Improved EPA-8330A Analysis with an Agilent InfinityLab Poroshell 120, 1.9 μm Column

Importance of the Topic

The detection and quantification of nitroaromatic and nitramine explosives at trace levels are essential for environmental safety, forensic investigations, and regulatory compliance. Improved chromatographic methods that reduce analysis time, solvent consumption, and sample requirements can drive greater laboratory efficiency and sustainability.

Objectives and Study Overview

This application note describes how Agilent’s superficially porous InfinityLab Poroshell 120, 1.9 µm column enhances the EPA-8330A HPLC/UV protocol for 14 explosive compounds. The main goals were to demonstrate faster separations, lower resource use, and equal or better chromatographic performance compared with a conventional 5 µm column.

Methodology and Instrumentation

An Agilent 1290 Infinity LC system was configured for minimal dead volume and dispersion. Two columns were evaluated:

• Agilent ZORBAX Eclipse Plus C18, 4.6 × 250 mm, 5 µm (traditional)
• Agilent InfinityLab Poroshell 120 EC-C18, 2.1 × 150 mm, 1.9 µm (superficially porous)

The EPA-8330A standard solution containing 14 explosives (e.g., TNT, RDX, HMX) was prepared in acetonitrile. Mobile phases were water (A) and methanol (B), with a linear gradient from 25 % to 35 % B. Methods were geometrically scaled for flow rate and injection volume to match column volumes. The temperature was held at 40 °C, and detection occurred at 254 nm.

Main Results and Discussion

When using the 5 µm column, the separation required 77 minutes at 1.0 mL/min and consumed 77 mL of mobile phase, with a conditional peak capacity of 54 and resolution around 2.0. Transferring to the 1.9 µm Poroshell column yielded:

• Run time reduced to 23 minutes (3× faster)
• Mobile phase consumption of 9.2 mL (88 % less)
• Sample volume downscaled by 88 %
• Conditional peak capacity increased to 79 (46 % higher)
• Resolution improved to approximately 2.8

The similar bonded-phase chemistry enabled seamless method transfer without altering selectivity. Although backpressure rose from ~240 bar to ~1132 bar, modern UHPLC systems accommodate these conditions.

Benefits and Practical Applications

The Poroshell 120, 1.9 µm column provides significant advantages for routine explosive residue screening:

• Higher throughput—more samples per day
• Lower solvent and sample usage—cost and waste reduction
• Enhanced sensitivity and peak capacity—improved quantitation

These gains support laboratories in environmental monitoring, forensic chemistry, and quality assurance workflows.

Future Trends and Opportunities

Ongoing development of superficially porous particle technology aims to further decrease particle diameter while controlling backpressure. Integration with mass spectrometry detection and automated sample preparation will expand applicability. Green chromatography initiatives may drive wider adoption of low-volume, high-efficiency columns.

Conclusion

The Agilent InfinityLab Poroshell 120, 1.9 µm column successfully streamlines the EPA-8330A analysis of explosive residues by delivering faster run times, dramatic solvent and sample savings, and superior chromatographic performance compared to a traditional 5 µm column. Method transfer is straightforward due to matched selectivity, making this approach a valuable upgrade for analytical laboratories.

References

1. A. Gratzfield-Hugsen, E. Naegele. Maximizing efficiency using Agilent Poroshell 120 Columns. Agilent Technologies Application Note 5990-5602EN (2016).
2. V. R. Meyer. Practical High Performance Liquid Chromatography, 4th Edition. Wiley (2004).
3. Agilent Technologies. Transfer of Methods between Poroshell 120 EC-C18 and ZORBAX Eclipse Plus C18 Columns. Application Note 5990-6588EN (2011).