Complete Group-Type Quantification of Petroleum Middle Distillates Based on Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry (GC×GC-TOFMS) and Visual Basic Scripting

The
subject of the presented work was the development of a two-dimensional
GC×GC–time-of-flight
mass spectrometric method (GC×GC-TOFMS) for the complete group-type
quantification
of petroleum middle distillates. The development of this method was
possible due to the inherent features of GC×GC-TOFMS, namely
the structured arrangement of
compound groups and the mass fragmentation pattern, which provide
the possibility of using Visual Basic Scripts as an analytical tool
and thereby the classification of several thousand different compounds.
The analysis method was focused on common petroleum based fuels from
light to heavier middle distillation fractions. For the implementation
of an absolute quantification method, a set of standard substances
representing the main substance classes and carbon numbers within
middle distillates and well-separated and recognizable internal standards
were thoroughly chosen in order to obtain individual response factors
and group specific response curves. The results of the qualitative
and quantitative analysis were compared to well-established standard
methods used in the petrochemical industry. The quantification of
aromatic hydrocarbons was compared to EN 12916, a high performance
liquid chromatography (HPLC) method that provides a rough separation
between mono-, di-, and higher aromatics. Further, the quantification
of the fatty acid methyl ester (FAME) content in diesel fuel was compared
to EN 14078 and the distribution of single FAMEs was compared to EN
14103. It could be stated that an absolute quantification as the here
presented method has not been reported before and the results were
in good agreement with the reference methods. Furthermore, the here
presented GC×GC-TOFMS quantification method is able to itemize
according substance classes
and carbon number. The detection limit of the method allows accurate
and sensitive quantification for different limiting values of middle
distillates with a single method.