Exhalation of hydrocarbons by animals

Experimenters with animals have adopted two practical approaches. The alkanes are excreted in small concentrations (nanomoles/litre of expired air) and it is usual to concentrate the gases before analysis by trapping the alkanes by concentration of a large volume of gas by condensation on cold precolumns. In a typical experiment the head 

Lawrence and Cohen (1984) found that ethane was not well absorbed by alumina. They described a method for concentrating ethane, ethylene and longer chain hydrocarbons contained in up to 50 ml of air. They used a closed system in which the air, exhaled by mice allowed to breathe hydrocarbon scrubbed air was filtered through sulphuric acid and potassium hydroxide to trap ammonia and carb-ondioxide, and condensed on a cold finger immersed in solid CO2/ 

Methods utilizing isolated, perfused whole organs and cells or cell organelles 

Muller and Sies (1984) constructed a simple apparatus consisting of a glass manifold through which alkane-free air passed into a glass flask filled with water and then into a 20 or 60 ml gas-tight Erlenmeyer flask with side arm (Fig. 5.15). 

Cells and cell-organelles were incubated at 37°C in the Erlenmeyer flask, and 8 ml aliquots withdrawn from the gas-phase at intervals using Hamilton gas-tight syringes. Aliquots were then injected into the sampling loop of a gas-chromatograph. 

---