IonPac AS15 Anion-Exchange Column

Importance of the Topic

High‐purity water in semiconductor fabrication and power generation must be free of inorganic anions and low molecular weight organic acids at trace levels to avoid corrosion, contamination, and process disruptions. Sensitive, reliable analysis down to ppb and ppt concentrations is crucial for product quality, equipment longevity, and compliance with industry standards.

Objectives and Overview

This study examines the performance of the IonPac AS15 anion‐exchange column for the isocratic and gradient separation of common inorganic anions including fluoride, chloride, nitrite, carbonate, sulfate, bromide, nitrate, and phosphate as well as monovalent organic acids such as glycolate, formate, and acetate in high‐purity water matrices. The aim is to demonstrate rapid analysis, low background, high capacity, and compatibility with preconcentration techniques to achieve ultratrace detection levels.

Methodology

Analyses were performed using hydroxide eluent generated electrolytically and conductivity detection with suppression. Isocratic runs on 3 × 150 mm and larger formats provided separation in 15 to 25 minutes. A gradient profile was applied for wider organic acid panels. Large‐loop injections and online preconcentration using concentrator columns extended detection limits to sub‐ppb and ppt levels. Temperature control at 30 °C ensured retention time reproducibility.

Instrumentation Used

• Ion chromatography systems equipped with Eluent Generator (EG40) and ASRS-ULTRA or ACES 300 suppressors
• IonPac AS15 columns: 5 µm (3 × 150 mm), 9 µm (4 × 250 mm, 2 × 250 mm), and capillary format (0.4 × 250 mm)
• Anion trap columns (CR-ATC, ATC-HC) for contaminant removal in eluent lines
• Concentrator columns (AC15, IonSwift MAC-100) for sample enrichment and ppt‐level analysis

Main Results and Discussion

The AS15‐5 µm column delivered baseline resolution of eight inorganic anions in under 15 minutes with large‐loop injection detection down to 0.018 µg/L for fluoride. The high‐capacity AS15‐9 µm formats extended linear range and preserved peak shape in samples with high co‐ion concentrations. The capillary column with online preconcentration achieved 0.1 µg/L detection of multiple anions from 20 mL sample volumes. Gradient operation enabled simultaneous analysis of weakly retained organic acids and strong inorganic anions with good peak symmetry and retention reproducibility.

Benefits and Practical Applications

• Fast routine analysis of trace anions and organic acids in ultraclean water
• Wide dynamic range supporting ppb to high‐ppm quantification in complex matrices
• Low background and stable baseline from pure hydroxide eluent generation
• Flexibility to transfer methods across capillary, 3 mm and 4 mm formats for eco-friendly, high‐sensitivity workflows
• Online preconcentration simplifies ultratrace monitoring in semiconductor, power plant, and pharmaceutical water systems

Future Trends and Applications

Advances in microbore and capillary formats with further reduced eluent consumption will drive greener analytics. Integration of multi‐dimensional IC×IC systems can enhance selectivity for emerging contaminants. Automated sample preparation and real-time monitoring through inline preconcentration modules will support continuous quality control in high‐purity water loops. Ongoing development of novel stationary phases may extend the method to a broader range of polar and charged analytes.

Conclusion

The IonPac AS15 column family, combined with electrolytic eluent generation, suppressed conductivity detection, and concentrator technology, provides a versatile solution for high‐capacity, trace‐level analysis of anions and organic acids in high‐purity water. The system meets the demands for speed, sensitivity, and robustness required by semiconductor and power generation industries.