Maximizing Efficiency Using Agilent InfinityLab Poroshell 120 Columns

Importance of the Topic

High-efficiency liquid chromatography is central to modern analytical chemistry workflows in pharmaceutical, environmental, food and chemical laboratories. Superficially porous (core-shell) column technology balances high separation efficiency with lower system backpressure. This enables rapid analyses, shorter cycle times and robust method performance without the need for ultra-high-pressure instrumentation.

Objectives and Study Overview

• Assess the separation efficiency of a single Agilent InfinityLab Poroshell 120 column (4.6×150 mm, 2.7 µm).
• Evaluate performance gains from coupling three identical columns under isocratic and gradient conditions.
• Compare pressure limits, plate numbers and peak capacity to a sub-2 µm particle column.
• Examine retention time precision, signal-to-noise for trace impurities and volume loading capacity.

Methodology and Instrumentation

All experiments employed an Agilent 1290 Infinity binary pump system with autosampler, thermostatted column compartment and diode-array detector operating with ChemStation B.04.02 software. Columns tested included:

• Agilent InfinityLab Poroshell 120 SB-C18, 4.6×150 mm, 2.7 µm.
• Agilent ZORBAX Rapid Resolution HT SB-C18, 4.6×150 mm, 1.8 µm (reference).

Coupling of three Poroshell columns was achieved via 90 mm×0.12 mm stainless steel capillaries. Mobile phases were aqueous and acetonitrile mixtures with and without trifluoroacetic acid modifier. Flow rates ranged from 1.0 to 1.8 mL/min and column temperatures from 30 °C to 60 °C. Samples included small aromatic probes, a ketone mixture, thiourea marker and trace pharmaceutical impurities.

Results and Discussion

• Single Poroshell column delivered ~35 000 plates for toluene at 1.5 mL/min under isocratic conditions.
• Three-column coupling achieved plate counts of ~83 000 at 1 mL/min and ~115 000 at 1.8 mL/min, all within 5 minutes run time and under 600 bar backpressure.
• Retention time precision (RSD) was better than 0.04 % for gradient and isocratic modes; area precision <0.7 % RSD.
• Peak capacity increased by ~30 % (133 vs 101) compared with the 1.8 µm column under identical gradient conditions.
• Signal-to-noise ratios for low-level impurities (0.02–0.03 %) were equivalent or slightly improved on Poroshell columns.
• Volume loading tests up to 20 µg injection showed similar capacity and slightly narrower peak widths for the Poroshell phase.

Benefits and Practical Applications

• High throughput separations in routine QA/QC without specialized UHPLC equipment.
• Lower system wear and solvent consumption due to reduced operating pressures.
• Enhanced peak capacity and resolution for complex mixtures.
• Reliable retention time and quantitative precision supports method validation in regulated environments.

Future Trends and Potential Applications

Advances in core-shell particle design and coupling strategies will further push throughput limits. Integration of superficially porous columns into multi-dimensional LC workflows and miniaturized systems may open new avenues in proteomics, metabolomics and high-throughput screening. Continuous improvements in column chemistries will extend applications to highly demanding separations in life-science and industrial analytics.

Conclusion

Agilent InfinityLab Poroshell 120 columns offer a compelling alternative to sub-2 µm columns by delivering up to 115 000 theoretical plates in under 5 minutes with manageable backpressure. Coupling three columns multiplies efficiency without sacrificing robustness and reproducibility. This technology enhances laboratory productivity across diverse analytical applications.

References

• Cunliffe JM, Maloney TD. Fused-core particle technology as an alternative to sub-2-µm particles to achieve high separation efficiency with low backpressure. J Sep Sci. 2007;30(19):3104–3109.
• Gritti F, et al. Comparison between the efficiencies of columns packed with fully and partially porous C18-bonded silica materials. J Chromatogr A. 2007;1157(1-2):289–303.