On-line Curie-point pyrolysis-high-performance liquid chromatographic-mass spectrometric analysis of lignin polymers

An on-line Curie-point pyrolysis (Py)-HPLC-MS system has been developed for the analysis of oligomeric and polar compounds which are present in pyrolysis tars. The pyrolysis unit used was designed in such a way that inductive heating of the ferromagnetic sample probe and subsequent trapping of the pyrolysis products is performed inside a glass column, which is part of the analytical system. Cold-trapped compounds are solubilized, concentrated on a precolumn and subsequently separated with conventional RP-HPLC by use of column switching. A frit-electron impact ionization/chemical ionization interface and a continuous flow frit-fast atom bombardment interface are used to couple the chromatographic system directly to a double focusing mass spectrometer. In this study the method is presented, optimized and evaluated for lignin polymers. Results are compared with in-source Py-MS and Curie-point PY-GC-MS data. The first results, presented in this study, clearly demonstrate the feasibility and potential of Py-LC-MS as a reproducible and rapid screening method for the analysis of isomeric and oligomeric structures produced upon pyrolysis of insoluble polymers.