The Determination of Flavors in E-Liquids Using Purge and Trap Concentration

Significance of the topic

Purge and trap microextraction coupled to gas chromatography mass spectrometry is a sensitive approach to profile volatile flavor compounds in e-liquid matrices. Its exhaustive sampling provides reproducible detection of esters and other aroma components critical to product consistency and safety.

Objectives and Study Overview

This study aimed to evaluate flavor compound profiles in five vape liquids and assess the impact of nicotine concentration on aroma composition. Multiple replicates were analyzed to determine reproducibility and relative abundance of key volatile species.

Methodology and Instrumentation

The workflow employed water dilution of e-liquids followed by purge and trap concentration and GC-MS analysis. The main instruments and conditions included:

• Purge and Trap Concentrator: EST Analytical Evolution with Vocarb 3000 trap, purge time 11 min, desorb at 250 °C
• Autosampler: EST Analytical Centurion WS in water mode, 5 mL sample volume, syringe rinse cycles
• GC-MS: Split mode inlet at 220 °C, Rxi-624Sil MS column, oven ramp from 45 °C to 220 °C, helium carrier, MS scan m/z 35–300

Key Results and Discussion

Each flavor exhibited a distinct ester profile dominated by ethyl acetate, propanoic acid ethyl ester and butanoic acid derivatives with relative standard deviations below 11%. Flavors such as cookie and tobacco showed simple four-component patterns, while strawberry cereal contained up to ten esters and terpenes. Nicotine levels influenced compound responses: higher nicotine reduced signals of certain esters, indicating matrix effects on volatile release.

Benefits and Practical Applications

• High sensitivity detection of low-abundance esters ensures flavor quality control
• Exhaustive sampling yields excellent reproducibility for regulatory compliance
• Matrix impact assessment guides formulation adjustments in e-liquids

Future Trends and Opportunities

Advances in trap materials and automated sampling will further lower detection limits and expand compound coverage. Coupling with high-resolution MS and chemometric analysis can enable comprehensive aroma fingerprinting in diverse aerosol products.

Conclusion

Purge and trap GC-MS provides a robust platform for volatile analysis in vape solutions. The technique offers reproducible quantification of flavor esters and reveals nicotine-dependent matrix interactions affecting sensory attributes.

Reference

• Anne Jurek. Solid Phase Micro Extraction of Flavor Compounds in Beer. EST Analytical Application Note.
• onVaping. Beginners Guide to Vaping Chapter 6 E Juice and You. onVaping.com; accessed 2023.