This International Standard describes a method for the determination of platinum in platinum jewellery alloys, preferably within the range of fineness specified in ISO 9202, by means of inductively coupled plasma optical emission spectrometry (ICP-OES).This method applies to platinum jewellery alloys that might contain silver, indium, iridium, gallium, copper, cobalt, nickel, tin, and ruthenium. However, this list is not exhaustive and care is always to be taken to investigate potential interference effects.This method is intended to be used as the recommended method for the determination of fineness in alloys covered by ISO 9202 up to 990 ‰.