Other Trapping Products,Bird Feeders,Box Traps,Animal Snares Hebei Liebang Metal Products Co.,Ltd , https://www.lbtraps.comThe mixture of water sample, potassium dichromate, silver sulfate solution (catalyst makes the oxidation of linear aromatic compounds more fully) and concentrated sulfuric acid is heated to 175 ℃ in the digestion tank, during which chromium ions are used as oxidants from the VI value The color is changed by reducing to III valence. The degree of color change corresponds to the content of organic compounds in the sample. The instrument directly displays the COD of the sample through colorimetric conversion