Quantitative determination of hydrocarbons by structural group-type via high-performance liquid chromatography with dielectric constant detection

A dielectric constant (DC) detector for high-performance liquid chromatography (HPLC) is the basis of an accurate and versatile hydrocarbon group-type analysis. The method can determine saturates (+ olefins), alkylbenzenes, and polynuclear aromatics in hydrocarbon liquids boiling below 600/sup 0/C. The HPLC separation is achieved with three columns in series, i.e., two (2) 5-..mu..m Partisil PAC columns preceding a 10-..mu..m 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% relative standard deviation) for each hydrocarbon group type independent of the carbon-number distribution of the sample. On the basis of 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). 16 references, 4 figures, 7 tables.