Quantitative Determination of Hydrocarbon Group-Types via High Performance Liquid Chromatography with Dielectric Constant Detection

摘要

A dielectric constant (DC) detector for high performance liquid chromatography (HPLC) is the basis of an accurate and versatile hydrocarbon group-type analysis of petroleum-and shale-derived distillate fuels. The method can saturates (+ olefins), alkyl benzenes, and polycyclic aromatics in hydrocarbon liquids below 600 C. The HPLC separation is achieved with three columns in series, i.e., two (2) five micrometer Partisil PAC columns preceding a ten micrometer TENF column, and using n-butyl chloride as the mobile phase. A simple three-component standard mixture is all that is required to calibrate the method. The DC detector ensures a genuine uniformity of response (less than 2.5% RSD) for each hydrocarbon group-type independent of the carbon-number distribution of the sample. Based on simple and complex hydrocarbon standard solutions, the accuracy for each structural group-type is within 2% absolute with a chromatographic limit of detection of approximately 150 ng for a late eluting solute (biphenyl).