Determination of Carbonyl Compounds Generated from the Electronic Cigarette Using Coupled Silica Cartridges Impregnated with Hydroquinone and 2,4-Dinitrophenylhydrazine

• Published in: Bunseki kagaku Vol. 60; no. 10; pp. 791 - 797
• Main Authors: OHTA, Kazushi, UCHIYAMA, Shigehisa, INABA, Yohei, NAKAGOME, Hideki, KUNUGITA, Naoki
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Science and Technology Agency 2011
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.60.791

The electronic cigarette, introduced recently to the marketplace, is a battery-powered device that provides tobacco-like smoke by heating a chemical solution into a vapor. There is, however, little information available regarding the safety of the electronic cigarette, because analysis of the smoke produced is very difficult due to the nature of the chemical components, e.g. acrolein and other carbonyls. Recently, an effective method for the determination of acrolein and other carbonyls using a dual-cartridge system has been developed. Each cartridge consists of reagent-impregnated silica particles ; the first contains hydroquinone (HQ) for the inhibition of acrolein polymerization, while the second contains 2,4-dinitrophenylhydrazine (DNPH) for the derivatization of carbonyls. Samples were drawn through the cartridge, first through the HQ-impregnated silica and then the DNPH-impregnated silica. During extraction, excess DNPH was washed into the HQ bed, where it reacted with acrolein and other trapped carbonyls to form the corresponding hydrazone derivatives. All of the hydrazones derived from airborne carbonyls were completely separated and measured using HPLC. In this study, we analyzed carbonyl compounds generated by the electronic cigarette using the HQ-DNPH technique. Results showed that formaldehyde, acetaldehyde, acrolein, glyoxal and methyl glyoxal were contained in the electronic cigarette smoke. The maximum concentration of formaldehyde was 260 mg/m3. Depending on the brand, cartridges usually contain humectants to produce the vapor (e.g. ethylene glycol, propylene glycol or glycerol) and flavors (e.g. tobacco, mint, fruit and chocolate). Therefore, a simple electronic cigarette was made, comprising a coiled Nichrom wire and glycols ; a voltage of 1.5∼7.5 V was applied to the Nichrom wire. It was found that when the voltage exceeded 3 V, a mist containing carbonyl compounds was generated. From the results, it was elucidated that ethylene glycol was oxidized to formaldehyde and glyoxal ; propylene glycol was oxidized to formaldehyde, acetaldehyde and methylglyoxal ; and glycerol was oxidized to formaldehyde, acrolein, glyoxal and methylglyoxal.