Hyphenated techniques as modern detection systems in ion chromatography

Importance of the Topic

Ion chromatography (IC) hyphenated with mass spectrometric detectors addresses critical needs in trace analysis by combining high separation efficiency with elemental and molecular specificity. These modern detection systems enable reliable quantification of environmental contaminants and speciation of potentially hazardous elements in complex matrices, fulfilling stringent regulatory requirements.

Objectives and Study Overview

This work evaluates two coupling approaches: IC–ESI-MS for oxyhalides (bromate, perchlorate) and organic acids in water, and IC–ICP-MS for multi-valent element speciation (chromium, arsenic, selenium) in environmental and industrial samples. The goal is to achieve sub-ppb detection limits, minimize matrix interference and deliver unambiguous peak identification in a single chromatographic run.

Methodology and Instrumentation

IC/MS setup:

• 818 Advanced IC Pump, 819 Detector, 820 Separation Center, 830 Interface, 833 Liquid Handling, 838 Sample Processor
• Agilent 1100 MSD SL equipped with electrospray ionization (ESI), SIM negative mode, fragmentor 70–140 V

IC/ICP-MS setup:

• Same IC modules combined with Agilent 7500 ICP-MS operated in collision or reaction mode

Chromatographic conditions vary per analyte group, using Metrosep A Supp, Agilent Cr Column, Metrosep Anion Dual or Organic Acids columns with tailored eluents (carbonate/bicarbonate, EDTA, oxalic acid) and optimized flow rates (0.4–1.2 mL/min).

Main Results and Discussion

IC–ESI-MS achieved sub-ppb detection (<0.3 ppb) of bromate and perchlorate in drinking water, meeting EPA standards. Simultaneous analysis of acetate, propionate and butyrate in high-salt industrial process water was demonstrated with mass-based quantification. IC–ICP-MS enabled separation and quantitation of Cr(III)/Cr(VI), As(III)/As(V) and selenate/selenite species with detection limits down to 0.1 ppb, facilitating assessment of toxic versus essential forms.

Benefits and Practical Applications

• Enhanced sensitivity and selectivity for regulatory compliance in water and food safety
• Reduced matrix effects through hyphenated detection
• Simultaneous multi-analyte screening and speciation in a single analysis
• Robust identification of trace contaminants for environmental monitoring and industrial QA/QC

Future Trends and Potential Applications

Advances in high-resolution mass spectrometry, microflow IC, and automated sample preparation promise further improvements in detection limits and throughput. Emerging applications include real-time monitoring of disinfection by-products, speciation of novel semiconductors, metabolomics, and comprehensive profiling of organometallic complexes in biopharmaceutical development.

Conclusion

Hyphenated IC–MS and IC–ICP-MS techniques deliver powerful solutions for trace detection and detailed speciation of inorganic and organic analytes. Their integration into analytical workflows supports stringent environmental regulations and industrial quality standards, offering clear advantages in sensitivity, specificity and operational efficiency.

Reference

A. Wille, S. Czyborra, J. Kleimann, "Hyphenated techniques as modern detection systems in ion chromatography," Metrohm AG poster 8.000.6005EN.