Analysis of Inorganic Gas

Importance of Inorganic Gas Analysis

Inorganic gases such as argon, oxygen, nitrogen, methane and carbon monoxide play critical roles in petrochemical streams, environmental monitoring and quality control procedures. Accurate and reliable quantification of these species ensures process safety, regulatory compliance and optimized production efficiency.

Objectives and Study Overview

This application note presents a GC-MS based method for the separation and detection of light inorganic gases using a 5Å molecular sieve capillary column. The goal is to achieve clear resolution of five target gases in a single analytical run, demonstrating reproducible retention times and sensitivity suitable for industrial and research laboratories.

Methodology and Instrumentation

The method employs gas chromatography–mass spectrometry with the following general conditions:

• Column: 30 m × 0.32 mm I.D., 30 µm film thickness molecular sieve (5A)
• Oven program: 35 °C hold 2 min, ramp 10 °C/min to 150 °C, hold 5 min
• Injection: 1 mL gas loop, split ratio 1:50, injector at 200 °C
• Carrier gas: Helium, constant pressure at 100 kPa
• Detector: Mass spectrometer in scan mode (m/z 10–100), EI ionization at 200 °C

Instrumentation Details

• Gas Chromatograph–Mass Spectrometer: GCMS-QP2010 Ultra
• Column: SH-Msieve 5A, P/N 227-36611-02
• Gas sampler unit: P/N 223-57653-91, 1 mL loop
• MS interface and ion source temperature: 200 °C
• Emission current: 150 µA

Main Results and Discussion

The method achieved baseline separation of five gases within a single run. Retention order and approximate elution times:

• Argon (Ar)
• Oxygen (O₂)
• Nitrogen (N₂)
• Methane (CH₄)
• Carbon monoxide (CO)

The scan mode provided clear mass spectra for each component, facilitating unambiguous identification and quantitation. The high split ratio minimized matrix effects and ensured linear response over typical concentration ranges.

Benefits and Practical Applications

• Rapid, simultaneous analysis of multiple inorganic gases
• Robust separation with minimal interference
• High sensitivity and reproducibility suitable for QA/QC
• Applicability to petrochemical, environmental and industrial gas streams

Future Trends and Possibilities for Use

Advancements may include faster temperature programming, alternative carrier gases to reduce cost, and enhanced data processing algorithms for real-time monitoring. Integration with online sampling systems can enable continuous emission tracking and process control.

Conclusion

This GC-MS method using a 5Å molecular sieve column delivers reliable separation and detection of key inorganic gases. Its robustness and flexibility make it a valuable tool for laboratories focused on gas analysis in various industrial sectors.

Reference

Shimadzu Corporation. ERAS-1000-0424, First Edition March 2023.