Elemental Analysis: Fully automated double channel analysis for CHNS determination by TCD Detector and trace sulfur by FPD Detector

Importance of the Topic

Combustion-based determination of carbon, hydrogen, nitrogen, and sulfur is a fundamental analytical approach for quality control and research in materials, petrochemicals, pharmaceuticals, soils, and polymers. High throughput, automated workflows reduce cost per sample and improve reproducibility, meeting modern laboratory demands.

Objectives and Study Overview

This note evaluates the performance of a dual-channel elemental analyzer configured for CHNS analysis with a thermal conductivity detector and trace sulfur analysis with a flame photometric detector. The goal is to demonstrate accuracy, repeatability, rapid channel switching, and reduced carrier gas consumption under continuous operation.

Methodology and Instrumentation

The analyzer features two independent furnaces, each with its own autosampler and gas circuit, managed by a multi-valve control module and a dedicated data handling software. For CHNS:

• Dynamic flash combustion in oxygen
• Helium carrier passes combustion gases through copper reagent and GC column
• Detection by thermal conductivity detector, total run time under 10 minutes

For trace sulfur:

• Similar flash combustion in second furnace
• Helium flow through copper, water trap, GC column
• Flame photometric detection, run time under 5 minutes

Calibration used methionine standard (2–3 mg, K-factor) for CHNS and pasta reference material (0.5–2 mg, quadratic fit) for sulfur. Automated channel switching and carrier gas substitution (to nitrogen or argon in standby) optimize helium usage.

Instrumentation Used

• Dual-furnace FlashSmart elemental analyzer
• MultiValve Control module
• MAS Plus autosampler
• Thermal conductivity detector
• Flame photometric detector
• EagerSmart data handling software

Key Results and Discussion

Repeated analyses of sulfanilamide and standard reference materials demonstrated:

• CHNS results within 16.27 ± 0.16% N, 41.84 ± 0.30% C, 4.68 ± 0.07% H
• Sulfur determination at 18.62 ± 0.20% for sulfanilamide and 0.136 ± 0.004% for pasta standard
• Rapid stabilization (under ten minutes) after channel switching
• Consistent outcomes across diverse matrices (soils, catalysts, graphene, carbon fiber, liquid solutions)
• No interference from hydrogen, no sulfur adsorption in traps or columns, and complete gas conversion

Benefits and Practical Applications

The fully automated dual-channel system increases throughput by enabling back-to-back CHNS and sulfur analyses without manual reconfiguration. Gas consumption is minimized by stand-by mode switching. Applications span environmental testing, polymer quality control, catalyst development, and materials research.

Future Trends and Potential Applications

Expansion of dual-channel configurations may include additional element pairs (CHN/O, NC/S, protein nitrogen with sulfur, etc.). Further integration with advanced software for predictive maintenance and remote operation will enhance laboratory efficiency and sustainability.

Conclusion

The dual-furnace elemental analyzer delivers reliable CHNS analysis from low ppm to 100% range and trace sulfur detection down to 5 ppm. Automated channel switching, robust repeatability, rapid run times, and low carrier gas usage make it a versatile solution for diverse analytical laboratories.