Rt®-XLSulfur Packed Column Specialized packed and micropacked columns for eXtra-Low Sulfur analysis

Importance of the Topic

The determination of sulfur compounds at ultra-trace levels is essential for environmental compliance, industrial quality control, and prevention of catalyst poisoning. The need to detect ppb to ppbv concentrations drives innovation in column inertness and thermal stability for reliable gas chromatographic analysis.

Objectives and Overview of the Study

This work introduces Restek’s second-generation Rt®-XLSulfur packed and micropacked columns designed for extra-low sulfur analysis. The aim is to improve sensitivity and reproducibility for sulfur compound detection at sub-ppm levels compared to the first-generation Rt®-Sulfur column.

Methodology and Instrumentation

The key innovation lies in a specially deactivated porous polymer packing combined with Sulfinert®-treated tubing and fittings to minimize adsorption.

• Packing: Porous polymer phase with proprietary surface modification for enhanced inertness and thermal stability up to 300 °C.
• Transfer Lines: Sulfinert® coated stainless steel tubing and end-fittings offering metal passivation and rugged performance to 360 °C.
• GC Conditions (example):
  
  1. Oven temperature program: 60 °C to 230 °C at 15 °C/min.
  2. Carrier gas: Helium at 9 mL/min (constant flow).
  3. Detector: Sulfur chemiluminescence detector (SCD) or flame photometric detector (FPD).
  4. Injection: 1 mL of a 50 ppbv sulfur standard via sample valve.

Main Results and Discussion

The Rt®-XLSulfur column demonstrates resolution and quantitation of hydrogen sulfide, carbonyl sulfide, methyl and ethyl mercaptans, dimethyl sulfide and disulfide at 50 ppb levels. Key performance metrics include:

• Excellent peak symmetry and minimal tailing across all target analytes.
• Low baseline bleed allowing improved detector sensitivity and short conditioning times.
• Column-to-column reproducibility ensures consistent retention times and responses.

Benefits and Practical Applications

• Enhanced inertness reduces adsorption of reactive sulfur species, leading to lower detection limits in natural gas, petroleum and pulp mill streams.
• High thermal stability simplifies maintenance and extends column lifetime under rigorous temperature programs.
• Compatibility with standard GC platforms via a range of column configurations and instrument suffix codes.

Future Trends and Potential Applications

• Integration with on-line sampling systems and micro-GC devices for real-time sulfur monitoring.
• Coupling with mass spectrometry to expand compound libraries and improve discrimination of sulfur isomers.
• Development of even more inert stationary phases for sub-ppb detection in emerging environmental and energy sectors.

Conclusion

Restek’s Rt®-XLSulfur column offers a robust, high-inertness solution for trace sulfur analysis. Its second-generation design achieves ppbv detection limits, excellent reproducibility and broad compatibility with common GC detectors, addressing critical needs in industrial and environmental laboratories.

References

• Restek Corporation. Rt®-XLSulfur Packed Column for Extra-Low Sulfur Analysis. Lit. Cat. PCTS1500A-UNV, 2013.
• Restek Application Note PCAN1498-UNV. Analysis of Low-Level Sulfur Compounds in C1-C6 Hydrocarbon Streams. 2013.
• Restek Application Note PCAN1499-UNV. Analysis of Sulfur Compounds at ppb Levels Using Rt®-XLSulfur Micropacked and Rtx®-1 Columns. 2013.