Investigating the efficiency of mechanical agitation on the quantification of nicotine in e-cigarettes, using a novel method

Abstract

Electronic cigarettes (ECs) have gained popularity among the general public. ECs have varying nicotine levels from one e-liquid to another. Thus, a standardised method for analysing the nicotine content in e-liquids is needed. Here, a method was developed for quantitative analysis using high-performance liquid chromatography (HPLC) with mechanical agitation (MA). The same elution conditions were applied without mechanical agitation (WMA) to investigate the effect of processing on nicotine separation efficiency. The proposed method resulted in increased linearity in a concentration range of 25–500 ppm. This method also resulted in an increase in the correlation coefficient from 0.2415 to 0.9991, with a limit of detection (LOD) and limit of quantification (LOQ) of 0.09 ppm and 0.29 ppm, respectively, making it more applicable to a wide range of e-liquids in domestic and foreign markets. The analysis of seven e-liquids with concentrations of 0–50 mg/mL revealed that 67% of the samples had a lower nicotine content than that stated on the label. The opposite was true for 33% of samples. No sample matched the nicotine content stated on the label. A sample that was claimed to contain 3 mg/mL actually contained 17 mg/mL. Moreover, a sample labelled as nicotine-free contained 7 mg/mL of nicotine. Another sample was claimed to contain 50 mg/mL, but the measured value was 24 mg/mL. This value exceeds the Saudi Food and Drug Administration (SFDA) standard, which specifies that e-liquids should not contain more than 20 mg/mL of nicotine.