This document specifies an inductively coupled plasma optical emission spectrometry (ICP-OES) method for the determination of sodium, potassium, calcium, phosphorus, copper and zinc concentrations of diesel fuels, including those containing up to 30 % (V/V) fatty acid methyl ester (FAME), in the range detailed in Table 1. These six elements are considered as the most essential ash forming elements. The number of six was chosen in order to limit the complexity of the test and to be able to determine a decent method precision. The six elements were specified by the vehicle manufacturers. The test provides additional information to the more common ash concentration determination methods which do aim towards filter problems. Metals have more impact on the durability of modern DPF exhaust gas after-treatment systems in diesel vehicles than ash in general. A weighed amount of diesel fuel sample is diluted with an organic solvent. The solution is then introduced directly into an ICP OES spectrometer. Sodium, potassium, calcium, phosphorous, copper and zinc concentrations are determined by comparison with calibration solutions. An Internal Standard is employed to correct viscosity effects. This document has been prepared by Technical Committee CEN/TC 19 "Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin", the secretariat of which is held by NEN (Netherlands). The responsible German committee is Working Committee NA 062-06-11 AA "Atomspektrometrie" ("Atomic spectrometry") of the Petroleum, Fuels, Lubricants and Related Products Standardization Committee (FAM) at the Materials Testing Standards Committee (NMP).