3767028 Py-GC-MS pyrolysis-gas chromatography-mass spectrometry 161 3767035 Py-GC-MS pyrolysis-GC-MS 8 3767033 Py-GC-MS pyrolysis gas chromatography 2 3767034 Py-GC-MS polyethylene in an analytical micropyrolyzer coupled to GC-MS 1 3767032 Py-GC-MS pyrolysis gas chromatography high resolution mass spectrometry 1 3767036 Py-GC-MS pyrolysis-gas chromatography-mass 1 3767030 Py-GC-MS Pyrolysis-Gas Chromatography-Mass Spectrometry analysis 1