17. Thermographic analysis of known organic substances

The evaluation of thermograms from Evolved Gas Analysis, EGA, is a common procedure to estimate the amount of organic and black carbon content in urban aerosols. This technique relies on the oxidation process that occurs when a sample is heated in a furnace at controlled temperature as the emitted gases are converted to carbon dioxide. Many thermograms show two main peaks that represent two groups of organics. The first occurs at 200-250°C and is related to volatile compounds with high vapor pressure; and the second peak occurs between 300 and 340°C and is related to semi volatile compounds with lower vapor pressure. It is not well known what type of compounds are included in each group. The objective of this study is to analyze 13 organic substances with the EGA and evaluate the subsequent patterns. The analysis shows that there is a consistent behavior between the thermographic patterns and the number of aromatic rings that make up the compounds.

Keywords: EGA, thermographic analysis, thermographic patterns, carbon content