A Combined Colorimetric Determination Method of Total Phosphorus and COD

A chemical oxygen demand and colorimetric determination technology, which is applied in material analysis by observing the influence of chemical indicators, and analysis by chemical reaction of materials. It can solve the problem of high temperature, total phosphorus and COD determination. and other problems, to achieve the effect of being conducive to online monitoring, simple and fast measurement, and easy to popularize and apply.

Inactive Publication Date: 2011-12-21
CHONGQING UNIV
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Problems solved by technology

[0007] In view of this, in order to overcome the shortcomings of the existing total phosphorus and COD determination, such as long time-consuming and high temperature, a combined colorimetric determination method of total phosphorus and chemical oxygen demand is proposed

Method used

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  • A Combined Colorimetric Determination Method of Total Phosphorus and COD
  • A Combined Colorimetric Determination Method of Total Phosphorus and COD
  • A Combined Colorimetric Determination Method of Total Phosphorus and COD

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Embodiment 1

[0034] The present embodiment adopts concentration to be the hydrogen peroxide of 10mM, metal ion adopts the ferrous sulfate that concentration range is 2.5mM, non-reducing acid adopts the sulfuric acid that pH range is 3, malachite green-ammonium molybdate chromogen: ammonium molybdate 2mM, Malachite green 0.2mM, sulfuric acid 0.4M, Triton 0.1% mixed solution, COD chromogenic solution: 100μM malachite green solution.

[0035] The higher the oxidation rate of the digestion method, the more complete the digestion of the water sample, and the closer the measurement result is to the true value. Three phosphorus-containing compounds, adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP), are selected to Evaluate the degradation efficiency of this method. These three compounds are the main products of the metabolism of organisms. They exist in large quantities in cells and are stable in nature. They are often used as standard compounds in the...

Embodiment 2

[0040]In this embodiment, hydrogen peroxide with a concentration of 12 mM is used, ferrous sulfate with a concentration range of 5 mM is used for metal ions, and sulfuric acid with a pH range of 2 is used as a non-reducing acid. Malachite green-ammonium molybdate chromogen: mixed solution of ammonium molybdate 2mM, malachite green 0.2mM, sulfuric acid 0.4M, Triton 0.1%, COD chromogen: 100μM malachite green solution.

[0041] For the determination of total phosphorus, at first, all the switches are in the off state, first turn on the switch 4, enter the water sample, then turn on the switch 2, enter the Fenton reagent, after completing the digestion process, open the switch 3, enter the phosphate chromogenic solution (peacock green-phosphomolybdenum heteropolyacid method), for spectral detection, scanning spectrum see Figure 2A . For the measurement of COD, all the switches are turned off first, turn on switch 4, enter the water sample, turn on switch 1, put malachite green i...

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Abstract

The invention provides an associative colorimetric measuring method for associatively measuring total phosphorus and a chemical oxygen demand (COD), which is characterized by comprising the following steps: based on the associative colorimetric measurement of a Fenton reagent to the total phosphorus and the COD, adopting malachite green-ammonium molybdate as a color-developing agent, forming a colored complex compound through phosphate radicals and the color-developing agent to achieve the measurement of the total phosphorus, adopting a malachite green as the color-developing agent, based on the competition mechanism of the COD and the malachite green, namely, the residual quantity of the malachite green and the COD is in direct proportion in certain time that a system digests, and achieving the measurement of the COD. The key of associative measurement is that: based on the action of the Fenton regent, the total phosphorus and the COD are digested through catalyzing H2O2 (hydrogen peroxide) by a metal ionic catalyst in an acidic medium to generate free hydroxyl radicals (OH-) with strong oxidizability; and by using the associative measurement of the total phosphorus and the COD based on the Fenton reagent, the problems of a conventional measuring method for the total phosphorus and the COD that the reagent types are various, the process is complicated, the time and the energyare consumed, the steps are fussy, a high-temperature concentrated acid is needed, and further, the field quick measurement is not available can be solved.

Description

technical field [0001] The invention relates to the technical field of environmental monitoring, and is a rapid analysis method for joint determination of total phosphorus and chemical oxygen demand. Background technique [0002] Total phosphorus refers to the sum of phosphorus-containing substances that exist in various forms. Chemical oxygen demand (COD) refers to the amount of oxidant consumed by reducing substances in the water body, which is converted into the mass concentration of oxygen, respectively reflecting the richness of the water body. The degree of trophication and the degree of pollution by reducing substances are all indicators that must be measured to evaluate water quality. [0003] The determination of total phosphorus and COD needs to digest the water sample first, and then perform colorimetric determination. The former digests total phosphorus into orthophosphate, and the latter digests reducing substances into carbon dioxide and water. This digestion ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78
Inventor 莫志宏曾一平温志渝黄正勇卢芙蓉
Owner CHONGQING UNIV
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