ng mL−1 is attained. Dissolution in poor solvents is demonstrated to be discriminating in terms of the analyte molecular weight. Py-GC-MS additionally can yield information on polymer composition (e.g. in case of copolymers). In combination with size-exclusion chromatography, Py-GC-MS allows us to estimate the molecular weight distributions of minute amounts of a dissolved polymer and variations therein as a function of time.