Jet fuels typically consist of simple blends of different kerosene streams – such as straight run kerosene from the crude tower, hydrotreated kerosene and hydrocracked kerosene.[1] Kerosene is known as a middle distillate, typically in the range of C9 to C16 hydrocarbons, but the precise composition will be dependent on the original crude oil from which it was derived.
Fuels, like kerosene, are among the most complex of samples to be analysed by gas chromatography, typically containing thousands of individual components that result in an unresolved hump in a 1D GC chromatogram. Therefore, their analysis is now typically performed by two-dimensional GC (or GC×GC) for enhanced separation in a realistic run time.
However, in petrochemical analyses, it is not necessary nor even possible to identify every individual component – rather, the responses for key chemical classes are summed, in what is known as group-type analysis. Most commonly, this follows ‘PiPNA’ classification, whereby the Paraffins, iso-Paraffins, Naphthenes and Aromatics are reported and other compound classes, like olefins, are either known or assumed to be unrepresented in the sample.
