Chiral separation of methamphetamine and amphetamine on an Agilent InfinityLab Poroshell 120 Chiral-V column with detection by LC/MS

Importance of the topic

Chiral analysis of methamphetamine and amphetamine is essential for accurate forensic, clinical, and pharmaceutical assessments. The two enantiomers exhibit distinct biological activities and regulatory classifications. Reliable baseline separation ensures unambiguous identification, quantification, and compliance with legal requirements.

Study objectives and overview

This work aimed to demonstrate rapid, high-resolution chiral separation of racemic methamphetamine and amphetamine using an Agilent InfinityLab Poroshell 120 Chiral-V 2.1 × 150 mm, 2.7 µm column coupled to LC/MS. Key goals included achieving baseline resolution (Rs ≥ 1.9) in under 5 minutes and evaluating the effect of column temperature on retention and selectivity.

Methodology and instrumentation

The analysis employed:

• An Agilent 1290 Infinity LC system with reduced dispersion configuration
• An Agilent 6460 triple quadrupole MS operated in positive ESI (Jet Stream) mode
• Column: InfinityLab Poroshell 120 Chiral-V, 2.1 × 150 mm, 2.7 µm
• Mobile phase: methanol / 0.1 % acetic acid / 0.02 % NH₄OH (1 000 : 1 : 0.2, isocratic)
• Flow rate: 0.25 mL/min; column temperature: 20 °C, 30 °C, 40 °C; injection volume: 0.2 µL
• Analytes: 5 µg/mL racemic methamphetamine and amphetamine in mobile phase
• MRM transitions: methamphetamine 150.1 → 91.1 / 65.1; amphetamine 136.1 → 119 / 91

Main results and discussion

At 20 °C and 181 bar, the four enantiomeric peaks eluted between 2.39 and 3.94 min with resolutions of 2.1, 2.1, and 1.8. Increasing temperature reduced retention times and backpressure (164 bar at 30 °C; 149 bar at 40 °C), while selectivity between pairs remained above 1.5. The method delivered baseline separation within 5 minutes, enabling precise integration and quantitation of all four enantiomers.

Benefits and practical applications

The combination of superficially porous particle technology and direct MS detection offers:

• High separation efficiency with low system backpressure
• Fast cycle times (< 5 min) for high throughput
• Elimination of derivatization steps
• Enhanced selectivity and sensitivity for trace-level enantiomer quantitation

This approach is suitable for forensic toxicology, clinical monitoring, anti-doping, and pharmaceutical quality control.

Future trends and applications

Ongoing developments may include further particle size reduction, ultrafast chiral screening methods, integration with high-resolution MS, and automated fraction collection for preparative applications. Expanding the methodology to other chiral drug classes will broaden its utility.

Conclusion

The Agilent InfinityLab Poroshell 120 Chiral-V column, paired with LC/MS, achieved rapid baseline separation of methamphetamine and amphetamine enantiomers with high resolution and minimal backpressure. The method is robust, sensitive, and readily implementable in routine forensic and clinical laboratories.

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