The effect of (NH4)(2)HPO4 and (NH4)(2)SO4 on the composition of the volatile organic pyrolysis products of Pinus halepensis pine-needles

Pyrolysis gas chromatography with flame ionization detector (Py-GC-FID) and pyrolysis gas chromatography with mass selective detector (Py-GC-MSD) were used for studying the effect of (NH4)(2)HPO4 and (NH4)(2)SO4 on the pyroly sis of Pinus halepensis pine-needles. Flash Py-GC-MSD analysis of the pine- needles at 400 degrees C, showed differences in the composition of the orga nic volatile products after treatment with chemicals. The major ones were t he formation of new products such as levoglucosenone due to the alteration of thermal degradation mechanism, or due to the interaction of chemicals wi th the pine-needles pyrolysis products like benzonitrile. Py-GC-FID was app lied to pine-needles in a temperature region of 100-600 degrees C, for moni toring changes regarding the evolution profile of various pyrolysis product s, as well as their pyrolysis temperature shifting in the presence of chemi cals. The Py-GC-MSD and Py-GC-FID proved to be effective and promising meth ods for the elucidation of retardation mechanisms during the pyrolysis of p ine-needles. (C) 1999 Elsevier Science Ltd. All rights reserved.