KR101204561B1 - Nitrate concentration measuring method - Google Patents

Abstract

PURPOSE: A nitrate nitrogen concentration detection method is provided to shorten times needed for detection of nitrate nitrogen concentration and to implement the detection without the influence of other ions contained in a specimen. CONSTITUTION: A nitrate nitrogen concentration detection method includes the following steps: a phosphoric acid solution and a dimethyl phenol solution are added into a specimen containing nitrate nitrogen to be detected; the color change of the specimen is induced; and the induced color change of the specimen is compared with a color chart to detect the concentration of the nitrate nitrogen. In the process of the color change induction, the nitrate nitrogen in the specimen is reacted with the phosphoric acid solution and the dimethyl phenol solution to generate 4-nitro-2,6-dimethylphenol.

Description

Nitrate concentration measuring method

The present invention relates to a nitrate nitrogen concentration detection method of the water quality measurement method, and more specifically, to the sample containing the nitrate nitrogen and the sample collected by adding a nitrate nitrogen detection reagent to the reaction and the color of the absorbance method or The present invention relates to a detection method for simple and rapid measurement of nitric acid concentration using colorimetric control.

Recently, as environmental regulations on pollutants such as nitrogen and phosphorus contained in river water, lakes and waste water are gradually strengthened, various types of water quality measurements have been made on discharge water or river water. In addition to the basic requirements to ensure precision and reproducibility, the characteristics required for water quality measurement should be fast, convenient, environmentally friendly and economical.

In particular, nitrate (NO ^3- ) is one of the well-known water pollutants. Extensive contamination with nitrate ions poses a serious threat to the environment and human health. Therefore, the analysis of nitrate ions is very important. Ingestion of high levels of nitrate for a long time is very likely to cause cancer of the digestive system. In addition, exposure to high concentrations of nitric acid is a cause of blue baby (Blue Baby).

In many countries, the maximum concentration of nitrates in drinking water is between 400 and 800 μM, and the US Environmental Protection Agency (EPA) specifies up to 700 μM. There are three main methods of chemical measurement of nitrate ions. In direct measurement, there are colorimetry, ion-selective electrode, ion chromatography, and indirect measurement. (polarization), and the method of reducing nitrate with nitrite, ammonia, or nitrogen oxide and then measuring it (Sah, RN Commun. Soil Sci. plant Anal. 1994, 25, 2841).

Korea's water pollution process test method uses the leucine method and ultraviolet absorbance method as the representative absorbance method.

However, these methods are less specific, causing many ions to interfere. Therefore, it is inconvenient and time-consuming because it requires a pretreatment process before measurement.

For this reason, patent application 10-2005-0043195 relates to a biosensor for detecting nitrate ions and a measuring method using the same. More specifically, the patent application 10-2005-0043195 has a working electrode having a nitrate reductase (NaR), a reference electrode, and a counter electrode. Biosensors and methods for measuring the nitrate concentration in a sample using the same or a nitrate ionization reactor for converting nitrogen compounds other than nitrates into nitrates can be measured.

In addition, the patent 10-2005-0111069 is characterized in that the analysis of nitrate nitrogen consists of a powder reagent reducing agent, a liquid reagent coloring aid, a liquid reagent coloring agent, a mixture of caustic soda and boric acid as an oxidizing aid to the sample. , By adding potassium persulfate as an oxidizing agent and thermally reacting to convert organic nitrogen and ammonia nitrogen to nitrate nitrogen, and adding a reducing agent to convert nitrate nitrogen to nitrite nitrogen, which is sad again as a color aid Nylamide and ethylenediamine chloride were added as a coloring agent, followed by color spectrophotometry to measure the absorbance, and quantitative determination of total nitrogen. 0.002 to 0.0012 soda, 0.009 to 0.006 boric acid, 0.009 to 0.006 potassium persulfate as an oxidizing agent, and 0.0001 to 0.0001 to sulfanylamide as a color aid 0.0005, and a service 0.0000198 chloride ethylenediamine as developers to analysis reagents, characterized in that added at the rate of 0.000025 compositions and assay method using the same bar.

In the conventional absorbance method, there are disadvantages in that many ions interfere with the use of the leucine method and the ultraviolet absorbance method due to the lack of specificity.

