气相色谱法测定电子烟烟液及气溶胶中双乙酰和乙酰丙酰

建立气相色谱法氢火焰离子化检测器测定电子烟烟液和气溶胶中双乙酰和乙酰丙酰含量的方法。样品以20 mL乙醇为萃取剂,涡旋振荡萃取10 min,采用气相色谱外标法进行定量分析。双乙酰和乙酰丙酰质量浓度在0.5~50 μg/mL范围内与色谱峰面积呈良好的线性关系,相关系数分别为0.999 6、0.999 4,方法检出限分别为0.044、0.052 μg/mL。烟液中双乙酰和乙酰丙酰测定结果的相对标准偏差为2.5%~4.3%(n=6),样品加标回收率为95.0%~102.5%;气溶胶中双乙酰和乙酰丙酰测定结果的相对标准偏差为3.1%~4.6%(n=6),样品加标回收率为92.7%~102.3%。气溶胶中双乙酰和乙酰丙酰理论浓度与实测浓度具有较强的相关性(对于双乙酰r~2=0.990 1,对于乙酰丙酰r~2=0.994 7),说明双乙酰、乙酰丙酰烟液通过雾化直接转移至气溶胶中。该方法准确度高,重现性好,检出限低,可满足电子烟样品的检测需求。     

Quantification of selected aroma compounds in e-cigarette products and toxicity evaluation in HUVEC/Tert2 cells

During recent years, the number of consumers using so-called e-cigarettes, which are electrical devices to aerosolize a liquid consisting of propylene glycol, glycerol, optional nicotine and flavoring chemicals, has been increasing. Aromas vary from common flavors such as mint to more unusual flavors such as buttermilk or pepperoni pizza. Consumers today can buy e-concentrates that consist of propylene glycol and aroma to blend their own desired flavor at home. Little is known about the composition and concentration of various aroma molecules in the different e-liquids and e-concentrates. In addition, the process of EU-wide regulation is still ongoing. The aim of this research study was to identify and quantify possible undesirable aroma compounds in e-liquids and e-concentrates. Flavoring chemicals such as estragole, benzaldehyde and cinnamaldehyde were quantified. The measurements were carried out on a GC–MS system. The results show the presence of highly concentrated flavoring compounds and limonene oxide in lemon-flavored e-concentrates. In the final step, samples and single-aroma standards were tested for their toxicity to HUVEC/Tert2 cells, where some single-flavoring chemicals such as cinnamic aldehyde revealed significant toxic effects.     

Nicotine-related impurities in e-cigarette cartridges and refill e-liquids

The nicotine used in e-cigarettes and refill e-liquids is extracted from tobacco, and its purity can vary depending upon manufacturer and grade. The US and European Pharmacopoeias make recommendations for the purity of nicotine intended for pharmaceuticals; however, there is no official purity recommendation for nicotine used in e-cigarettes. To date, there are few published reports on nicotine-related impurities in e-cigarettes and refill e-liquids. The objective of this work was to develop a sensitive, selective, and robust analytical method for the quantitation of nicotine-related impurities in e-vapor products and to evaluate the nicotine-related impurities in a variety of commercial e-cigarette cartridges (n?=?10) and refill e-liquids (n?=?10). Nicotine-N-oxide, nornicotine, mysomine, and cotinine were observed to increase with time during stability studies. This method was also applied to estimate the transfer efficiency of nicotine-related impurities to the aerosol. Most of the impurities were observed to transfer efficiently. However, nicotine-N-oxides showed low transfer efficiency and demonstrated thermal degradation. This selective and sensitive method is suitable to provide quantitative data for risk assessments and for use in e-cigarette product and refill e-liquid stability studies as one of the stability-indicating measures.