GC Analysis of Sulfur Components in Propylene using a Sulfur Chemiluminescence Detector

Significance of the Topic

The analysis of trace sulfur compounds such as hydrogen sulfide, carbonyl sulfide and methyl mercaptan in light hydrocarbon streams is critical due to their corrosive, toxic and odorous properties. Accurate quantification at low parts-per-billion (ppb) levels is needed to prevent equipment damage, catalyst poisoning and process inefficiencies. Traditional sulfur detectors often suffer from matrix overload and quenching effects when analyzing high concentrations of hydrocarbons.

Study Objectives and Overview

This application note evaluates the performance of the Agilent J&W Select Low Sulfur capillary PLOT column coupled with a Sulfur Chemiluminescence Detector (GC-SCD) for the separation and detection of H2S, COS and CH3SH in a propylene matrix at ppb levels.

Methodology

The method employs gas chromatography with a sulfur-specific chemiluminescence detector. Key parameters include:

• Column: Agilent J&W Select Low Sulfur, 60 m × 0.32 mm (p/n CP8575)
• Oven program: 65 °C hold for 4 min, ramp at 30 °C/min to 120 °C, hold 5 min
• Carrier gas: Helium at 2.0 mL/min (constant flow)
• Injection: Split 1:10 at 200 °C via gas sampling valve (1 mL loop)
• Detector: SCD at 200 °C

Instrumentation

The system configuration comprises:

• Gas chromatograph equipped with a gas sampling valve
• Sulfur Chemiluminescence Detector (SCD)
• Agilent J&W Select Low Sulfur capillary column

Detector settings:

• Burner temperature: 800 °C
• Burner vacuum: 370 torr
• Reactor hydrogen flow: 40 mL/min
• Reactor air flow: 65 mL/min
• Attenuation: 1
• Ozone air pressure: 5 psig

Key Findings and Discussion

The novel stationary phase provides baseline resolution between the sulfur analytes and the propylene matrix, eliminating quenching and enhancing detector sensitivity. Chromatograms demonstrate clear peaks for H2S, COS and CH3SH at ~300–500 ppb in propylene, with no interference from the matrix. The column’s high loadability and unique selectivity enable reliable detection down to 20 ppb for H2S. The PLOT design prevents particle shedding, allowing safe use with switching valves.

Method Benefits and Practical Applications

• Baseline separation of sulfur species from hydrocarbon matrix to avoid quenching
• Low ppb detection limits for environmental and process monitoring
• Robust performance with reactive sulfur compounds
• Compatibility with gas sampling valves and online process streams

Future Trends and Applications

Advancements may include integration of the low-sulfur column with real-time process analyzers, miniaturized GC-SCD modules for field deployment, and expansion to other hydrocarbon matrices. Further method automation and coupling with complementary detectors could broaden its analytical scope.

Conclusion

The Agilent J&W Select Low Sulfur column in conjunction with a GC-SCD offers a powerful solution for trace-level sulfur analysis in propylene. By delivering exceptional separation and sensitivity while mitigating matrix effects, this approach supports rigorous quality control and environmental compliance in petrochemical operations.

References

1. W. Wardencki (1998) Review “Problems with the determination of environmental sulphur compounds by gas chromatography.” J. Chromatog. A. 793: 1–19.
2. Roger L. Firor and Bruce D. Quimby, “Comparison of Sulfur Selective Detectors for Low-Level Analysis in Gaseous Streams,” Agilent Technologies publication 5988-2426EN.