1.1 This part of ISO 6528 specifies a method for the determination, by combustion in a furnace, of the total sulfur content of raw rubbers, unvulcanized compounded rubbers and vulcanizates, including sulfur present as barium sulfate, calcium sulfate and lithopone. 1.2 It is applicable to chlorinated rubbers, nitrile rubbers and hydrocarbon rubbers (including natural rubber). The determination is not affected by the presence of metal salts which form insoluble sulfates.