Analysis of Nineteen Explosives Using a Hypersil GOLD aQ HPLC Column

Importance of the Topic

Accurate and rapid analysis of explosive compounds is critical for environmental monitoring, forensic investigations, and industrial safety. Regulatory methods such as EPA Method 8330 require reliable separation and quantification of nitroaromatics, nitroamines, nitrate esters and peroxides. High-performance liquid chromatography (HPLC) with advanced stationary phases offers the sensitivity and reproducibility needed to meet these demands.

Study Objectives and Overview

This application note evaluates the performance of a Thermo Scientific Hypersil GOLD aQ HPLC column for the separation of nineteen explosives, including compounds listed in EPA Method 8330. The primary goals were to develop a robust, isocratic method compatible with both UV and mass spectrometric detection, and to demonstrate baseline resolution of structurally related analytes within a short analysis time.

Methodology and Instrumentation

• Instrumentation: Thermo Scientific Accela HPLC/UHPLC system
• Column: Hypersil GOLD aQ, 3 µm, 250 × 4.6 mm
• Mobile Phase (isocratic): 50:45:5 (v/v/v) water + 0.1% formic acid / methanol + 0.1% formic acid / acetonitrile + 0.1% formic acid
• Flow Rate: 1.0 mL/min
• Column Temperature: 35 °C
• Injection Volume: 25 µL
• UV Detection: dual wavelengths at 245 nm and 215 nm
• Reagents: HPLC-grade water, acetonitrile, methanol
• Sample Vials: 2 mL clear vials with bonded PTFE-silicone caps

Main Results and Discussion

The method achieved complete separation of nineteen explosives in under 25 minutes. At 245 nm, all peaks were well resolved with retention times ranging from 3.66 min (2,6-diamino-4-nitrotoluene) to 24.44 min (HNS). Lowering the detection wavelength to 215 nm enhanced response for low-UV-absorbing analytes such as EGDN and nitroglycerin, though baseline noise increased. Precision testing (six replicate injections) yielded retention time RSD values below 1.3% for all compounds, demonstrating excellent reproducibility. The increased noise at 215 nm suggests that coupling with mass spectrometry would improve sensitivity and specificity for trace-level analysis.

Benefits and Practical Applications

• Rapid throughput: Full separation in less than 25 minutes supports high sample volumes.
• Wide applicability: Effective for nitroaromatics, nitroamines, nitrate esters, and peroxides.
• Flexibility: Compatible with UV and MS detection, enabling both routine screening and trace-level confirmation.
• Robustness: Low RSD values ensure reliable quantitation in quality control, environmental monitoring, or forensic labs.

Future Trends and Opportunities

Advances in stationary-phase chemistry and smaller particle sizes will drive even faster separations and greater peak capacity. Greener solvent systems and microflow HPLC could reduce solvent consumption and waste. Integration with high-resolution mass spectrometry and automated data processing will expand applications in environmental forensics, defense, and industrial process monitoring. Emerging ion-mobility techniques may add a further dimension of separation for complex explosive mixtures.

Conclusion

The Hypersil GOLD aQ column provides a reliable, fast, and versatile platform for the analysis of a broad range of explosive compounds. Its compatibility with both UV and MS detection, combined with excellent precision and resolution, makes it well suited for regulatory compliance, forensic investigations, and routine laboratory workflows.

References

None cited explicitly in this application note.