Most commonly used for grade for coarser precipitates such as lead- iron- and silver sulphide, alkali carbonates, lead chromate, arsenic, antimony, cadmium and food stuffs. Our ashless quantitative filter papers are made with 100% cotton linters. As quantitative analysis requires a high purity paper these are washed out with acid and finally cleaned with demineralised water. The ash content is 0.007%