In addition, there is a disadvantage in that the pretreatment process is required before measuring the sample for the above reason, which is inconvenient and time-consuming.

In addition, the present invention has been time-consuming and cumbersome by separately treating the process of reducing the nitrate nitrogen to nitrite nitrogen and the process of coloring by the addition of a color aid and a colorant to attempt to solve this problem remarkably.

In addition, the conventional method for measuring nitrate nitrogen has a disadvantage in that the color development agent naphthylethyldiamine and the color aid adjunct sulfanylamide is less effective in terms of color development, and the accuracy is lowered.

In order to solve the above problems,

A process of inducing color change by adding a predetermined amount of a phosphoric acid solution and a dimethylphenol solution to a sample containing nitrate nitrogen to be measured, and comparing the induced color change with a colorimetric table for a standard solution. A method of detecting nitrogen concentration is provided.

In addition, a process of inducing color change by adding a predetermined amount of a phosphoric acid solution and a dimethylphenol solution to a sample containing nitrogen nitrate to be measured, and determining the degree of color change by using an absorbance method. It provides a method for detecting.

In addition, the phosphoric acid solution is prepared by mixing distilled water, Phosphoric Acid, Sulfuric Acid, and the dimethylphenol solution is provided by detecting distilled water, dimethylphenol, Isopropanol composition provides a method for detecting the nitrate nitrogen concentration.

In addition, the color change induction process is characterized in that the nitrate nitrogen, characterized in that the process of producing a colored 4-nitro-2,6-dimethylphenol by the interaction between the phosphate acid solution and the dimethyl phenol solution and the nitrate nitrogen Provided are methods for detecting concentrations.

The nitric acid nitrate concentration detection kit and the detection method of the present invention have an effect that the measurement time can be significantly shortened as compared with the conventional nitrogen nitrate concentration detection method.

In addition, the present invention has a very simple measurement procedure compared to the conventional nitrogen nitrate concentration detection method has the effect of reducing a lot of effort.

In addition, the present invention has a remarkable effect of eliminating the influence of interference by other kinds of ions contained in the sample appearing in the method for measuring the nitrate nitrogen concentration. In particular, it has a remarkable effect in excluding the interference of fluorine, which is the biggest interference factor when measuring nitrate nitrogen.

In addition, it can be measured irrespective of the pH of the measurement sample, there is no need to adjust the pH of the measurement sample.

In addition, the reducing color functional agent, which is a reagent material of the nitrate nitrogen concentration detection kit and the detection method of the present invention, is easy to manufacture and inexpensive.

In addition, the conventional method for detecting the concentration of nitrogen nitrate requires a complicated procedure such as evaporating and drying the sample, adding sulfuric acid, and adding sodium hydroxide while heating again, but the method for detecting the concentration of nitrate according to the present invention solves this inconvenience. It works.

1 is a calibration curve for the standard solution.

Hereinafter, the present invention will be described in detail.

The present invention provides a detection method which remarkably improves the measurement method using the absorbance method or colorimetric control method, which is a method for detecting the concentration of nitrate nitrogen.

The present invention provides a method for detecting nitrate nitrogen concentration by using the degree of color development by reacting the nitrate nitrogen detection reagent to the sample containing the nitrate nitrogen to be measured.

The present invention has special technical features in the above nitrate detection reagent.

Nitrogen nitrate concentration detection reagent of the present invention comprises a phosphonic acid solution (Phosphoric Acid Solution) and dimethylphenol solution (dimethylphenol Solution).

The phosphoric acid solution is prepared by mixing distilled water, Phosphoric Acid, Sulfuric Acid.

Preferably, 100 parts by weight of distilled water may be mixed with 200 to 400 parts by weight of Phosphoric Acid and 400 to 800 parts by weight of sulfuric acid. In the case of such a composition, the effect of increasing the color reaction by reacting with the sample is obtained.

Phosphoric Acid means phosphoric acid, and the chemical formula is also called H3PO4, orthophosphoric acid, and regular phosphoric acid. Colorless, transparent syrupy, odorless liquid, easy to absorb moisture in the air and colored when in contact with organic matter. Anhydrides are columnar crystals. Usually phosphoric acid has about 22% water. In the present invention, it is preferable to use phosphoric acid as CAS No .: 7664-38-2.

