At the OELCHECK laboratory, a specially adapted investigation method is immediately available with which the proportion of E10 containing ethanol in engine oil can be specified. Since ethanol contains a significant amount of oxygen compared to conventional fuels, the GC method for chromatographic separation of oil and fuel, currently used to determine the petrol and diesel components in engine oil, is not suitable for E10. For the determination of the E10 content in engine oil, the ethanol component is ascertained with a head space gas chromatograph. The glycol content (antifreeze) described in detail in ÖlChecker, Winter 2010, was also measured using the same device and a similar method. With our investigation method specially adapted for the detection of ethanol, the oil sample is heated in a hermetically sealed container, whereby ethanol and petrol evaporate from the oil sample. Only this vapour is injected into the gas chromatograph. After separating all components contained in the vapour by means of a GC column, the ethanol content is indicated as a percentage. The petrol component is still indicated using the conventional GC method contained in the analysis kit 2.