THIOPHENIC SULFUR DISTRIBUTION IN PETROLEUM FRACTIONS BY GAS-CHROMATOGRAPHY WITH A FLAME PHOTOMETRIC DETECTOR

The flame photometric detector (FPD), introduced ten years ago, has gained widespread acceptance as a sensitive and specific detector for sulfur compounds. Although it has been applied as a sulfur specific detector for a wide variety of compounds, its use in cases of mixtures has been as a qualitative tool. For quantitative work, the FPD has largely been limited to trace (ppm and ppb) sulfur gases in air and higher levels of pesticides in various formulations. It Is the purpose of this paper to illustrate how the FPD can be used for quantitative determination of a specific class of sulfur compounds, namely, thiophenes. The response of the sulfur FPD is a power function of the sulfur concentration. Because the response, hence the exponent, varies with the class of sulfur compounds, the mixtures of sulfur compounds in the petroleum fractions are first separated into nonthiophenes (largely mercaptans and sulfides) and thiophenes by a catalytic procedure. The thiophene mixture is then used for the analysis described. © 1979, Oxford University Press. All rights reserved.