Analysis of tert-Butyl Mercaptan in Natural Gas on a CP-Sil 13 CB Using the Agilent 490 Micro GC

Importance of the Topic

Detection of trace levels of tertiary-butyl mercaptan in natural gas is critical for ensuring odorization standards, process safety, and regulatory compliance. Accurate and rapid analysis supports quality control, leak monitoring, and environmental protection in hydrocarbon processing and distribution.

Objectives and Study Overview

This application note exemplifies the use of the Agilent 490 Micro GC with a CP-Sil 13 CB column channel to separate and quantify tertiary-butyl mercaptan (TBM) in a natural gas matrix. The aim is to illustrate instrument setup, method conditions, and analytical performance in a streamlined workflow.

Methodology and Instrumentation

The analysis employs a CP-Sil 13 CB capillary column (channel dimensions optimized for sulfur compounds) maintained at 40 °C. Helium serves as the carrier gas at 250 kPa. Sample injection is executed in 255 ms. The Agilent 490 Micro GC platform offers five-generation ruggedness, portability, and lab-grade performance in field and laboratory environments.

Main Results and Discussion

TBM elutes just prior to 60 s, with complete chromatographic separation achieved within 100 s. The zoomed chromatogram confirms baseline resolution of TBM from other natural gas constituents. Quick cycle times enhance throughput and reduce analysis costs. Precision and reproducibility meet typical QC requirements for odorant monitoring.

Benefits and Practical Applications

• Rapid turnaround: total analysis under two minutes accelerates decision-making.
• Ease of use: minimal method development for routine monitoring.
• Portability: field-deployable platform for on-site testing.
• High resolution: reliable detection of TBM at low ppm levels.

Future Trends and Potential Applications

Integration of micro GC with wireless data transfer and automated sampling will facilitate real-time pipeline monitoring. Advances in detector sensitivity and miniaturization may extend applicability to other odorants and trace sulfur species. Coupling with chemometric tools can further enhance selectivity and reduce false positives.

Conclusion

The Agilent 490 Micro GC combined with a CP-Sil 13 CB column provides a fast, robust, and sensitive method for TBM analysis in natural gas. Its rapid cycle time, ease of operation, and portability make it an attractive solution for industry QC and safety applications.

Reference

Remko van Loon. Analysis of tert-Butyl Mercaptan in Natural Gas on a CP-Sil 13 CB Using the Agilent 490 Micro GC. Agilent Technologies Inc., May 27, 2011.