Trace level monitoring in deionized water using Process IC

Importance of the topic

Continuous monitoring of anions in industrial and environmental processes is essential for quality control, process optimization and regulatory compliance. Inline ion chromatography with preconcentration and matrix elimination enables real‐time tracking of trace anions, reducing downtime and ensuring product consistency.

Objectives and study overview

This application note presents the ProfIC Vario 12 Anion system, combining the 940 Professional IC Vario, 942 Extension Module Vario LQH and 941 Eluent Preparation Module. The goal is to demonstrate inline preconcentration with MiPCT‐ME (intelligent preconcentration with matrix elimination) for simultaneous determination of broad anion profiles under continuous operation, supported by an ELGA PURELAB Flex 6 ultrapure water supply.

Methodology and instrumentation

The method employs sequential suppression and conductivity detection after inline preconcentration and matrix elimination. Key parameters include a 2 000 µL injection volume, 0.18 mL/min flow rate, 30 °C column temperature and a 32 min run time. Ultrafilter modules prevent clogging and allow up to five parallel sample streams. Calibration spans 0.5 to 40 µg/L with an overall factor of 80.

Used instrumentation:

• 940 Professional IC Vario ONE/SeS with conductivity detector
• 942 Extension Module Vario LQH and 846 Dosing Interface
• 941 Eluent Production Module and Dosino regeneration
• Metrohm columns: Metrosep A Supp 5 (250/2.0), guard column and PCC 2 HC
• MiPCT‐ME inline preconcentration and matrix elimination kit
• ELGA PURELAB Flex 6 ultrapure water system

Main results and discussion

The system achieved a detection limit below 0.05 µg/L, repeatability within ±2 % and a dynamic range up to 3 200 µg/L. Typical recoveries for fluoride, chloride and bromide in deionized water were close to calibration levels, while acetate and phosphate were below quantifiable limits. Inline matrix elimination effectively removed interferences, yielding stable baselines and reproducible retention times.

Benefits and practical applications

• Real‐time, unattended monitoring of up to five sample lines
• Automated calibration and check standards via dedicated ports
• Reduced eluent consumption (~10 L/month) with narrow‐bore columns
• High sensitivity for trace anions in water and process streams
• Long‐term stability supported by continuous ultrapure water supply

Future trends and potential applications

The integration of process IC with digital control and predictive analytics will enhance proactive quality management. Advances in microfluidic preconcentration, novel suppressor chemistries and multi‐analyte detection promise further miniaturization and expanded monitoring capabilities in pharmaceutical, environmental and food industries.

Conclusion

The ProfIC Vario 12 Anion system demonstrates a robust, sensitive and fully automated solution for inline anion analysis. Its combination of MiPCT‐ME, ultrafiltration and continuous calibration meets the demands of modern process analytics, offering reliable data for operational decision‐making.