Curie-point pyrolysis mass spectrometry, Curie-point pyrolysis-gas chromatography-mass spectrometry and fluorescence microscopy as analytical tools for the characterization of two uncommon lignites

Abstract

A case study is presented of two uncommon lignite samples, PSOC-975 and PSOC-427, which were studied by microscopic and analytical pyrolysis methods. Pyrolysis-mass spectrometric (Py-MS), pyrolysis-gas chromatographic (Py-GC) and Py-GC-MS data demonstrate that lignite PSOC-975 contains a high abundance of resinous material of some sort, whereas PSOC-427 is characterized by two major unknown pyrolysis products, prist-1-ene and alkylphenols. The chemical data contradict the microscopic observations, which point to a maceral composition of woody and cortical tissues, although a considerable part is unrecognizable. Apparent discrepancies between low-voltage Py-MS and 80-eV Py-GC-MS results were evaluated by a study of standards. It was shown that the aliphatic hydrocarbons are highly underestimated in low-voltage Py-MS. The nature of the disagreement observed between maceral composition and the pyrolysis data needs further study.