Gel permeation chromatography followed by pyrolysis–gas chromatography–mass spectrometry via a solvent-evaporative interface

The measurement of chemical composition as a function of molecular weight has always been a challenge for analytical chemists. In this paper, we present a unique way to combine gel permeation chromatography (GPC) with pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) for this purpose. A commercially available solvent-evaporative interface, originally designed for GPC–IR measurements, was used to deposit the eluent of GPC onto aluminum foil. Small strips of aluminum foil were cut and subjected to Py–GC–MS analysis. Compared with the GPC–IR measurements, the proposed technique offers the advantage of being able to distinguish between structurally similar monomers in a complex copolymer. As an example, a copolymer composed of four monomers was analyzed. The results clearly demonstrate that this technique can be applied to complex polymeric systems to yield information regarding chemical heterogeneity versus molecular weight.