Introduction: We evaluate the accuracy of nicotine concentration labeling on electronic cigarette refill products.
Methods: The nicotine concentration of 71 electronic cigarette refill fluid products and 1 related do-it-yourself (DIY) product was quantified using high-performance liquid chromatography. Quantified data were compared to manufacturers labeled concentrations.
Duplicate refill fluid products purchased at different times were evaluated by visual comparison of fluid coloration and quantified nicotine concentration.
Results: Thirty-five of the 54 nicotine-containing fluids had quantified nicotine concentrations that deviated by more than・}10% from the manufacturer labels with 46 of 50 being in excess of labeled values. Refill fluids labeled as 0 nicotine had no detectable nicotine. Of the 5 products that were unlabeled for nicotine concentration, 3 contained no detectable nicotine, whereas the remaining 2 contained nicotine in excess of 100 mg/ml and may have been intended for DIY use. Sixteen of the 18 duplicate bottles of refill fluid varied greatly in their nicotine concentrations. One of the 5 companies showed significant improvement in labeling accuracy in the most recently purchased products. Of the 23 total duplicate pairs, 15 of 23 varied in coloration from their mates.
Conclusions: Nicotine concentration labeling on electronic cigarette refill products was often inaccurate but showed improvement recently in products from 1 company. To ensure the safety of refill fluids and DIY products, it is necessary to establish quality control guidelines for the manufacturing and labeling and to monitor products longitudinally.