Determination of perchlorate in drinking water using a compact RFIC ion chromatography system

Importance of the Topic

Perchlorate is a persistent anion of regulatory concern in drinking water due to its interference with thyroid hormones and potential developmental effects. Accurate, sensitive, and reliable detection of trace perchlorate supports public health monitoring and compliance with EPA and ISO guidelines.

Objectives and Study Overview

This study evaluates the performance of a compact Thermo Scientific Dionex Inuvion ion chromatography system configured with a Dionex IonPac AS16-4 µm column, suppressed conductivity detection, and reagent-free eluent generation for quantifying perchlorate in municipal drinking water according to EPA Method 314.0 and ISO 19340.

Methodology and Instrumentation

Reagents and Standards:

• Type I deionized water, 18 MΩ·cm
• Sodium perchlorate standard solutions (1–50 µg/L)
• Anion interferences: chloride, sulfate, carbonate, nitrate, bromide, nitrite, phosphate, iodide, thiosulfate, thiocyanate, 4-chlorobenzenesulfonic acid

Instrumentation:

• Dionex Inuvion IC system with column heater, pump degas module, RFIC eluent degasser
• Dionex IonPac AS16-4 µm analytical column (2 × 250 mm) with AG16 guard column (2 × 50 mm)
• Eluent: 65 mM KOH generated by EGC 500 KOH cartridge and CR-ATC 600 trap column
• Autosampler: Dionex AS-DV (5 mL PolyVials)
• Suppressor: Dionex ADRS 600, 62 mA constant current, recycle mode
• Detection: suppressed conductivity
• Software: Chromeleon CDS v7.3.2

Method Parameters:

• Flow rate: 0.38 mL/min
• Column temperature: 30 °C
• Injection volume: 250 µL
• Runtime: 12 min
• System backpressure: ~3,800 psi
• Background conductance: <1.4 µS/cm; noise: <1.1 nS/cm

Main Results and Discussion

Calibration showed excellent linearity for perchlorate over 1–50 µg/L (r² = 0.99965) without forcing through zero. Chromatograms of 25 µg/L perchlorate in various matrices (DI water, 200 mg/L and 1,000 mg/L chloride, sulfate, carbonate) demonstrated clear peak resolution and minimal interference. Analysis of four municipal drinking water samples yielded perchlorate concentrations of 0.83–0.94 µg/L in two samples, with non-detects in the others. Spike recovery at 4 µg/L ranged from 86 % to 100 %, confirming method accuracy.

Benefits and Practical Applications

The compact Dionex Inuvion IC system offers reagent-free eluent generation, robust suppression, and streamlined operation. It meets regulatory requirements for perchlorate monitoring in drinking water with low detection limits, high throughput, and minimal maintenance. This approach supports routine water quality testing in environmental, municipal, and industrial laboratories.

Future Trends and Potential Applications

Advancements in ion chromatography may include further miniaturization, automated sample preparation, and integration with mass spectrometry for expanded anion profiling. Emerging sensor technologies and data analytics could enhance in-field monitoring and real-time water quality assessment.

Conclusion

The Thermo Scientific Dionex Inuvion IC system equipped with a Dionex IonPac AS16-4 µm column and RFIC reagent-free eluent generation reliably determines perchlorate in drinking water at trace levels. The method aligns with EPA Method 314.0 and ISO 19340, delivering accurate, linear, and reproducible results suitable for routine environmental compliance testing.

References

• U.S. EPA Method 314.0; U.S. Environmental Protection Agency; Cincinnati, OH, 1997.
• Thermo Fisher Scientific Application Update 148: Determination of perchlorate in drinking water using a reagent-free ion chromatography system.
• Thermo Fisher Scientific Application Note 73267: Determination of perchlorate in drinking water using ion chromatography.
• International Organization for Standardization. Water quality – Determination of dissolved perchlorate – Method using ion chromatography (IC). ISO 19340:2017.