In the present invention, consistently describing Cas No. and characterizing the compound should be interpreted as meaning a compound having the same or similar properties and physicochemical properties as the Cas No. compound.

Sulfuric acid refers to sulfuric acid and is a colorless nonvolatile liquid having the chemical formula H2SO4. It is industrially produced using platinum or vanadium pentoxide catalyst. Except for water, it is the most strongly produced acidic compound.

Sulfuric acid in the present invention is Preference is given to using CAS No .: 7664-93-9.

The dimethylphenol solution is prepared by mixing distilled water, dimethylphenol, Isopropanol.

Preferably dimethylphenol solution (dimethylphenol Solution) is characterized in that the composition was prepared by mixing 100 parts by weight of Demineralized Water, 0.5 to 4 parts by weight of dimethylphenol, 15 to 35 parts by weight of Isopropanol.

The dimethylphenol of the present invention may use a conventional dimethylphenol, more preferably using 2,6-dimethylphenol has the effect of increasing the color sensitivity. More preferably, CAS No .: 576-26-1 is preferably used.

Isopropanol of the present invention is CH3CH (OH) CH3, molecular weight 60.10, boiling point 82.5 ℃. It is a flammable liquid that mixes well with water, alcohol, ether and chloroform. However, it does not dissolve in salt solution and is used for extracting antifreeze, various solvents, alkaloids or cosmetics as well as medicaments such as preservatives and fungicides.

Isopropanol of the present invention has a property of being well mixed with water, thereby inducing a reaction with the nitrate nitrogen of the sample through interaction with the dimethylphenol.

The present invention provides a method for detecting nitrate nitrogen concentration in a sample by using a nitrate nitrogen detection reagent composed of the above-mentioned Phosphoric Acid Solution and dimethylphenol Solution.

Conventional nitrogen nitrate concentration detection method using the leucine method or ultraviolet absorption spectroscopy method in the water conservation method, the following describes one of the detection method of nitrogen nitrate concentration by the conventional absorbance method.

<Existing method>

end. Reagent preparation

(1) Sodium salicylate solution

Dissolve 1 g of sodium salicylate in sodium hydroxide solution (0.01 N) to make 100 ml.

(2) sodium chloride solution

0.2 g of sodium chloride is dissolved in water to make 100 ml.

(3) Ammonium sulfamate solution

0.1 g of ammonium sulfamate is dissolved in water to make 100 ml.

(4) Sodium hydroxide solution (2 → 5)

Dissolve 40 g of sodium hydroxide in water to make 100 ml.

(5) Nitric acid standard stock solution

After drying for 4 hours at 105 ~ 110 ℃, 0.722g of potassium nitrate cooled in desiccator is dissolved in water to make 1L, and 2 drops of chloroform are added and stored in a brown bottle (1ml of this solution is 0.1mg of nitrogen nitrate). Containing).

(6) Nitric Nitrate Standard Solution

Dilute the nitric acid standard stock solution 100 times with water, make it for use (1 ml of this solution contains 0.001 mg of nitric acid).

I. Examination process

(1) analysis

(A) Add a suitable amount of inspection (containing 0.001 to 0.2 mg of nitrate nitrogen) to a 100 ml beaker, add 1 ml of sodium salicylate solution, 1 ml of sodium chloride solution, and 1 ml of ammonium sulfamate solution, and evaporate to dryness in a water bath. .

(B) Cool it, add 2 ml of sulfuric acid, stir it occasionally, leave for 10 minutes (if there is a large amount of evaporation residue, heat it for 10 minutes in a water bath and cool it), and add 10 ml of water to a Nessler tube.

(C) Cool it again, add 10 ml of sodium hydroxide solution (2 → 5) slowly, and add water to make 25 ml.

(D) A portion of this solution was placed in an absorption cell (10 mm), and the absorbance was measured at a wavelength of about 410 nm using a blank test solution which was tested by a method such as inspection using a photospectrometer or photophotometer as a control solution. From the calibration curve prepared in accordance with (2), determine the amount of Nitrate in the test solution and measure the concentration of Nitrate in the test.

(2) Preparation of calibration curve

0-20 mL of nitrate nitrogen standard solution is added to the beaker in a stepwise manner, and tested as described in (1) above to determine the relationship between the amount of nitrate and the absorbance to determine the concentration of nitrate.

