Suitability of thin-layer chromatography-flame ionization detection with regard to quantitative characterization of different fossil fuel products. I. FID performances and response of pure compounds related to fossil fuel products

Controversy exists concerning quantitation using thin-layer chromatography-flame ionization detection (TLC-FID). Inadequate sample selections and detector designs and the non-uniformity of chromarods have been blamed for some confusing results. In this paper, performances of a modern TLC-FID system (which includes the newest detector configuration) are tested on polycyclic aromatic compound standards and related compounds as a preliminary step to evaluate its suitability for quantitative hydrocarbon group type analysis of different coal and petroleum products. Thus, evaluation of performances of the most modern FID configuration is carried out. FID linearity is evaluated as a function of sample load and scan speed for high-molecular-weight and semi-volatile standards. TLC-FID response factors for compounds of several homologous series are studied in order to differentiate effects of volatility from those exclusively due to chemical nature concerning FID response. Therefore, criteria are developed for the accurate application of TLC-FID to fossil fuel samples. Measurements of chromarod temperatures are carried out in order to evaluate whether an evaporation of compounds outside the H2 flame might take place.