Dual Plasma Sulfur and Nitrogen Chemiluminescence Detectors

Significance of the Topic

Accurate analysis of sulfur and nitrogen in complex matrices is critical for environmental monitoring, industrial quality control, catalyst protection, and flavor profiling. Trace levels of these elements can cause corrosion, catalyst poisoning, odorous emissions, and regulatory noncompliance. Highly sensitive and selective detection methods enable reliable quantification at parts‐per‐billion levels, supporting research, process optimization, and product safety.

Study Objectives and Overview

This study presents Agilent Technologies’ enhanced Sulfur Chemiluminescence Detector (355 SCD) and Nitrogen Chemiluminescence Detector (255 NCD) equipped with proprietary Dual Plasma Technology. The aim is to demonstrate improved stability, sensitivity, selectivity, linearity, and ease of use for gas chromatography (GC) and supercritical fluid chromatography (SFC) applications. Key goals include reducing maintenance, speeding start-up, and expanding application scope.

Methodology and Instrumentation

Dual Plasma Technology employs two hydrogen-oxygen flame plasmas to fully convert sample effluent into sulfur monoxide (SO) or nitric oxide (NO). These species react with ozone to produce chemiluminescent emissions. High‐temperature combustion (>1 800 °C) ensures complete conversion and minimal quenching. The Dual Plasma Burner accommodates major GC brands and features a low-temperature safety shroud. The Dual Plasma Controller integrates inline electronic flow sensors, digital display, programmable controls, and a compact footprint for rapid start-up and automated operation.

Used Instrumentation

• Agilent 355 Sulfur Chemiluminescence Detector (355 SCD)
• Agilent 255 Nitrogen Chemiluminescence Detector (255 NCD)
• Dual Plasma Burner and Controller
• Flame Ionization Detector (FID) Adapter for simultaneous hydrocarbon and heteroatom detection
• Dry Piston Oil-Free Vacuum Pump option
• Gas chromatograph equipped with CP Wax 52 column and split injector

Key Results and Discussion

Performance benchmarks demonstrate picogram‐level detection limits, equimolar and linear response, and absence of hydrocarbon quenching. Short-term precision for a benzene sample spiked with 1 ppm thiophene and 90 ppb sulfur from CS2 yielded 1.4 % and 2.6 % RSD, respectively. Over 72 hours, RSD remained below 4 % for thiophene and 11 % for carbon disulfide. Chromatograms illustrate baseline separation of 17 gasoline sulfur compounds, volatile sulfur species in beer, nitrosamines at low µg/mL levels, and simultaneous SCD/FID detection of sulfur and hydrocarbons in ultra-low sulfur diesel.

Benefits and Practical Applications

Key advantages include unmatched stability, sensitivity, and selectivity for sulfur and nitrogen speciation. Practical applications span:

• Petroleum and petrochemical analysis: fuels, monomers, solvents
• Natural gas and gaseous fuels by ASTM D5504 and D5623
• Trace thiophene in benzene per ASTM D7011
• Flavor and fragrance profiling in food and beverages
• Atmospheric emissions monitoring of H2S and NOx
• Detection of nitrosamines in environmental and consumer products
• Comprehensive two-dimensional GC and fast GC workflows

Future Trends and Opportunities

Emerging trends include coupling chemiluminescence detectors with mass spectrometry for structural identification, integration into automated high-throughput platforms, expansion into supercritical fluid chromatography, and deployment in portable environmental sensors for real-time field monitoring. Advances in plasma design and flow control may further reduce detection limits and broaden applicability to new sample types.

Conclusion

Agilent’s Dual Plasma‐enhanced 355 SCD and 255 NCD deliver industry-leading performance for sulfur and nitrogen analysis. The combination of superior sensitivity, selectivity, linear equimolar response, and streamlined operation addresses critical needs in research and industry. These capabilities enable more reliable, efficient, and versatile workflows across diverse analytical challenges.

References

1. ASTM D5504 – Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels
2. ASTM D5623 – Sulfur Compounds in Light Petroleum Liquids by GC with Sulfur Selective Detection
3. ASTM D7011 – Trace Thiophene in Refined Benzene by GC with Sulfur Selective Detection
4. US Patents 5 330 714; 5 227 135; 5 310 683; 5 501 981; 5 424 217; 5 661 032; 6 130 095; WO 95/22049
5. Agilent Technologies Application Note 5989-6102EN, December 2006