The method given is applicable to copper, lead and zinc sulfide concentrates free from volatile organic flotation reagents, e.g. kerosene, and with hygroscopic moisture contents between 0,05 % (m/m) and 2 % (m/m). It is used to correct the analysis results from the equilibrated moisture level to the dry basis. This method is not applicable to sulfide concentrates which are susceptible to oxidation. Annex A sets out a modified procedure which can be used in this case.