Evolved gas analysis (EGA) was carried out on 15 synthetic polymer samples using z temperature programmable pyrolyzer as a heating unit which was on-line coupled with z MS detector. A deactivated stainless steel tube and a vent free adapter were used to couple the pyrolyzer with the MS detector, and they were placed in a GC oven at 300 degrees C to avoic condensation of evolved gases with high boiling point. Thermograms of polystyrenE measured by this system (Py-EGA-MS) showed shifts of the peak temperature to the higher temperature region as the sample mass increased. It was found that the S/N ratio: of EGA thermograms were 420-fold superior to those of differential thermogravimetr) (DTG) thermograms for the same sample mass of 0.20 mg. Since a good linear relationship was obtained between peak temperatures obtained by Py-EGA-MS and DTG, it can bE concluded that Py-EGA-MS can be used to obtain reliable data on thermal properties o samples with high sensitivity and using less sample.(C) 2015 Elsevier Ltd. All rights reserved