New Review Highlights Chromatographic Methods for E-Cigarette Analysis

Researchers from the University of Maribor in Maribor, Slovenia reviewed various techniques to determine e-liquid and aerosol composition in electronic cigarettes (ECs). The study highlighted liquid chromatography and gas chromatography, as well as the instances where each technique is most effective. Their findings were published in the Journal of Chromatography A (1).

Different electronic cigarettes on light blue background, closeup | Image Credit: © New Africa - stock.adobe.com

Smoking technology has evolved constantly since the practice’s origins, dating back to South American civilization approximately 7000 years ago (2). The latest innovation in smoking technology is electronic cigarettes (ECs), which can refer to the devices themselves, the e-liquid contained within, and the aerosols produced. In 2024, 1.6 million students in the United States were found to use e-cigarettes, including 410,000 middle school students and 1.21 million high school students (3). No e-cigarettes have been approved by the U.S. Food and Drug Administration (FDA) as a smoking cessation aid (4).

There is typically a lack of detail on the chemical composition of e-liquids on packaging. Labels only specify the volume or mass ratio of base compounds, which include organic diluents. However, consumers can also mix their own e-liquids, causing ratios different from commercially available e-liquids. E-liquids can also contain compounds like cannabinoids, nicotine, and nicotine salts, which have their own regulations (1).

In this article, the scientists reviewed the analytical techniques used to qualitatively and quantitatively determine e-liquid and aerosol compounds stemming from ECs, including descriptions of the methods used for aerosol collection. Additionally, the researchers explored the broader context of modern ECs, including design, regulatory framework, and potential health impacts. To ensure their analyses were thorough and up-to-date, relevant studies were identified using extensive database searches, covering research from the mid-2010s with emphasis on findings from the past five years to reflect the latest advancements and emerging concerns in the field.

The various analytical techniques used to determine the composition of e-liquids and their aerosols each come with their own advantages and disadvantages. Liquid chromatography (LC) and especially gas chromatography (GC) coupled with various detectors are the primary analytical techniques for analyzing e-liquids and their aerosols. These techniques are complementary, with GC being ideal for volatile compounds and LC applied for determining more complex non-volatile polar compounds. Given complex e-liquid matrices, these techniques typically require extensive method development, including sample preparation, the use of different chromatography columns, and the optimization of experimental setups to efficiently separate the diverse array of compounds present in e-liquids and aerosols.

Analyzing e-liquid aerosols can also be challenging, as they must first be generated using vaping machines, which are rare. As a result, researchers must create alternative in-house methods that are less likely to ensure reproducible vaping patterns. The scientists believe future research should focus on refining aerosol generation and standardized vaping patterns, which would improve comparisons between studies.

There are various complexities to understand with e-liquid and aerosol composition, making the need for continued analytical oversight a notable one. The latter concern can also ensure reliable data for regulatory and public health interventions, aiming to mitigate the health impacts associated with EC use.

References

(1) Rantaša, M.; Majer, D.; Finšgar, M. A Review of Analytical Techniques for the Determination of E-Liquid and Electronic Cigarette Aerosol Composition. J. Chromatogr. A 2025, 1748, 465859. DOI: 10.1016/j.chroma.2025.465859

(2) Berenguer, C.; Pereira, J. A. M.; Câmara, J. S. Fingerprinting the Volatile Profile of Traditional Tobacco and E-Cigarettes: A Comparative Study. Microchem. J. 2021, 166, 106196. DOI: 10.1016/j.microc.2021.106196

(3) E-Cigarette Use Among Youth. CDC 2025. https://www.cdc.gov/tobacco/e-cigarettes/youth.html (accessed 2025-4-7)

(4) E-Cigarettes (Vapes). CDC 2025. https://www.cdc.gov/tobacco/e-cigarettes/index.html (accessed 2025-4-7)