Interpreting comprehensive two-dimensional gas chromatography using peak topography maps with application to...

Area of Science:

• Analytical Chemistry
• Geochemistry

Background:

• Comprehensive two-dimensional gas chromatography (GC×GC) offers high-resolution separation of complex mixtures.
• GC×GC topography provides rich data for quantitative interpretation, particularly in petroleum forensics.
• Biomarker hydrocarbons like hopanes and steranes are crucial for weathering-resistant petroleum analysis.

Purpose of the Study:

• To develop a quantitative compound-cognizant interpretation framework for GC×GC topography.
• To apply this framework to petroleum forensics, moving beyond traditional target compound analysis.
• To introduce Peak Topography Maps (PTM) for enhanced biomarker analysis.

Main Methods:

• Utilizing GC×GC topography of biomarker hydrocarbons (hopanes and steranes).
• Introducing Peak Topography Maps (PTM) and topography partitioning techniques.
• Analyzing a broader range of 33-154 target and non-target biomarkers.
• Developing a quantitative measure for direct sample "match" determination without training data.

Main Results:

• Validated methods across 34 GC×GC injections from diverse petroleum sources.
• Demonstrated statistically significant sample matching using PTM for Deepwater Horizon disaster samples.
• Showcased PTM's superior differentiation of closely correlated sources compared to Principal Components Analysis (PCA).
• Confirmed PTM robustness through numerical simulations with peak location variability.

Conclusions:

• A peak-cognizant informational framework for GC×GC topography interpretation is presented.
• Topographic analysis facilitates GC×GC forensic interpretation of petroleum biomarkers, including non-target compounds.
• This approach enables the discovery of novel connections between target and non-target biomarkers.