Configuring the Dionex Modular HPIC system with an inline water purifier and inline calibration for trace anion determinations in ultrapure water

Significance of the Topic

The analysis of trace anions at parts-per-trillion (ppt) to parts-per-billion (ppb) levels in ultrapure water is critical in high-technology industries such as electronics and power generation.
Even minute ionic contamination can lead to corrosion, device failures, yield loss, and shortened product life.
As device dimensions shrink, the demand for more sensitive and reliable ion monitoring increases.

Objectives and Study Overview

This work describes the step-by-step configuration and operation of a Thermo Scientific Dionex ICS-5000+ high-pressure ion chromatography (HPIC) system equipped with a Dionex EWP Electrolytic Water Purifier and a Dionex AutoPrep module.
The goal is to achieve automated calibration, inline water purification, and ppt-level anion determination in ultrapure water while preserving the second channel of the dual-IC system for alternative applications.

Methods and Instrumentation

The HPIC system was assembled with a dual pump (DP), eluent generator (EGC 500 KOH cartridge), high-pressure degasser, conductivity detector (CD) with AERS-500e suppressor, Dionex AS-HV autosampler, Dionex AutoPrep module, and Dionex EWP purifier module.
Instrumentation details include:

• IonPac AG17-C guard and AS17-C separation columns (4×50 mm and 4×250 mm).
• IonPac UTAC-LP2 concentrator column (4×35 mm) and CRD-300 carbonate removal device.
• Reagent-Free™ suppressor power via Dionex RFC-10 controller supplying 20 mA to the EWP module.
• Chromeleon 7.2 CDS software controlling modules, valve sequencing, and autosampler dosing.

A KOH gradient (1–35 mM over 30 min) at 1.0 mL/min and 35 °C separation temperature provided baseline conductivity below 1 µS.
Autosampler pull-mode loading (10 mL sample, ~3.5 mL/min) and inline degassing preceded concentration and injection.
Calibration standards (50–250 ppt apparent) were prepared by incremental 10 µL aliquots in the small AutoPrep loop, yielding high sensitivity and low contamination risk.

Main Results and Discussion

Inline water purification via the EWP module reduced baseline ions to below 1 µS, enabling reliable detection of fluoride, chloride, nitrite, bromide, nitrate, sulfate, and phosphate at single-digit ppt levels.
Calibration curves for all anions exhibited excellent linearity (r² ≥ 0.9989) from 50 to 250 ppt.
Estimated method detection limits ranged between 6 and 53 ppt, depending on the analyte.
Contaminant peaks (carbonate and minor organics) were effectively eliminated by the CRD-300 device upstream of the concentrator.

Benefits and Practical Applications

This configuration offers:

• Automated inline calibration and water purification for minimized environmental and system contamination.
• High sensitivity ppt-level determination without dedicated cleanroom facilities.
• Preservation of the second channel of the dual HPIC system for alternative methods.
• Reduced labor and improved reproducibility through sequenced valve and autosampler control.

Future Trends and Applications

Further advancements may include the integration of multiplexed EWP purifiers, smaller footprint HPIC systems, AI-driven method optimization, and expansion to additional analytes such as trace metals and organic acids.
Cloud-based data analysis and remote monitoring could further enhance laboratory efficiency and quality control in ultratrace applications.

Conclusion

The combination of Dionex ICS-5000+ HPIC, EWP Electrolytic Water Purifier, and AutoPrep module enables robust, automated, and highly sensitive trace anion analysis in ultrapure water.
This approach meets stringent industrial requirements, improves quantification accuracy, and frees bench space for multiple simultaneous applications.

References

1. Christison T., Khor D., Rohrer J. Technical Note 72206: Configuring the Dionex ICS-5000+ HPIC system with inline water purification and calibration for trace anion determinations; Thermo Fisher Scientific; 2016.
2. Thermo Fisher Scientific. Dionex AS-HV Autosampler Operator’s Manual, Doc. No. 065259; 2012.
3. Thermo Fisher Scientific. Dionex ICS-5000+ Ion Chromatography Installation and Operator’s Manual, Doc. Nos. 065446-065447; 2016.
4. Thermo Fisher Scientific. Dionex Reagent-Free Controller Operator’s Manual, Doc. No. 031880; 2016.
5. ASTM International. ASTM D 5127 Standard Specification for Reagent Water; ASTM International; latest edition.