Wasson Chromatography Corner 17

Significance of the Topic

Efficient monitoring of volatile organic compounds in consumer aerosols and impurities in fuel gases is critical for environmental compliance, health safety, and process optimization. Additionally, advanced detectors like PDHID expand sensitivity for trace analysis, addressing stringent regulatory requirements and improving analytical performance.

Objectives and Overview of the Studies

• Quantify the composition of consumer aerosol propellants to ensure regulatory compliance for VOC emissions.
• Identify and measure trace impurities in coal and biomass-derived fuel gases, including sulfur and aromatic species.
• Optimize detector performance with the pulse discharge helium ionization detector for low-level analyses.

Methodology

Gas chromatography was employed across all applications with tailored detectors and sampling techniques:

• Consumer aerosol sampling used Tedlar™ bags with an automated 16-channel sampler connected to a GC-TCD system for hydrocarbons and refrigerants.
• Coal and biomass fuel gas analysis combined GC with MSD, FID, and sulfur chemiluminescence detector, utilizing Deans switching to backflush heavy compounds and separate analyte streams.
• Detector optimization for PDHID focused on maintaining ultra-high purity helium, use of stainless steel or glass flow paths, and avoidance of polymeric materials in gas lines.

Used Instrumentation

• Agilent gas chromatograph with thermal conductivity detector (TCD) for VOC and refrigerant analysis.
• Wasson-ECE Tedlar™ Bag AutoSampler for multi-point bag sampling.
• Agilent GC coupled with inert MSD, flame ionization detector (FID), and sulfur chemiluminescence detector (SCD).
• Pulse discharge helium ionization detector (PDHID) with high-purity helium purifier and stainless steel flow components.

Main Results and Discussion

Consumer aerosol analysis achieved quantification of major propellant components such as nitrogen, CO₂, HFC-134a, HFC-152a, propane, and butane isomers. The Tedlar™ bag sampling ensured reproducible results and enabled high throughput.

Fuel gas profiling detected C₂–C₄ paraffins and olefins at sub-ppm levels, and identified trace aromatic hydrocarbons like benzene, toluene, and naphthalene. Sulfur species including H₂S, COS, thiols, and benzothiophene were quantified down to 10 ppb.

PDHID performance demonstrated low single-digit ppb detection limits for a broad range of organic compounds, with background reduction strategies improving baseline stability below 2000 pA.

Benefits and Practical Applications

• Ensures compliance with VOC emission regulations in consumer products.
• Provides comprehensive impurity profiling in fuel gases for quality control and process monitoring.
• Enhances sensitivity and reproducibility in trace organic analysis through PDHID optimization.
• Automated sampling solutions increase lab throughput and reduce manual errors.

Future Trends and Applications

Integration of multi-detector GC systems with automated sampling will expand capabilities for real-time monitoring in field and industrial environments. Advances in ionization technologies and column materials are expected to lower detection limits further and broaden analyte coverage. Coupling GC-MS with data analytics and machine learning will improve compound identification and quantitation in complex matrices.

Conclusion

The combined approaches detailed in the studies demonstrate robust strategies for sensitive, accurate analysis of volatile and trace organic compounds across consumer and energy sectors. Instrumentation innovations and methodological refinements support regulatory compliance, environmental protection, and industrial quality assurance.

References

No external references were cited in the original newsletter.