This European Standard specifies a method based on inductively coupled plasma optical emission spectrometry (ICP OES) for the determination of manganese content from about 0,5 mg/l to about 7,5 mg/l and of iron content from about 1,4 mg/l to about 6,0 mg/l in unleaded petrol containing up to 3,7 % (m/m) oxygen. WARNING - The use of this European Standard may involve hazardous materials, operations and equipment. This European Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this European Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. NOTE 1 Manganese as MMT and iron as ferrocene are added to petrol to increase anti-knock properties. NOTE 2 Solutions of MMT in petrol are unstable when exposed to light. Low and erratic results are expected if petrol samples are exposed to light prior the analysis. Iron and manganese contents higher than 6,0 mg/l and 7,5 mg/l respectively may be measured after preliminary dilution of the sample with a suitable solvent. However, the precision has not been established for such a procedure. Further work regarding automotive ethanol (E85) fuel is on-going in CEN. NOTE 3 For the purposes of this European Standard, the terms "% (m/m)" and "% (V/V)" are used to represent the mass fraction (µ) and the volume fraction () of a material respectively.