DETERMINATION OF HYDROCARBON TYPES IN GASOLINE RANGE SAMPLES BY MULTIDIMENSIONAL GAS-CHROMATOGRAPHY, FLUORESCENT INDICATOR ADSORPTION AND BROMINE NUMBER METHODS

The hydrocarbon type analysis of light naphthas, alkylates and reformates was carried out by multidimensional gas chromatography (MD-g.c.) using a mode which provided the amounts and carbon number distributions of paraffins, olefins, naphthenes and aromatics (PONA) in each sample. The MD-g.c. results were compared with the total saturates, olefins and aromatics obtained by the ASTM method D 1319, which utilizes open column chromatography coupled with fluorescent indicator adsorption (FIA). The olefin contents obtained by MD-g.c. were correlated with bromine number results obtained by the ASTM method D 1159. It was found that both the type of information and precision of results from MD-g.c. are superior to those obtained by the FIA and bromine number methods. Moreover, the MD-g.c. method is free from limitations that affect results obtained by the other two methods. Some systematic bias in the FIA and bromine number results was observed and the possible sources were identified.