Automated Sequencing of Elemental Speciation Methods Using HPLC-ICP-MS with a Quick Change Valve Head

Significance of the Topic

Elemental speciation provides insight into the chemical forms that determine the mobility, bioavailability and toxicity of trace elements in food, environmental and consumer products. Automated high-throughput speciation supports risk assessment and ensures compliance with regulatory limits for arsenic, mercury, bromine and iodine.

Objectives and Study Overview

This study assesses an HPLC-ICP-MS platform equipped with a Quick Change valve head to enable unattended, sequential speciation of inorganic arsenic (As(III) and As(V)), methylmercury and halogen species (Br–, BrO3–, I–, IO3–). The goal is to demonstrate automated switching between chromatographic methods within a single run.

Methodology and Instrumentation

Stock solutions of target species were prepared and diluted into three calibration levels. An Agilent 1260 Infinity II LC system with a quaternary pump and four-position Quick Change column selector valve head was coupled via the LC connection kit to an Agilent 7900 ICP-MS. Three optimized chromatographic methods—each using a dedicated column and mobile phase—were scheduled in a programmable sequence, with a deionized-water wash step between methods to minimize carryover.

Main Results and Discussion

All analytes exhibited excellent calibration linearity (R²>0.9995) over three days of operation. Intraday repeatability (RSDr) was ≤8% and interday reproducibility (RSDiR) ≤10%. Recoveries ranged from 90% to 110%. Carryover was reduced below 2% after wash steps. A full sequence of 43 injections completed within 5.5 hours, demonstrating stable retention times and peak areas regardless of method order.

Benefits and Practical Applications

• High throughput via unattended multi-method sequencing
• Reduced manual intervention, time and reagent use
• Capability to run up to eight speciation methods in one sequence
• Consistent data quality for regulatory compliance in food and environmental laboratories

Future Trends and Potential Applications

Expansion to larger valve arrays and a greater number of mobile phases will support broader multi-element speciation. Coupling with tandem mass spectrometry and real-time data analytics can enhance sensitivity and specificity. Full integration into automated laboratory workflows promises higher throughput for routine monitoring and on-site analysis.

Conclusion

Implementing an HPLC-ICP-MS system with Quick Change valve head streamlines multi-element speciation by automating column and solvent switching, delivering robust performance, operational flexibility and improved laboratory productivity.

References

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