Labelling accuracy in low nicotine e-cigarette liquids from a sampling of US manufacturers

OBJECTIVES: To assess labelling accuracy for low nicotine concentration e-cigarette liquids. METHODS: Nicotine concentration in twelve e-liquids, available in 3 and 6 mg/ml strengths, was assayed (5 replicates each) using liquid chromatography-tandem mass spectrometry. KEY FINDINGS: 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. CONCLUSIONS: Despite the emergence of a global regulatory environment for e-cigarettes, inaccuracies still exist in nicotine concentration labelling, which may affect user habits and reliability of products used in smoking cessation.