The invention discloses a method for measuring dissolved
oxygen in
aquaculture tail water by a spectrophotometric method based on an
iodine-
ascorbic acid-
potassium dichromate
system, and belongs to the technical field of
water quality detection. The method comprises the following steps: sequentially adding a
manganese sulfate solution and an alkaline
potassium iodide solution into a to-be-detected culture
tail water sample, sealing a container, fully reacting, and standing after the reaction is finished to completely precipitate Mn2O3; adding a
citric acid solution, sealing, reacting, completely dissolving the precipitate and releasing the
iodine elementary substance, adding water and an
ascorbic acid-
potassium dichromate mixed color developing agent into the solution after the reaction is finished, fixing the volume, sealing, uniformly mixing, and carrying out a color developing reaction in a dark place; a blank sample is used for reference, the culture
tail water subjected to color development is placed in a
sample pool of a spectrophotometer, the spectrophotometric value of the sample is measured at the
wavelength of 360 nm, and the dissolved
oxygen concentration is calculated according to a standard curvilinear equation. The method provided by the invention reduces the
detection limit of the traditional spectrophotometric method, and has the advantages of high sensitivity, strong anti-interference capability, high speed and rapidness in operation, wide application range, greenness and
environmental protection.