Combustion IC System

Significance of the Topic

The accurate determination of halogens (fluorine, chlorine, bromine, iodine) and sulfur in complex matrices is critical across petrochemical, pharmaceutical, polymer, and environmental sectors. These elements can cause catalyst poisoning, corrosion of process equipment, environmental pollution, and regulatory non-compliance. Traditional sample preparation techniques such as acid digestion or solvent extraction are labor-intensive, time-consuming, and generate hazardous waste. Combustion Ion Chromatography (CIC) offers an automated, robust alternative that minimizes sample handling, reduces analysis time, and enhances accuracy and reproducibility.

Study Objectives and Overview

This application note introduces a fully automated CIC workflow for the qualitative and quantitative analysis of halogens and sulfur in challenging samples. It outlines the theoretical basis of CIC, describes system components, and highlights major applications including petrochemicals, coal, polymers, inks, and electronic materials. Emphasis is placed on achieving compliance with international methods (e.g., ASTM D7994) and demonstrating method performance in terms of sensitivity, precision, and multi-element capability.

Methodology and Used Instrumentation

Samples (solids, semisolids, liquids, gases) are weighed into quartz boats and introduced into a high-temperature horizontal furnace (800–1100 °C) under an oxygen atmosphere. Thermal decomposition converts organic S to SOx and organic/inorganic halogens to HX or X2 species. Combustion vapors are swept into an aqueous absorbing solution containing hydrogen peroxide (to oxidize SO2 to SO3) and phosphate as an internal standard.

• Combustion Unit: Mitsubishi AQF-2100H horizontal furnace with ASC-240S automatic boat controller (pyrolysis at 800–1100 °C).
• Gas Supply: Oxygen for oxidation; Argon for carrier control as needed.
• Absorption Module: Thermo Scientific Dionex GA-210 gas absorption unit — heat-resistant glass absorption tube (10 or 20 mL), six-way valve, high-pressure pump (5 mL, PEEK/Teflon).
• Ion Chromatograph: Thermo Scientific Dionex Integrion HPIC or Aquion IC systems equipped with Thermo Scientific Dionex ERS 500 suppressors (or DRS 600 for dual channels), Chromeleon CDS, conductivity detectors.

Key Results and Discussion

1. Petrochemicals: Chloride and sulfate concentrations measured in refinery intermediates showed sharp, well-resolved peaks with retention times around 2–6 minutes and detection limits below 0.1 mg/kg.
2. Coal Analysis: Ground coal samples produced reproducible fluoride, chloride, and sulfate signals (overlay of three injections yielded <2 % RSD). Internal phosphate standard ensured accuracy across runs.
3. Printing Inks and Dyes: Organic matrices were fully decomposed, eliminating matrix interferences. Chloride, fluoride, nitrate, and sulfate were quantified with high sensitivity, supporting quality control in cartridge manufacturing.
4. Electronic Components: RoHS compliance testing for bromine content showed reliable detection of residual bromide with <5 % deviation. Absence of bromide confirmed the removal of banned flame retardants.

Benefits and Practical Applications

• Automation: Reduces manual sample preparation and associated errors.
• Versatility: Analyzes solids, liquids, gases, and viscous materials without prior extraction.
• Speed: Complete analysis within 10–15 minutes per sample.
• Environmental Safety: Minimizes use of strong acids and organic solvents.
• Regulatory Compliance: Meets ASTM D7994 and other international standards for F, Cl, Br, I, and S in LPG, polymers, lubricants, soil, and ores.

Future Trends and Opportunities

Advancements are expected in miniaturized CIC modules for field-deployable analysis, integration with mass spectrometry detectors for speciation studies, and development of new absorbent chemistries to expand detection of emerging halogenated contaminants. Machine-learning algorithms may optimize combustion parameters and chromatographic separation in real time, further enhancing throughput and data quality.

Conclusion

Combustion Ion Chromatography provides a powerful, fully automated solution for the determination of halogens and sulfur in complex matrices. The technique delivers high precision, low detection limits, and regulatory compliance while significantly reducing sample preparation time and environmental impact. Its broad applicability makes it an essential tool for industrial laboratories, environmental monitoring, and quality control.

References

• ASTM D7994—Standard Test Method for Halogen and Sulfur Determination in LPG by Combustion Ion Chromatography.
• Thermo Fisher Scientific Application Note: Determination of Halogens in Coal Using Combustion Ion Chromatography.
• Thermo Fisher Scientific Application Note: Determination of Adsorbable Organic Halogen in Wastewater Using CIC.