Recently, synthetic cannabinoids (SCs) have emerged as new psychoactive substances (NPS) and have been frequently added to e-liquids, leading to their abuse. In order to detect SCs in e-liquids quickly and accurately, a thermal-assisted carbon fiber ionization mass spectrometry technique has been developed. The introduction of a heat source helps to reduce the matrix effects. The results indicate that the ratio of the slope of the matrix curve (e-liquids matrix) and the standard curve (methanol solution) for SCs analysis is close to 1, indicating a minimized matrix effect of this method. Furthermore, this method exhibits good quantitative ability when applied to real samples. It does not require sample pretreatment and is sensitive enough to directly quantify SCs in e-liquids. Our method is characterized by the ability to achieve rapid and direct quantitative analysis with minimized matrix effects. It provides a rapid and simple method for analyzing SCs in e-liquids.

Sale of electronic cigarette (e-cigarette) products has exponentially increased in the past decade, which raise concerns about its safety. This updated review provides the available toxicology profile of e-cigarettes, summarizing evidence from in vitro and in vivo studies. Data regarding which components in e-liquids exhibit potential toxicities are inconsistent. Some studies have reported that nicotine plays a significant role in inducing adverse outcomes and that solvents alone do not induce any adverse effects. However, other studies have suggested that nicotine is not associated with any adverse outcomes, whereas solvents and flavorings are the key components to elicit considerable deleterious effects on cells or animals. In addition, most of the studies that have compared the toxicity of e-cigarettes with tobacco cigarettes have suggested that e-cigarettes are less toxic than tobacco cigarettes. Nevertheless, scientific evidence regarding the toxicity profile of e-cigarette is insufficient owing to the lack of a standardized research approach. In the future, scientific toxicology data derived from standardized testing protocols including nicotine, ingredients analysis, the various e-cigarette devices made from different materials are urgently needed for thorough toxicology assessment. This review aims to update the toxicity profiles, identify knowledge gaps, and outline future directions for e-cigarettes research, which would greatly benefit public health professionals.