Analysis of an ion exchanger applying Metrohm Combustion IC

Significance of the Topic

Ion exchange resins are key in production of ultrapure water for pharmaceutical and semiconductor industries. Quality of resins directly impacts purity levels. Reliable analytical techniques for residual ion content support quality control and ensure compliance with stringent purity standards.

Objectives and Study Overview

This study evaluates Metrohm Combustion IC for quantification of anionic contaminants in a polystyrene divinylbenzene based ion exchange resin. Goals include method setup, determination of chloride and sulfur content, and assessment of precision and reproducibility.

Methodology

Sample preparation and analysis followed the protocol below

• Drying of wet resin at 105 °C in an oven with waste air removal
• Combustion IC analysis using flame sensor technology and intelligent partial loop injection
• Sequential suppression conductivity detection of combustion gases
• Use of inline matrix elimination to reduce interferences
• Measurement parameters included a 100 µL injection volume, 0.7 mL per minute eluent flow and a 20 minute total run time
• Combustion conditions set to 1050 °C oven temperature with argon and oxygen streams

Applied Instrumentation

• 881 Compact IC pro Anion Module with MCS and conductivity detector
• 920 Absorber Module and Combustion Module
• Autosampler MMS 5000 and kit for solid samples
• Metrosep A Supp 5 150 4.0 and associated guard and separator columns

Results and Discussion

The method yielded mean chloride concentration of 90.6 g per kg resin with relative standard deviation of 3.5 percent and mean sulfur content of 57.3 g per kg with RSD below 1 percent. Nitrite and nitrate peaks were present but not used for nitrogen quantification due to interference. Precision and sensitivity meet industry requirements for resin quality control.

Benefits and Practical Applications

• Rapid and accurate quantification of residual anions in solid ion exchange materials
• High sensitivity for chloride and sulfur analysis
• Robust workflow suitable for routine quality assurance in pharmaceutical and semiconductor contexts
• Minimal sample preparation and automated operation reduce hands on time

Future Trends and Opportunities

Expansion of combustion IC to a wider range of resin types and polymer matrices is expected. Integration with advanced data processing and machine learning may further enhance defect detection. Development of multi element detection channels and higher throughput automation will support larger sample volumes in industrial quality control.

Conclusion

Metrohm Combustion IC offers a reliable, sensitive and efficient approach for assessing anionic purity in ion exchange resins. The method demonstrates excellent reproducibility and aligns with quality requirements of high purity water production applications.

References

• Metrohm Combustion IC Application Note CIC 011