1.1 ,This test method applies to the determination of sulfate sulfur and pyritic sulfur in coal and calculates organic sulfur by difference. This test method is not applicable to coke or other carbonaceous materials. Monosulfides (pyrites and FeS₂ are disulfides) of iron and elements such as cadmium, lead, vanadium, and zinc can be present in coal. In the range of 0 to 100 ppm, these monosulfides do not contribute significantly to the total inorganic sulfide content.