Advanced Forensic Fuel Fingerprinting Using Comprehensive Two-Dimensional Gas Chromatography with Flame Ionization Detection (GCxGC-FID)Environmental Forensics
Oral Presentation
Prepared by E. Litman1, J. Binkley2, B. Nelson3, C. Reddy4, K. DeMille1
1 - NewFields Environmental Forensics, 300 Ledgewood Place, Suite 205, Rockland, MA, 02370, United States
2 - LECO Corporation, 3000 Lakeview Avenue , St Joseph, Michigan, 49085, United States
3 - Woods Hole Oceanographic Institute, 266 Woods Hole Rd, Woods Hole, MA, 02543-1050, United States
4 - Woods Hole Oceanographic Institute, , ,
Contact Information: [email protected]; 781-424-5731
ABSTRACT
The field of environmental forensic chemistry continues to evolve and expand with advances in analytical technologies. Petroleum fingerprinting using modified SW-846 methods has traditionally been performed using 1-Dimensional (1D) Gas Chromatography (GC). These traditional techniques have proven useful in separating complex mixtures of hydrocarbons by carbon range and boiling point, allowing forensic chemists to characterize and differentiate fuel types. However, 1D GC is unable to separate chemicals by polarity or degree of unsaturation resulting in unresolvable coelutions of chemicals with similar molecular weights. Advances in Comprehensive two-dimensional gas chromatography (GCxGC) provide forensic chemists with a new tool to unravel complex mixtures of hydrocarbons through the simultaneous separation of chemicals by molecular weight or boiling point in the first dimension, and by polarity or degree of unsaturation in the second dimension. This presentation will share a GCxGC approach for forensic petroleum fingerprinting that demonstrates the utility of separating hydrocarbons into non-polar, and polar/unsaturated fractions. The presentation will include a series of petroleum distillate fuel fingerprints that have been separated into aliphatic and aromatic fractions using open column silica-gel chromatography and then analyzed via GCxGC. Comparing the results of aliphatic and aromatic fractions to whole extracts provides a clear demonstration of how GCxGC analysis resolves these classes of chemicals chromatographically. The presentation will offer insights into unique compositional features resolved using GCxGC, new metrics in evaluating environmental weathering, and data analysis techniques for measuring non-polar and polar fractions. The presentation will include legacy petroleum distillate fuels like gasoline, diesel fuel and jet fuel and modern biofuels like biodiesel and renewable diesel.
