Agilent ZORBAX - A proven and reliable portfolio of totally porous HPLC columns

Importance of the Topic

The selection of an appropriate HPLC column is critical for achieving optimal separation efficiency, sensitivity and robustness across diverse analytical challenges. Totally porous particle columns offer enhanced retention, higher loading capacity and greater solvent compatibility, supporting method development from ultra-high-pressure LC (UHPLC) to preparative scale separations.

Study Objectives and Overview

This application note presents the Agilent ZORBAX family of totally porous HPLC columns and highlights their performance characteristics. The primary goals are to compare key chemistries, particle and pore sizes, operational limits and to provide guidance on choosing the best column for general-purpose, specialized and high-speed applications.

Methodology and Instrumentation

The portfolio was evaluated under standard reversed-phase conditions using Agilent Infinity II LC systems. Column varieties—featuring C18, C8, phenyl-hexyl, cyano and polymeric C18 chemistries—were tested across particle sizes (1.8–7 µm), pore diameters (95–120 Å), pH ranges (0.8–11), and temperatures (60–90 °C). Performance metrics included retention factors, peak shape, plate count and solvent resistance.

Key Results and Discussion

• The 1.8 µm ZORBAX RRHD C18 column delivered the highest efficiency under UHPLC pressures up to 1200 bar, making it ideal for fast, high-resolution separations.
• C8 variants showed lower hydrophobic retention yet maintained sharp peaks, giving an alternative selectivity for less nonpolar analytes.
• Phenyl-hexyl and phenyl columns offered enhanced π-π interactions, improving aromatic compound resolution when using methanol-based mobile phases.
• Cyano (CN) columns demonstrated excellent peak shape for polar and mid-polar compounds in reversed-phase mode.
• Polymeric C18 and HILIC columns expanded the portfolio to cover polyaromatic hydrocarbons and highly polar analytes under aqueous-rich or HILIC conditions.

Benefits and Practical Applications

• Seamless method scale-up from analytical UHPLC to preparative LC.
• Broad pH and temperature stability for challenging sample matrices.
• Robust performance in gradient and isocratic modes with diverse solvent systems.
• Alternative selectivities available for complex mixtures, including lipophilic, polar and aromatic targets.
• Endcapped and high-carbon columns ensure consistent retention and reduced bleed in LC-MS workflows.

Future Trends and Opportunities

Advances in superficially porous (“core-shell”) particle technology will continue to bridge the gap between efficiency and backpressure, enabling faster analyses on standard HPLC hardware. Integration with high-throughput LC systems and automated sample preparation will streamline workflows in pharmaceutical, environmental and food-safety testing. Emerging chemistries and column formats are expected to further enhance selectivity for large biomolecules and highly polar compounds.

Conclusion

The Agilent ZORBAX line of totally porous HPLC columns provides a versatile suite of chemistries and particle constructs to optimize separation quality across a wide range of analytical and preparative applications. By matching column selection to sample properties and system capabilities, laboratories can achieve faster runtimes, improved resolution and greater method robustness.

Instrumentation Used

• Agilent 1290 Infinity II UHPLC system (up to 1200 bar).
• Agilent 1260 Infinity II Prime LC and standard 1260 Infinity II LC (up to 600 bar).
• Preparative LC configurations for scale-up applications.

References

• Agilent Technologies. Agilent ZORBAX Totally Porous HPLC Columns. Publication 5994-2212EN (July 2020).