A simplified approach for nicotine quantification in electronic cigarette liquids using GC-Orbitrap mass spectrometry

Significance of the topic

The growing use of electronic cigarettes has created a critical need for reliable nicotine quantification methods to protect consumer health and comply with regulatory limits. High-resolution GC-Orbitrap mass spectrometry delivers the sensitivity and specificity necessary to analyze complex e-liquid formulations and ensure adherence to EU Tobacco Products Directive guidelines.

Objectives and Study Overview

This work evaluates the Thermo Scientific Exactive GC Orbitrap system for quantitative analysis of nicotine in commercial e-liquids. Key goals include assessing calibration linearity, mass accuracy, repeatability, and the method’s applicability to both regulated and unregulated products.

Methodology

E-liquid samples with declared nicotine contents of 0, 6, or 12 mg/mL—including shortfill products containing 0 mg/mL—were diluted with LC/MS-grade acetonitrile and spiked with 8-hydroxyquinoline as internal standard. Calibration standards ranged from 46 to 13 792 ng/mL nicotine. Direct liquid split/splitless injection was performed in electron ionization mode. Data were acquired in full-scan at 60 000 resolution, and compounds were identified by retention time, accurate mass (±5 ppm), and ion ratio criteria.

Used Instrumentation

• Exactive GC Orbitrap mass spectrometer
• TRACE 1310 gas chromatograph
• TriPlus RSH autosampler
• Instant Connect split/splitless injector
• TraceGOLD TG-WaxMS capillary column (30 m×0.25 mm×0.25 μm)

Key Results and Discussion

Chromatographic separation yielded clear nicotine and internal standard peaks at 13.77 min. Calibration exhibited excellent linearity (R²=0.9991) across 11 levels with residuals under 4.4%. Mass accuracy remained below 1 ppm for all ions. Repeatability tests on 6 mg/mL samples showed peak area RSDs <4% and concentration RSDs <3%. Analysis of ten commercial e-liquids revealed nicotine levels differing from label claims by –8% to +21%, highlighting variability in unregulated shortfill products.

Benefits and Practical Applications

This GC-Orbitrap approach offers rapid, high-precision nicotine quantitation for regulatory laboratories and industry quality control. The full-scan data supports retrospective screening for additional flavoring agents or impurities without reanalysis.

Future Trends and Potential Applications

Emerging developments may integrate automated multi-component screening workflows and machine learning for data interpretation. Expanding non-targeted analyses could enable comprehensive profiling of e-liquid constituents and support evolving regulatory requirements.

Conclusion

The Exactive GC Orbitrap method provides robust quantitative performance for nicotine in e-liquids, combining rapid calibration, exceptional mass accuracy, and excellent precision. It is a reliable platform for ensuring consumer safety and compliance with regulatory standards.

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