Analyses of Sulfur Gases at Trace and Low Percent Levels, Using Packed Column GC

Importance of the topic

Analysis of sulfur gases at trace and low percent levels is critical in environmental monitoring, industrial process control, and quality assurance. Sulfur compounds such as hydrogen sulfide, sulfur dioxide, carbonyl sulfide, mercaptans, sulfides and disulfides present analytical challenges due to their high mobility, chemical reactivity and very low concentration ranges from ppb to percent levels.

Objectives and study overview

This work evaluates six packed column gas chromatography packings designed specifically for separating key sulfur gases in air. The study presents Kovats retention indices for a range of sulfur and hydrocarbon compounds, compares separation performance of each packing, and demonstrates practical applications for trace and bulk analysis.

Methodology and instrumentation

All analyses were performed by packed column gas chromatography using flame photometric detection (FPD) or thermal conductivity detection (TCD). Carrier gases included nitrogen or helium at flow rates from 20 to 125 mL per minute. Columns ranged from 5 to 36 feet in length with inner diameters of 0.085 to 4 mm, packed with specialized deactivated stationary phases. Detector calibration was accomplished with permeation tube standards and exponential dilution to cover ppb to ppm concentration ranges.

Main results and discussion

Retention indices for methane through n-octane and over 20 sulfur compounds are tabulated for six packings: Chromosil 310, Chromosil 330, Carbopack B HT 100, Carbopack B with XE-60/H3PO4, 12 percent polyphenyl ether on Chromosorb T, and Supelpak-S. Key findings include:

• Chromosil 310 efficiently separates ppm levels of COS, H2S, CS2 and SO2 at up to 100 C.
• Chromosil 330 provides baseline separation of COS, H2S, SO2, CS2 and C1–C3 mercaptans at low temperature, extendable to alkyl sulfides at elevated temperature.
• 40/60 Carbopack B HT 100 delivers sub-ppb detection of H2S, SO2, COS and CH3SH with one-minute analysis on glass tubing at 25 C.
• Carbopack B/XE-60/H3PO4 resolves C2 isomers ethyl mercaptan and dimethyl sulfide, and separates SF6 along with light sulfur gases at ambient temperature.
• 12 percent polyphenyl ether on Chromosorb T separates a broad range of sulfur gases and hydrocarbons at 50 to 100 C with low bleed and high inertness.
• Supelpak-S offers rapid, low-backpressure analysis of Kraft pulp mill stack gases, water vapor, mercaptans, sulfides and disulfides up to 210 C.

Benefits and practical applications of the method

These tailored packings enable reliable, high-resolution separation of sulfur gases at trace to bulk levels without liquid phases or excessive column bleed. Applications include air pollution monitoring, process control in pulp and petrochemical plants, and quality control in industrial gas production.

Future trends and opportunities

Emerging developments in column deactivation, capillary stationary phases, multi-dimensional GC and advanced sulfur-selective detectors such as sulfur chemiluminescence or mass spectrometry promise further sensitivity, speed and selectivity. On-line and real-time monitoring platforms will benefit from compact, inert packings and integrated calibration approaches.

Conclusion

Packed column GC with specialized deactivated stationary phases provides versatile, robust solutions for sulfur gas analysis across a wide concentration range. Selection of the appropriate packing and operating conditions allows targeted separation of hydrogen sulfide, sulfur dioxide, carbonyl sulfide, mercaptans, sulfides, disulfides and tracer gases.

Reference

1. Bruner F, Liberti A, Possanzini M, Allegrine I Anal Chem 44 2070 1972
2. Bruner F, Ciccioli P, DiNardo F J Chromatogr 99 661 1974
3. Bremner JM, Banwart WL The Sulphur Institute Journal 10 1 1974
4. Stevens RK, Mulik JD, OKeefe AE, Krost KJ Anal Chem 43 827 1971
5. de Souza TLC, Lane DC, Bhatia SP Anal Chem 47 543 1975
6. Brody SS, Chaney JE J Gas Chromatogr 4 42 1966
7. Greer DG, Bydalek JT Environ Sci Tech 7 153 1973
8. Grice HW, Yates ML, David JD J Chromatogr Sci 8 90 1970
9. Ronkainen P, Denslow J, Lippanen O J Chromatogr Sci 11 384 1973
10. Stevens RK, OKeefe AE Anal Chem 42 142A 1970
11. OKeefe AE, Ortman GC Anal Chem 38 760 1966
12. Stevens RK, OKeefe AE, Ortman GC Environ Sci Tech 3 652 1969
13. Bruner F, Canuili C, Possanzini M Anal Chem 45 1790 1973
14. Bruner F, Ciccioli P, DiNardo F Anal Chem 47 141 1975