Characterization of Nicotine Salts in 23 Electronic Cigarette Refill Liquids.
Level 5 - mechanism / opinion, no new human data
Bench/laboratory chemical analysis without human participants (Oxford CEBM Level 5).
PubMed 31821492 · doi:10.1093/ntr/ntz232
What was done
Twenty-three commercially available electronic cigarette refill liquids advertised as containing nicotine salts were purchased and analyzed for the presence of 11 potential organic acids. Samples were tested using liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) methods and compared against authentic reference standards.
What was found
Six of the 11 candidate acids were detected across the samples: lactic, benzoic, levulinic, salicylic, malic, and tartaric acid (from most to least common). Most liquids contained one acid type, three liquids contained multiple acids, and in one liquid no target acid was identified. Specific acid concentrations and numerical distributions were not reported in the abstract.
Why it matters
Nicotine salt formulations use organic acids to neutralize free-base nicotine, which may reduce airway irritation and facilitate nicotine uptake. Identifying the actual acids present in commercial products provides an empirical baseline for evaluating their pharmacological and toxicological profiles.
Limits
The sample was limited to 23 commercial products and screened for only 11 pre-selected acids. The study evaluated chemical composition only, without reporting quantitative concentrations, liquid pH values, or direct human sensory or pharmacological outcomes.
Cited by
- supports E-cigarette manufacturers alter the pH of nicotine solutions to reduce throat irritation and bypass the respiratory tract's natural aversion reflex.