Detection, Identification, and Quantification of Nonpolar High Molecular Weight Contaminants in Jet and Diesel Fuels by Liquid Chromatography

Abstract

A straightforward analytical methodology has been developed for the identification and characterization of nonpolar high molecular weight contaminants, such as lubricant oils and greases, in jet and diesel fuels. Such contaminants typically contain a distribution of compounds with carbon numbers in the range C25–C40, or 350–600 Da, which are sufficiently larger than fuel constituents to be effectively detected via liquid chromatography. The methodology is based on high performance liquid chromatography, utilizing a xylenes–cyclohexane mobile phase gradient to separate these contaminants from fuels by means of dual porous graphite stationary phase columns and evaporative light scattering detection. The limits of detection for n-pentacosane, n-triacontane, n-pentatriacontane, and n-tetracontane were determined to be approximately 0.1 ppm, with an upper limit of 10% by volume. The newly developed methodology improves upon a previously developed methodology by both enhancing the resolution of high molecular w...