Advantages of CORTECS C18 2.7 μm and XBridge BEH Phenyl XP 2.5 μm Columns for the Analysis of a Comprehensive Panel of Pain Management Drugs for Forensic Toxicology

Significance of the Topic

Forensic toxicology laboratories require rapid, robust methods to screen a broad panel of pain management drugs including opioids, benzodiazepines and stimulants. Efficient chromatographic separation and low system backpressure are critical to achieve high throughput without upgrading existing HPLC infrastructure.

Objectives and Study Overview

This study evaluates two Waters reversed-phase columns—CORTECS C18 2.7 μm and XBridge BEH Phenyl X P 2.5 μm—alongside a competitive biphenyl core-shell column for the simultaneous analysis of 35 commonly abused pain management compounds. Key performance metrics include resolution of isobaric pairs, peak shape, analysis time and operating pressure.

Methodology

Stock solutions of analytes were prepared in methanol and diluted in 5% acetonitrile/0.1% formic acid. Separations employed a 3.0 × 50 mm column at 30 °C with a 5-minute gradient (95→40% aqueous mobile phase) at 0.6 mL/min and 10 μL injection volume.

Applied Instrumentation

• LC System: Waters ACQUITY UPLC I-Class with fixed-loop autosampler and column manager
• Columns: CORTECS C18 2.7 μm (p/n 186007370), XBridge BEH Phenyl X P 2.5 μm (p/n 186006069), competitor biphenyl core-shell 2.6 μm
• MS Detector: Waters Xevo TQD in ESI positive mode, optimized cone and collision voltages
• Data Software: MassLynx v4.1

Main Results and Discussion

All 35 compounds eluted within 4 minutes with symmetric peaks. The CORTECS C18 column delivered the lowest average peak width (2.52 s) and the lowest backpressure (~2200 psi), outperforming smaller-particle alternatives. Baseline resolution was achieved for critical isobaric pairs such as morphine/hydromorphone and codeine/hydrocodone on all columns. Separation of stimulants methamphetamine and phentermine occurred only on the C18 and phenyl columns, preventing potential mass spectral cross talk.

Benefits and Practical Applications

• High throughput: complete panel analysis in under 4 minutes per injection
• Compatibility: low operating pressures suit standard HPLC systems without hardware changes
• Enhanced selectivity: phenyl functionality improves retention of polar opiates and reduces matrix effects

Future Trends and Opportunities

• Development of novel stationary phases combining solid-core efficiency with tailored surface chemistries for expanded analyte coverage
• Integration of ultra-high-throughput sampling and automation to further accelerate forensic workflows
• Coupling with high-resolution or ion mobility mass spectrometry to enhance specificity and lower detection limits

Conclusion

Both CORTECS C18 2.7 μm and XBridge BEH Phenyl X P 2.5 μm columns enable rapid, high-resolution analysis of a comprehensive forensic toxicology panel at pressures compatible with standard HPLC systems. Laboratories can select between the high efficiency of solid-core C18 or the enhanced selectivity of phenyl chemistry based on specific analytical needs.