The HI93754C COD kit contains 25 ready-to-use vials containing pre-measured reagents. These high quality reagents follow follow an adaptation of the dichromate method for COD determination. In this method, a heated digestion is required to oxidize organic matter in the sample. During the digestion, hexavalent chromium in the reagent is reduced to trivalent chromium. The amount of reduced chromium is then measured colorimetrically. The intensity of color is determined by a compatible photometer and the COD concentration is displayed in mg/L (ppm) O2. These reagents are designed to be used with samples that have an expected range of 0 to 15000 mg/L (ppm) O2.
Hanna vials contain approximately 3 mL of pre-dosed reagent so the user simply needs to add a small quantity of the sample. With pre-dosed vials, test preparation time is dramatically reduced and there is no time-consuming reagent preparation procedure or glassware cleaning. The vials and caps of the COD reagents have been designed to avoid accidental reagent spills. Due to the pre-dosed reagents, the amount of chemicals and handling time is also minimized.