Combustion Ion Chromatography

What is combustion ion chromatography?

Halogens (fluorine, chlorine, bromine, iodine) and sulfur are potentially corrosive, hazardous chemicals that contribute to environmental pollution. However, determining these analytes in petrochemicals, gaseous samples, solid samples, and complex chemicals cannot be easily done using conventional ion chromatography (IC) and the sample preparation required can be costly and labor intensive. Combustion IC (C-IC) is a hyphenated IC technique that reduces the time and labor for determination of halogens and sulfur in difficult samples by eliminating these complex sample preparation steps. This automated technique is sensitive, saves time, and produces fewer environmental contaminants than other sample preparation techniques, such as acid digestions or back extractions from organic solutions.

How does combustion IC work?

Combustion IC consists of four main steps:

Introduce sample
Liquid, solid or semisolid samples are introduced into a horizonal furnace at a precisely controlled rate. An autosampler can be used to automate sample delivery or, for gaseous samples, an injector is used.
Perform pyrolysis
Samples are decomposed in the presence of humidified oxygen at high temperature (800–1100˚C).
Trap volatiles
Volatile products are trapped in an aqueous absorbing solution, which may contain phosphate as an internal standard for calibration.
Perform ion analysis
Samples in the absorption solution are transferred to the IC system to determine the concentrations of individual halides and sulfur species (e.g., sulfite, sulfate, and thiosulfate). Total sulfate can be determined by further oxidizing the sulfur species by using hydrogen peroxide in the absorption solution.

Combustion IC for halogens and sulfur

C-IC provides accurate and reproducible results for the analysis of halogens and sulfur in a variety of environmental, industrial, and food and beverage samples, often in less than 12 minutes, with minimal method development. Sample types include pharmaceutical raw materials and finished products, polymers, petrochemicals, ores, inks, metals, polishing agents, lubricating oil, electronic components, and environmental or wastewaters.

PFAS analysis using C-IC

C-IC can be used as a complementary screening technique to LC-MS/MS for the analysis of per- and polyfluoroalkyl substances (PFAS) by determining total adsorbable organic fluorine (AOF) as an indicator of the presence of fluorinated compounds. If the total mass of fluorine present in the sample exceeds that of the targeted PFAS screen, then other PFAS that were not on the target list may be present in the sample. By screening total fluorine, labs can identify additional potential sources contributing to PFAS contamination, enabling them to select and analyze only “suspicious” samples using LC-MS/MS instrumentation. With the addition of AOF determination by C-IC, labs can optimize the utilization of their analytical instrumentation to analyze PFAS in water.

In addition to water, C-IC can also be used to determine PFAS in other materials, such as textiles and cosmetics. These materials can contain much higher concentrations of PFAS than water and do not require a concentration step, which is necessary AOF determinations.

Learn more about our PFAS analysis solutions

Detailed C-IC methods can be found in the Thermo Scientific AppsLab Library of Analytical Applications.