Characterisation of Forgotten Pollutants & Resolving the UCM Using Pegasus 4D CF GC×GC-TOFMS

S.J. Rowland1, A. Scarlett1, C.E. West1, Sjaak De Koning2 and Sonja Hofmeister2


Petroleum and Environmental Geochemistry Group, The University of Plymouth, U.K.
2 Separation Science, LECO European Technical Centre (ETC), Mönchengladbach, Germany

Presented at: 34th International Symposium on Capilary Chromatography and 7th GC×GC Symposium,
Riva del Garda, Italy, 30 May-4 June 2010.

Download: Poster as an A4 pdf file.

Brief Summary

Due to the growing requirement for analysis of highly complex samples of organic compounds, often in difficult matrices, there are huge demands on instrumentation and the capabilities of software to interpret the resulting data. Good examples of the highly complex nature of pollutant organics are the socalled unresolved complex mixtures (UCMs) of hydrocarbons, acids and other chemicals occurring in crude oils. The objective of the current project was to use comprehensive two-dimensional gas chromatography (GC×GC) to try to resolve UCMs of petroleum hydrocarbons and acids- typical of those occurring in environmental samples such as sediments.

By capitalising on the ability of GC×GC to chromatographically resolve thousands of individual chemical components from the UCMs, the sources, weathering, and toxicity of UCM components can be better understood. This research has important consequences for petroleum industrial activities as well as for pollution studies as there is significant and increased toxicity of UCMs of aliphatic hydrocarbons once they become oxidized to acids.

The LECO Pegasus 4D GC×GC-TOFMS shows how previously unresolved UCMs can be chromatographically resolved using a dual stage thermally modulated GC×GC separation with full mass range spectra collected. The resulting raw data were automatically processed using ChromaTOF® software with True Signal Deconvolution (TSD®). Data here are displayed in three dimensional chromatographic images to aid understanding and explanation.

Samples "NA-mix" (methyl esters of a sample of commercial naphthenic acids) and "Silk" (the hydrocarbon feedstock of a lubricating oil) were analysed, demonstrating the capability of the LECO Pegasus 4D GC×GC-TOFMS instrument to address the analytical challenge that a UCM presents to researchers and industrialists alike.

Download the complete poster as an A4 pdf file.

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