Pittcon 2020 – Using GCxGC in environmental forensics and forensic litigation matters

Dr. Court D. Sandau and Michelle Misselwitz to present at Pittcon 2020

Dr. Court Sandau will present Using GCxGC in environmental forensics and forensic litigation matters.

Abstract:

Wildfires continue to grow in frequency and intensity. Over 80% of wildfires are human caused, with over 20% being attributed to acts of arson. The ability to detect ignitable liquid residues (ILRs) in wildfire debris samples can be very problematic compared to structural fire debris samples.

Forensic methods used in the analysis of wildfire debris are complicated by the presence of natural interferences. Wildfires provide exceptionally difficult matrices compared to structural fires due to the facts that: ILRs are present at lower concentrations; ILRs are more dispersed; natural compounds are present at very high concentrations; structural similarity of natural compounds to ILR compounds; and matrix combustion forms other interfering compounds.

The resolving power of comprehensive two-dimensional gas chromatography (GCxGC, 2DGC) combined with the sensitivity of a TOF-MS permits superior separation and detection of ILRs compared to conventional gas chromatography (1DGC). The high abundance of natural interferences dwarfs the ILR compounds in size and will mask their detection using conventional 1DGC. As arsonous wildfires can ignite with very low volumes of accelerants, better detection limits are required in order to find and identify ILRs in wildfire debris samples.

Case samples analyzed on both 1DGC and 2DGC showed re-analysis by 2DGC changed 7% of negative samples to positive for ILR, and 22% went from tentative to positive for ILR. Inspection of the Stauffer compounds shows some groups are more useful for ILR identification than others. The Three Musketeers Group was ubiquitous, while the Twin Towers and Five Fingers Groups were non-detects by 1DGC but present in up to 90% of positive samples by 2DGC.  In addition, the use of 2DGC allows expansion of the targeted list of compounds to expand to all compounds present in gasoline which increase to over 2000 compounds, potentially allowing for gasoline fingerprinting.

Michelle Misselwitz of Chemistry Matters will be leading the Beginners Guide to Comprehensive Two-Dimensional Gas Chromatography (GCxGC). 

There is an outstanding need to educate and inform the broad analytical community about comprehensive two-dimensional gas chromatography (GC×GC). GC×GC has continued to grow and diversify with regular appearances in most major conferences. After completion of this course attendees will be familiar with the benefits and operation of GC×GC and determine when it is an appropriate technique for their laboratory. Attendees will be able to compare and contrast different GC×GC systems, identify resources for method development, and formulate strategies for coping with GC×GC data. A diverse collaboration of scientists will instruct this
course to provide attendees with a well-rounded GC×GC educational experience.
COURSE OUTLINE
1. Introduction
    a. Benefits of GC×GC compared to 1D GC
    b. Hot topics and application examples
    c. Fundamentals of GC×GC
    d. History, key papers and references
    e. Modulator types and considerations
2. Method Development
    a. Column selection
    b. Temperature and flow parameters
    c. Detector options and requirements
    d. Optimization and troubleshooting
3. Hands-on Demonstrations
    a. On-site GC×GC instrument
    b. Column connections and installation
    c. Online resources
4. Data Analysis
    a. System requirements and options
    b. Data processing parameters
    c. Data reduction strategies
    d. Quantitative and Qualitative analysis
    e. Statistical approaches
5. Applications of GC×GC
    a. Petroleum
    b. Environmental
    c. Forensics
    d. Food Safety
    e. Metabolomics

GCMS vs. GCxGC