Uptake of 19 hydrocarbon vapors inhaled by F344 rats

The comparative rates of uptake of 19 hydrocarbon vapors by rats were determined by a dual-column gas chromatograph method. The hydrocarbons ranged in volatility from propylene (BP -47.7 degrees C) to 1,2,4-trimethylbenzene (BP 169 degrees C). Representative compounds from the chemical classes of alkenes, alkynes, straight-chain and branched alkanes, alicyclics, and aromatics were examined. Trends observed included: (1) highly volatile hydrocarbons were less well-absorbed than less volatile hydrocarbons; (2) unsaturated compounds were better absorbed than saturated ones; and (3) branched hydrocarbons were less well-absorbed than unbranched ones. The data indicate that uptake rates among inhaled hydrocarbon vapors may be predicted from the molecular structures and physical properties of the hydrocarbons.