Wasson Chromatography Corner 12

Significance of the Topic

Gas chromatography remains a cornerstone of industrial and environmental analysis, offering precise, rapid quantification of gaseous and volatile compounds. Customized multi‐detector GC configurations extend analytical capabilities to complex mixtures such as refinery off‐gases and fuel cell reactor effluents, where trace components and real‐time monitoring are critical for process control, safety and regulatory compliance.

Objectives and Study Overview

This newsletter issue presents two case studies of specialized GC systems developed by Wasson‐ECE for the analysis of (1) refinery gas and liquid mixtures using dual thermal conductivity detectors (TCD/TCD) coupled with a mass selective detector (MSD), and (2) fuel cell reactor effluent gas using two synchronized GC instruments. It also includes practical tips for gas chromatography best practices.

Methodology and Instrumentation

In the refinery gas application, an Agilent GC was fitted with two TCDs and an MSD. Light gases (CO₂, H₂, CH₄, C₂ compounds, H₂S, N₂, CO and Ar/O₂ blend) were quantified on two TCD channels down to 10–400 ppm, while formaldehyde, methanol and water were separated by polarity and detected by extracting characteristic ions (m/z 29, 31, 18) on the MSD. Analysis time was ~20 minutes. In the fuel cell effluent study, dual GCs were configured on a single sample loop delivering four simultaneous aliquots. GC A (TCD/TCD/FID) monitored refinery‐type gas species (C₁–C₄ and H₂S), and GC B (FID/FPD) quantified C₅–C₂₀ n-paraffins and H₂S down to 50 ppm in a simulated distillation mode. High‐temperature sample handling (350 °C) required inline wax traps to protect flow controls.

Instrumentation

• Agilent gas chromatograph with dual TCD and MSD detectors
• Gas sampling valve and syringe injection system
• Dual GC setup: TCD/TCD/FID and FID/FPD
• Inline traps for high‐temperature sample streams

Main Results and Discussion

• The TCD/TCD/MSD system achieved detection limits of 10–400 ppm for light gases and 18–31 amu ion monitoring for polar compounds with minimal chromatographic overlap.
• Custom dual‐GC instrumentation enabled simultaneous measurement of paraffins, olefins and H₂S in fuel‐cell effluent, demonstrating robust performance at elevated temperatures.
• Real‐time monitoring via constant aspiration mass spectrometry provided continuous data when GC/MS was offline.

Benefits and Practical Applications

These customized GC solutions deliver comprehensive profiling of complex gas mixtures in petrochemical and clean-energy applications. The multi‐detector approach ensures low detection limits, fast turnaround and simultaneous multi-component quantification, supporting process optimization, quality assurance and regulatory reporting.

Future Trends and Opportunities

Ongoing trends include integration of online sampling and data analytics for predictive process control, enhanced sensitivity via novel detector materials, and miniaturized GC platforms for field deployment. Coupling GC with machine learning will further streamline method development and troubleshooting.

Conclusion

Wasson‐ECE’s tailored GC configurations demonstrate the versatility and precision of multi-detector chromatographic systems for challenging gas analyses. These case studies highlight the importance of instrument customization, optimized separation strategies and real-time detection in modern analytical laboratories.