Inorganic Speciation Columns and Supplies

Significance of the Topic

Understanding the chemical forms of inorganic elements is critical for assessing their toxicity, bioavailability, and regulatory compliance. Total metal concentrations alone may obscure the true risk posed by more toxic species such as arsenite (As III) and arsenate (As V). Accurate speciation analysis supports food safety, environmental monitoring, and public health initiatives.

Objectives and Study Overview

This work presents an integrated solution for inorganic speciation, combining high-performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). It aims to demonstrate reproducible separation of key metal species in diverse matrices—water, juices, urine, food, and consumer products—and to showcase the corresponding column chemistries and interface supplies.

Methodology

Chromatographic separations employ anion exchange and reversed-phase columns optimized for target species. Samples are introduced via specialized LC interfaces and quantified by ICP-MS using isotope dilution or external calibration. Rigorous blank evaluations confirm absence of contamination down to low-ppt levels. Calibration curves for arsenic species ensure precise quantitation across environmental and food sample types.

Used Instrumentation

• Agilent 1290 Infinity LC System, featuring sub-2 µm and superficially porous Poroshell 120 columns
• Agilent 7900 Series ICP-MS with ORS4 reaction cell
• ZORBAX Extend-C18 and Bio WAX anion exchange columns
• Comprehensive LC and GC interface kits for robust coupling

Main Results and Discussion

Arsenic speciation in preparation blanks confirmed undetectable levels of As species. A 50 ng/L mixed standard produced sharp, well-resolved peaks for DMA, As(III), AB, MMA, and As(V). Analysis of four commercial apple juice samples showed all species well below EPA limits, with chromatograms scaled uniformly to highlight relative concentrations. Mercury speciation under gradient conditions achieved complete separation of Hg2+, MeHg+, EtHg+, and PhHg+ in under three minutes, with recoveries between 94 % and 101 % in certified fish reference materials.

Practical Benefits and Applications

• High sensitivity and specificity enable low-level speciation in complex matrices
• Reproducible separations reduce rework and streamline QA/QC workflows
• Flexible column chemistries support a broad range of applications—from drinking water to toy safety
• Comprehensive interface kits simplify setup for LC-ICP-MS and GC-ICP-MS coupling

Future Trends and Opportunities

Advances in column technology—such as sub-2 µm particles and superficially porous media—will shorten analysis times and enhance resolution. Integration of automated sample preparation, expanded handbooks of hyphenated ICP-MS methods, and cloud-based data analysis tools will further accelerate speciation workflows and broaden accessibility for regulatory and research laboratories.

Conclusion

The combination of specialized HPLC columns, robust interface supplies, and high-performance ICP-MS detection offers a turnkey solution for elemental speciation. This integrated approach delivers accurate, reproducible, and efficient analyses across multiple sample types, ensuring compliance with health and safety standards.

References

• Agilent Technologies. Arsenic Speciation Analysis Handbook, Publication G3154-90011, 2014.
• Agilent Technologies. Application Note 5991-0622EN: Arsenic Speciation in Fruit Juices.
• Agilent Technologies. Application Note 5989-8399EN: Arsenic Speciation in Urine and Food.
• Agilent Technologies. Application Note 5990-9366EN: Chromium Speciation in Drinking Water.
• Agilent Technologies. Application Note 5991-0066EN: Mercury Speciation in Food Samples.
• Agilent Technologies. Application Note 5991-2878EN: Chromium Speciation in Toys (EN71-3).
• Agilent Technologies. Handbook of Hyphenated ICP-MS Methods.