Measurement method for permanganate index and application

Abstract

The invention discloses a measurement method for a permanganate index. The method comprises the following steps: (1) adding a to-be-measured water sample into a colorimetric tube provided with a plug, adding (1+10) sulfuric acid for acidification, adding a potassium permanganate solution, and shaking uniformly; (2) digesting the water sample in the step (1) under a certain condition and quickly cooling to a room temperature; (3) adding an excessive ammonium ferrous sulfate solution into a digestion solution in the step (2), and shaking uniformly; (4) adding a proper amount of a sulfosalicylic acid aqueous solution into a reaction solution in the step (3) for producing a color development reaction; (5) performing absorbance testing on the water sample in the step (4) by taking de-ionized water as a reference at the wavelength of 510 nm, and calculating the permanganate index of the water sample by a formula IMn=-8.5*(A-A0), wherein in the formula, IMn is the permanganate index of the water sample, A is the absorbance of the water sample, and A0 is the absorbance of a blank solution. The measurement method is quick and accurate in detection, suitable for batch measurement and simple to operate, and can be widely applied to laboratory detection and outdoor emergency detection.

Description

technical field [0001] The present invention relates to a detection method of water quality, in particular to a principle of using sulfosalicylic acid and ferric iron to react under acidic conditions to produce a purple complex, and to measure the permanganate index of water by colorimetry In addition, the present invention also relates to the application of the determination method in water quality detection. Background technique [0002] The permanganate index refers to the amount of oxidant consumed to oxidize reducing substances in the water body with potassium permanganate as the oxidant under certain conditions, expressed in mg / l of oxygen (O2, mg / l). Permanganate index, as a comprehensive indicator for judging water body pollution by organic matter and reducing inorganic matter, is suitable for detecting the pollution degree of surface water, ground water, drinking water, etc. At present, the determination of permanganate index mostly uses sodium oxalate as a reducin...

AI Technical Summary

Problems solved by technology

However, due to the high sensitivity of the display substance generated in this method, it needs to be diluted before measuring the absorbance, so the operation process is relatively cumbersome, and the method needs to introduce the metering method of sodium nitrite, and the amount of sodium nitrite is taken The error will directly cause the measurement error of the permanganate index

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