N2O/CO/CO2/CH4 analysis system (TCD) Nexis GC-2030NCCC3 GC-2014NCCC3

Importance of the topic

Monitoring of trace and permanent gases such as N₂O, CH₄, CO and CO₂ is critical in environmental research, agricultural studies and industrial process control. Accurate quantification of N₂O emissions from soil informs greenhouse gas budgets, while simultaneous analysis of major atmospheric gases supports climate modelling and quality assurance in gas production and distribution.

Objectives and study overview

This work demonstrates a gas chromatographic method for concurrent determination of nitrous oxide released from soil and permanent gases (CH₄, CO, CO₂, N₂, O₂). The system is configured to deliver high sensitivity for N₂O via Electron Capture Detection (ECD) and robust quantification of other components with Thermal Conductivity Detection (TCD), achieving rapid separation in under ten minutes.

Methodology and instrumentation

• Gas chromatograph equipped with five switching valves and seven packed columns.
• Detector arrangement: one ECD channel for N₂O, one TCD channel for CH₄, CO, CO₂, N₂ and O₂.
• Channel 1 path: sample loop → HayeSep-D column → ECD for N₂O detection.
• Channel 2 path: dual Porapak-N columns (first as pre-column to remove C₂ compounds, second to fractionate air/CH₄/CO from CO₂) → MS-13X column for air/CH₄/CO separation → Porapak-Q column and TCD for CO₂; downstream TCD also records N₂ and O₂.
• Control and data processing via LabSolutions GC workstation software.

Main results and discussion

• N₂O: linear response from 50 ppb to 100 ppm (ECD).
• CH₄, CO, CO₂: quantification range 0.01 % to 10 % (TCD).
• N₂ and O₂: measured from 0.01 % to 20 % (TCD).
• Chromatograms exhibit baseline separation of all target compounds within a 9-minute runtime.
• Repeatability is demonstrated by consistent peak areas over multiple injections.

Benefits and practical applications

• Simultaneous multi-component analysis reduces sample throughput time and instrumentation footprint.
• High sensitivity for trace N₂O supports low-level environmental monitoring.
• Robust TCD channel enables accurate measurement of major gas constituents for process control.
• Modular valve and column arrangement offers flexibility for method adaptation.

Future trends and potential applications

Integration of pre-concentration techniques could further lower detection limits for trace gases. Advances in micro-packed columns and high-resolution detectors may improve analysis speed and sensitivity. Coupling with isotope ratio mass spectrometry could enable simultaneous isotopic studies of N₂O, enhancing source apportionment in environmental research.

Conclusion

The described GC-ECD/TCD configuration provides a versatile and reliable approach for concurrent analysis of nitrous oxide and permanent gases. Its combination of sensitivity, selectivity and throughput makes it suitable for environmental monitoring, agricultural emissions studies and industrial QA/QC.

Reference

Shimadzu Corporation, Application Note SGC-ADS-0059, First Edition November 2017