Method for testing permanganate index though gas phase molecular absorption spectroscopy

A technology of permanganate index and absorption spectroscopy, which is applied in the field of chemical analysis, can solve problems such as large consumption of samples and reagents, manual operation errors, and numerous operation steps, and achieve simplified reagent use requirements, accelerated reaction speed, and easy operation. Effects in simple steps

Inactive Publication Date: 2015-12-30
孙璐
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] (1) It is necessary to use the color change to determine the consumption of reagents and the reaction standard, and the requirements for the clarity of the test water sample are relatively high, and it is difficult to measure samples with high turbidity and color;
[0007] (2) There are many steps such as titration and color difference judgment that require manual operation during the test process, which is easy to introduce manual operation errors and requires high quality of operators;
[0009] (4) The consumption of samples and reagents is large, and the standard method needs to take 100ml of mixed water samples for each test;
[0010] (5) There are many operation steps, the result calculation parameters are many, the calculation is complicated, and it is easy to introduce errors or calculation errors;
[0011] (6) It is difficult to realize high-precision automatic operation, and the number of samples that can be measured every day is small

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] This embodiment is applied to the situation where the chloride ion concentration of the water sample does not exceed 300 mg / L. The standard solution of sodium nitrite was measured by gas phase molecular absorption spectrometer, and the absorbance calibration curve was obtained.

[0033] Separately take 10 mL of mixed water sample (potassium permanganate index of this embodiment is 10 mg / L) in the reaction vessel. Add 0.5mL (1+3) sulfuric acid and mix well. Add 1 mL of 0.0100 mol / L potassium permanganate solution, shake well, and immediately put it in a boiling water bath and heat for 30 minutes (timed from the time when the water bath re-boils). Remove the reaction vessel, add 1 mL of 0.0100 mol / L sodium nitrite standard solution and overdose, shake well. Its chemical reaction equation is: 2KMnO 4 +5NaNO 2 +3H 2 SO 4 →5NaNO 3 +2MnSO 4 +K 2 SO 4 +3H 2 .

[0034] Add 1mL of a mixed solution of 85% hydrochloric acid + 15% ethanol into the reaction vessel contai...

Embodiment 2

[0038]This embodiment is applied to the situation where the chloride ion concentration of the water sample exceeds 300 mg / L. The standard solution of sodium nitrite was measured by gas phase molecular absorption spectrometer, and the absorbance calibration curve was obtained.

[0039] Separately take 10 mL of mixed water sample (the potassium permanganate index of the water sample in this example is 10 mg / L, if the permanganate index is higher than 10 mg / L, take less as appropriate and dilute with water) in the reaction container. Add 0.05mL of 50% sodium hydroxide solution and mix well. Add 1 mL of 0.0100 mol / L potassium permanganate solution, shake well, and immediately put it in a boiling water bath and heat for 30 minutes (timed from the time when the water bath re-boils). Remove the reaction vessel, add a small amount of (1+3) sulfuric acid to make the solution acidic, then add a small amount of 0.0100mol / L sodium nitrite standard solution 1mL and overdose, shake well. ...

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Abstract

The invention discloses a method for testing a permanganate index though gas phase molecular absorption spectroscopy. The method comprises the steps of measuring and picking a defined amount of water to be tested, placing the water into a reaction vessel, adding sulfuric acid so that the mixture can be acidic, or adding sodium hydroxide so that the mixture can be alkaline, then adding a given mass of potassium permanganate solutions, conducting heating reaction for a period of time, so that reducible substances in the mixture are oxidized by potassium permanganate, adding excessive nitrite solutions for conducting reduction on residual potassium permanganate, and then adding hydrochloric acid and ethanol solutions. When ethyl alcohol is added to hydrochloric acid mediums and serves as a catalyst, nitrite can be transformed into NO<2> instantly. Carrier gas is blown into the reaction vessel for loading NO<2> into a gas phase molecular absorption spectrometer, and the watery potassium permanganate content and the watery permanganate index can be obtained through calculation. The method is simple, rapid and convenient in operation step, by using hydrochloric acid and ethyl alcohol as the catalysis solutions, the reaction is greatly accelerated, the testing result is free of tailing peak phenomenon, and errors are minor.

Description

technical field [0001] The invention belongs to the field of chemical analysis, in particular to a gas-phase molecular absorption spectrometry test method for permanganate index. Background technique [0002] The permanganate index is a comprehensive indicator of the pollution degree of surface water bodies by organic pollutants and reducing inorganic pollutants. It refers to the oxygen consumed when treating water samples with permanganate as an oxidant in acidic or alkaline media. Expressed in mg / L of oxygen. Reductive inorganic substances such as nitrite, ferrous salt, sulfide in water and organic substances that can be oxidized under these conditions can consume potassium permanganate. Therefore, the permanganate index is often used as a comprehensive indicator of the pollution degree of surface water bodies by organic pollutants and reducing inorganic substances. [0003] Gas-phase molecular absorption spectroscopy (hereinafter referred to as GPMAS) is based on the pr...

Claims

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Application Information

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IPC IPC(8): G01N21/33
Inventor 孙璐刘丰奎郝俊臧平安王建牛军丁文彬张娟曾祥丽
Owner 孙璐
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