Abstract
A collaborative study among 18 participating laboratories from five countries was conducted to publish a recommended method for the determination of hydrogen cyanide in mainstream cigarette smoke. Seven cigarette samples (CM9, KR 1R6F, KR 2R5F and four commercial cigarettes) covering a wide range of blends and cigarette design constructions under two smoking regimes (ISO 3308 and ISO 20778) were employed in the study. The improved method involved smoke collection, using a combination of glass fiber filter pad and impinger trap containing dilute sodium hydroxide solution (“pad+impinger”) or using two glass fiber filter pads (one pad treated with an ethanol-water solution of sodium hydroxide plus one blank pad; “pad+pad”). Hydrogen cyanide was determined using a continuous flow analyzer based on the colorimetric detection of the reactants of cyanides with chromogenic reagents such as isonicotinic acid/1,3-dimethyl barbituric acid and pyridine/pyrazolone. Results from smoke collection using the “pad+pad” collection and the “pad+impinger” collection are consistent with each other under both regimes, which suggests each of the two method subtypes can be adopted in the determination of hydrogen cyanide in mainstream cigarette smoke. Statistical analysis was carried out following ISO 5725-2 to generate repeatability (r) and reproducibility (R) data for results from linear and rotary smoking. For reproducibility (R) expressed as a percentage of mean yield across all of the studied products and both smoking regimes, values ranged from 13.6–32.3%. The lowest “tar”-yielding products provided the most variable data. Though the labs were not all using the same smoke collection subtype, the repeatability and reproducibility suggested that the test results were within the range that would likely be deemed acceptable on a long-term basis. Results supporting a robust method for hydrogen cyanide are reported herein and support establishment of a standardized method.