This document specifies a method for the determination of the water soluble chloride, sodium and potassium content in solid biofuels by extraction with water in a closed container and their subsequent quantification by different analytical techniques. The fuel sample is heated with water in a closed container. The concentrations of chloride, sodium and potassium in the obtained water extract are determined by one of the following techniques: - chloride: ion chromatography (IC) or potentiometric titration with silver nitrate; - sodium and potassium: flame emission spectroscopy (FES), flame atomic absorption spectroscopy (FAAS) or inductively coupled plasma optical emission spectroscopy (ICP-OES). This document has been prepared by Technical Committee ISO/TC 238 "Solid biofuels" in collaboration with Technical Committee CEN/TC 335 "Solid biofuels", the secretariat of which is held by SIS (Sweden). This document replaces DIN EN 15105:2011-04. The responsible German committee is Working Committee NA 062-05-82 AA "Biogene Festbrennstoffe" ("Solid biofuels") at the Standards Committee Material Testing (NMP) at DIN.