Environmental Water Analysis Applications Notebook

Importance of the topic

Environmental waters—including municipal wastewater, surface water, groundwater, and process effluents—are vital for human consumption, agriculture, and ecosystem sustainability. Contamination by inorganic anions and cations, perchlorate, hexavalent chromium, cyanide, organic acids, herbicides, and metals poses significant health and environmental risks. Regulatory agencies worldwide (e.g., U.S. EPA, European Commission, ISO, ASTM) set stringent limits and require reliable monitoring methods to safeguard water quality.

Objectives and study overview

This collection of application notes presents a comprehensive suite of ion chromatography (IC) methods for environmental water analysis using Thermo Scientific™ Dionex™ solutions. The primary goals are to outline robust techniques for detecting a wide range of inorganic and organic analytes at trace to high concentrations, demonstrate compliance with regulatory methods (e.g., EPA Method 300.0, EPA Method 314.2), and showcase advanced instrumentation and sample preparation strategies.

Methodology and Instrumentation

The work employs ion-exchange, ion-exclusion, and reversed-phase IC with suppressed conductivity or UV/visible and mass spectrometric detection. Key instrumentation and features include:

• Dionex ICS-5000+ and ICS-4000 High-Pressure IC systems with Reagent-Free IC (RFIC) for automated eluent generation and regeneration.
• Capillary and standard-bore Dionex IonPac columns (AS, CS, AG, CG, AS18, AS16, AS20, CS16, AS11-HC) tailored for anions, cations, cyanide, perchlorate, hexavalent chromium, and organic acids.
• Suppressed conductivity detectors (ASRS™, ASRS™ ULTRA, ACES™, CES™, CCES™) and pulsed amperometric detection (PAD) for chelating agents and total cyanide.
• Postcolumn derivatization (diphenylcarbazide) and UV/visible detection for hexavalent chromium; IC-MS and IC-MS/MS coupling for selective analysis of perchlorate, small organic acids, and herbicides (endothall).
• Automated sample preparation accessories including inline high-pressure filtration, Dionex OnGuard™ II and InGuard™ cartridges for matrix elimination, autosampler-based AutoDilution, and pH/conductivity prescreens.

Main Results and Discussion

Methods achieved rapid run times (<10–20 min) and low detection limits (sub-ppb to ppb) for target analytes across diverse matrices. Validation data demonstrated:

• Accurate quantification of inorganic anions/cations in drinking water, seawater, desalination streams, acid rain, hydraulic fracturing flowback, and high-salinity samples.
• Selective perchlorate determination at low µg/L levels using 2D-IC and IC-MS(/MS) approaches, overcoming sulfate and carbonate interferences.
• Sensitive hexavalent chromium detection (0.1 µg/L) via postcolumn derivatization and 2 mm columns.
• Robust cyanide and metal cyanide complex analysis by ICE-PAD and UV absorbance, with online preconcentration for µg/L detection.
• Reliable separation of organic acids and chelating agents in wastewater with online carbonate removal and PAD detection.

Benefits and Practical Applications

The described IC workflows provide:

• High automation and reproducibility through RFIC, autosampler accessories, and software-controlled sample dilution.
• Extended column and pump life via inline filtering and reagent-free operation.
• Regulatory compliance with established methods and enhanced selectivity for emerging contaminants.
• High throughput for routine water quality monitoring in government, municipal, and industrial laboratories.

Future Trends and Potential Uses

Emerging directions include:

• Further miniaturization and high-pressure capillary IC to reduce sample and solvent consumption.
• Expanded IC-MS/MS coupling for non-targeted screening of contaminants.
• Integration of inline sample preparation (SPE, concentrating traps) and real-time monitoring via portable IC systems.
• Advanced data analytics and machine learning for automated peak identification and quantification.

Conclusion

The Thermo Scientific Dionex IC portfolio offers a versatile, high-performance platform for comprehensive environmental water analysis. By combining advanced column chemistries, reagent-free operation, automated sample handling, and multi-mode detection, these methods deliver sensitive, reliable, and efficient monitoring solutions to meet current and future regulatory challenges.

Reference

No specific literature references were provided in the original application notes.