The formation of three families of oxygenated compounds is studied in the case of isooctane combustion. Stoichiometric, lean and rich conditions are studied at different distances from a flat burner. Nine carbonyl compounds, five alcohols and three organic acids tire found in detectable concentrations in the combustion products. These oxygenated compounds are formed very quickly, their concentrations increase or remain constant for about 2-3 min and then they fall to zero. Generally, in accordance with the results of a spark ignition engine, the oxygenated compounds have a maximum concentration at stoichiometry or under lean conditions. Some combustion products are well correlated, indicating that they are formed in parallel, or one is the precursor of the other. (c) 2005 Elsevier Ltd. All rights reserved.