40 mL of Electronic Cigarette Vapor Collected on a Thermal Desorption Tube and Analyzed on Rtx®-VMS

Importance of Topic

This study addresses the detailed chemical profiling of electronic cigarette vapor, a rapidly growing area of interest in public health and regulatory science. Characterizing volatile and semi-volatile compounds released by e-cigarettes is critical for understanding potential toxicological risks, guiding product standards, and informing end users and policymakers about inhalation exposures.

Objectives and Study Overview

The primary goal was to identify and quantify a broad range of gaseous and vapor-phase constituents emitted during a single 40 mL puff from an electronic cigarette. A thermal desorption tube collected the sample, which was subsequently analyzed using a capillary gas chromatography–mass spectrometry (GC-MS) method on an Rtx®-VMS column. The work provides a retention-time-resolved list of detected compounds across four chromatographic regions.

Applied Methodology and Instrumentation

The vapor was drawn directly into a thermal desorption tube and introduced onto a 30 m × 0.25 mm ID, 1.40 µm Rtx®-VMS GC column. The oven program ramped from 35 °C (1 min hold) to 250 °C at 11 °C/min (4 min hold). Helium served as carrier gas (2.0 mL/min constant flow). Mass spectrometric detection employed electron ionization (70 eV) in full-scan mode (m/z 15–550).

Main Results and Discussion

The analysis revealed 82 chromatographic peaks categorized into four retention-time windows, each representing a distinctive chemical class:

• Red region (0.7–3.2 min): permanent gases (nitrogen, oxygen, CO₂), light volatiles (formaldehyde, acetaldehyde, acrolein, methanol, ethanol) and solvents (methylene chloride, acetonitrile).
• Orange region (3.5–7.5 min): small aromatics and aliphatics (benzene, toluene, hexane) and siloxane by-products (trimethylsilanol, hexamethylcyclotrisiloxane).
• Green region (7.7–12.3 min): polyfunctional compounds (propylene glycol, glycerin, acetylpyrazine), xylenes and styrene.
• Blue region (12.7–20.5 min): higher siloxanes (cyclopentasiloxane, cyclohexasiloxane), nicotine, alkaloid derivatives (myosmine, nicotyrine) and various unidentified late-eluting species.

Several hazardous compounds—formaldehyde, acrolein, benzene and toluene—were detected with high match quality. Concentrations of certain light gases closely matched laboratory blanks, indicating background contributions.

Benefits and Practical Applications

The described method provides a rapid, sensitive workflow for comprehensive vapor profiling. It can be applied in product development, quality control, regulatory compliance testing and toxicological risk assessment. The ability to separate and identify trace impurities improves understanding of user exposure and supports standardized safety evaluations.

Future Trends and Potential Applications

Advances may include real-time mass spectrometric monitoring, automated data analysis for complex mixtures and coupling with high-resolution or tandem MS for structural elucidation of unidentified compounds. Trends point toward harmonized protocols across laboratories, miniaturized sampling devices and integration with toxicokinetic modeling to better predict health outcomes.

Conclusion

This study demonstrates the utility of thermal desorption–GC-MS on an Rtx®-VMS column to deliver a detailed chemical fingerprint of e-cigarette emissions. The approach identifies both common and proprietary constituents, informing risk assessments and guiding regulatory standards.

References

• Rtx®-VMS Column, 30 m × 0.25 mm ID, 1.40 µm (Restek, cat. #19915).
• Agilent 7890B GC coupled with 5977A MSD; Markes UNITY™ thermal desorption system.