Quantitation of Vaporized γ‐Aminobutyric Acid in Cigarette Smoke Extract From e‐Cigarettes by the Combination of HPLC‐Fluorescence Detection and Derivatization With DBD‐F

Abstract

Gamma‐aminobutyric acid (GABA), which has attracted much attention as a bioactive ingredient, is used in functional foods. Recently, electronic cigarette (e‐cigarette) products for inhaling vaporized GABA have become commercially available. In this study, we developed a high‐performance liquid chromatography–fluorescence method for detecting GABA derivatized with 4‐(N,N‐dimethylaminosulfonyl)‐7‐fluoro‐2,1,3‐benzoxadiazole (DBD‐F) in cigarette smoke extract (CSE). The vaporized GABA captured in CSE was derivatized with DBD‐F under moderate conditions (80°C, 30 min). After chromatographic separation, the DBD‐GABA derivative was detected at 437 and 558 nm. The calibration curve of GABA ranging from 10 to 20,000 ng/mL showed good linearity (more than 0.999). The limit of detection at a signal‐to‐noise ratio of 3 was 1.1 ng/mL. The method was applied to the detection of GABA in e‐liquid and CSE for two kinds of e‐cigarette products, and the estimated collection efficiency of GABA was approximately 25%. Furthermore, the detection of minor components, such as glutamine, glutamic acid, and arginine, in the e‐liquid proved that the GABA used in the e‐cigarette was prepared by microbial fermentation.