Quantitative ashless filter paper Diameter Ø:150mm X gal is a histochemical substrate 9005 64 5 X gal is a histochemical substrate for β galactosidase which cleaves X Gal to yield an insoluble blue precipitate ROTI®Aqua P C I is the optimal choice for RNA isolation and other procedures where a low phenol pH value is desired 352 and 354 are high purity filter papers suitable for routine quantitative gravimetric techniques and in the preparation of samples for use in the analysis involving instrumental techniques The quantitative grades are manufactured from top quality cotton linters using ultra pure water and further treat with acid to remove any remaining organic and inorganic impurities