Rapid Greenhouse Gas Analysis via the Nexis GC-2030 Gas Chromatograph

Importance of the Topic

The rapid and accurate quantification of greenhouse gases such as methane, carbon dioxide and nitrous oxide is critical for environmental monitoring, industrial emissions control and climate research. A compact, high-throughput gas chromatographic system capable of sub-ppm detection can streamline analyses in laboratories, improve data reliability and support regulatory compliance.

Study Objectives and Overview

This study presents an optimized configuration of the Nexis GC-2030 gas chromatograph for the simultaneous analysis of three primary greenhouse gases. The goals were to achieve full chromatographic resolution in under three minutes, determine limits of detection (LOD) and quantitation (LOQ), evaluate repeatability, and demonstrate selective heart-cutting to vent potentially interfering or catalyst-damaging compounds.

Methodology and Instrumentation

The system employs parallel analytical lines with independent capillary columns and timed switching valves to separate permanent gases, greenhouse gases and possible interferents.

Instrumentation:

• Gas chromatograph: Shimadzu Nexis GC-2030 equipped with ECD Exceed-2030 and FID-2030 with Jetanizer in-jet methanizer
• Capillary columns: SH-RT-Q-BOND (30 m × 0.53 mm × 20 μm) and RT-QS-BOND (30 m × 0.53 mm × 20 μm)
• Sample introduction: 1 mL gas loop via 6-port sampling valve; optional AOC-6000 Plus autosampler for Exetainer vials
• Valve configuration: solenoid valve on FID line for heart-cut venting; 6-port switching valve on ECD line for permanent gas preflush

Analytical conditions:

• Injector temperature: 250 °C, split ratio 5:1
• Carrier gas: nitrogen, linear velocity 35.7 cm/s
• Oven: isothermal at 35 °C
• FID: 400 °C; makeup He 24 mL/min, H2 32 mL/min, air 250 mL/min
• ECD: 325 °C; P5 flow 15 mL/min; current 2.0 nA

Main Results and Discussion

Standard 1 (600 ppm CO2, 5 ppm CH4, 1 ppm N2O) yielded fully resolved peaks in under 2.5 min. Triplicate injections produced RSD values <1% for all analytes. Calculated LODs were approximately 0.37 ppm for methane, 0.39 ppm for carbon dioxide and 0.10 ppm for nitrous oxide; LOQs were near 1 ppm for CH4/CO2 and 0.31 ppm for N2O.

Standard 2 (including light hydrocarbons and high permanent gas levels) was analyzed in under 3.5 min. The Jetanizer-FID line exhibited minimal baseline disturbance from oxygen or permanent gases, enabling accurate detection of carbon monoxide and hydrocarbons. Heart-cutting of acetylene to vent improved repeatability, reducing RSD from around 1% to under 0.3% without significant baseline artifacts or peak shifts.

Benefits and Practical Applications

The described GC configuration delivers:

• Fast turnaround: full analysis in under 3.5 min
• High sensitivity: sub-ppm LODs for key greenhouse gases
• Robust repeatability: RSDs consistently below 1%
• Selective venting: heart-cut capabilities protect methanizer catalysts and prevent interference
• Scalability: optional autosampler integration for high throughput

This approach is well suited for environmental monitoring, emission source profiling, industrial process control and research laboratories requiring rapid greenhouse gas quantitation.

Future Trends and Applications

Potential developments include the expansion of analyte scope to other trace gases or volatile organics, integration with automated sampling systems for field deployment, and coupling with isotope ratio mass spectrometry for advanced source apportionment. Further miniaturization or flow-modulated designs could enable portable greenhouse gas analyzers for in-field screening.

Conclusion

The optimized Nexis GC-2030 system achieves rapid, sensitive and repeatable analysis of methane, carbon dioxide and nitrous oxide in a streamlined flow path. Low detection limits, heart-cut venting and autosampler compatibility make this configuration a versatile tool for greenhouse gas monitoring and research.

References

• Shimadzu Scientific Instruments Application Note No. SSI-GC-2109 Rapid Greenhouse Gas Analysis via the Nexis GC-2030 Gas Chromatograph, First Edition, July 2021