Labelling Accuracy in Low Nicotine e-cigarette Liquids from a Sampling of US Manufacturers

<p> <strong> Objectives </strong> : To assess labelling accuracy for low nicotine concentration e&hyphen;cigarette liquids.</p><p> <strong> Methods </strong> : Nicotine concentration in twelve e&hyphen;liquids, available in 3 and 6 mg/ml strengths, was assayed (5 replicates each) using liquid chromatography&ndash;tandem mass spectrometry.</p><p> <strong> Key findings </strong> : Average nominal concentrations of nicotine were lower than reported in 23/24 products tested, with 2/12 products labelled 3 mg/ml, and 3/12 of the 6 mg/ml products showing statistically significant differences from controls.</p><p> <strong> Conclusions </strong> : Despite the emergence of a global regulatory environment for e&hyphen;cigarettes, inaccuracies still exist in nicotine concentration labelling, which may affect user habits and reliability of products used in smoking cessation.</p>