The conventional methods described above have the disadvantage that the preparation and test procedures of the measurement reagents are not only complicated, but also require a lot of skill in the measurement methods.

However, if the detection method using the nitrate nitrogen detection reagent according to the present invention is carried out, the preparation, test procedure, and method of such a reagent can be significantly simplified, and the same effect as the conventional method is obtained in terms of accuracy.

The present invention has a constant reaction time after adding a certain amount of phosphonic acid solution and dimethylphenol solution simultaneously or sequentially to a certain amount of solution containing nitrogen nitrate (NO3-N, Nitrate).

The detection reagents may be added at the same time, but preferably, the dimethylphenol solution is added sequentially after the phosphoric acid solution is added.

The reaction time may be determined by the estimated concentration of nitrate nitrogen contained in the sample, and the present invention is preferably about 1 to 10 minutes and about 3 minutes is sufficient.

In addition, the amount of the phosphoric acid solution and the dimethylphenol solution added to the sample may be determined by the nitrate nitrogen concentration as mentioned above, and in the present invention, it is preferable to use 0.5 to 2 ml based on the sample amount of 2 ml.

Phosphoric acid solution and dimethyl nitrate (NO3-N, Nitrate) met with the reaction time during the reaction time to form a colored 4-nitro-2,6-dimethylphenol through the interaction. A method for detecting nitrate nitrogen concentration is provided by comparing or comparing the degree of color change with the color developed by mixing the nitrate nitrogen detection reagent with respect to the standard solution for each nitrate nitrogen concentration.

Various methods of contrasting or comparing the color development of the sample and the standard solution may be employed. Preferably, the concentration of nitrogen nitrate (NO3-N, Nitrate) may be calculated by using absorbance or colorimetric comparison. Can be.

Therefore, the present invention can calculate the concentration of nitrate nitrogen contained in the sample by using the absorbance method or the colorimetric control method by mixing the above-described nitrate nitrogen detection reagent with the sample.

Absorption spectroscopy used in the present invention means a conventional method of obtaining the concentration of the target component by measuring the degree of light absorption at a specific wavelength by changing the target component in the sample solution into a light absorbing material with a suitable reagent, as mentioned above. .

The absorbance method of the present invention obtains the concentration of a target component by applying Lambert Beer's law. A typical absorbance analyzer includes a light source unit, a wavelength selection unit, a sample unit, and a photometric unit.

As a method of measuring the concentration in the absorbance method, there is a colorimetric method using the degree of color development, and a turbidity method using the degree of suspension of the sample solution. Absorption spectroscopy makes a control solution corresponding to the sample liquid to measure the absorbance, and accordingly prepares a calibration curve and then measures the absorbance of the sample liquid and compares the concentration with the calibration curve.

In the present invention, both the colorimetric method and the colorimetric method can be used, and preferably, the colorimetric method has high accuracy.

In addition, the colorimetric contrast method is as follows.

As described above, a standard solution is prepared according to various concentrations of a desired component, and the standard colorimetric table is set by adding the nitrate nitrogen detection reagent of the present invention to the standard solution.

And it means a method of measuring the concentration of the sample solution by comparing the color development degree of the mixed color reaction obtained by mixing the above-mentioned nitrate nitrogen detection reagent to the sample with the standard colorimetric table.

Therefore, the present invention will include any method of measuring the concentration using the degree of miscibility of the nitrate nitrogen detection reagent of the present invention to the sample and the color development will be included in the technical content of the present invention.

An embodiment according to the present invention will be described. Embodiment of the present invention is not intended to limit the technical content of the present invention and should not be construed to reduce the scope of rights.

<Examples>

1. Prepare the nitrate nitrogen detection reagent of the present invention.

(1) Preparation of Phosphoric Acid Solution

Reagent 1 Synonyms : Demineralized Water, CAS No .: 7732-18-5, 10g

<Reagent 2> Synonyms : Phosphoric Acid, CAS No .: 7664-38-2, 30g

<Reagent 3> Synonyms : Sulfuric Acid, CAS No .: 7664-93-9, 60g

To prepare a phosphoric acid solution.

2. Preparation of Dimethylphenol Solution

Reagent 1 Synonyms : Demineralized Water, CAS No .: 7732-18-5, 80g

<Reagent 2> Synonyms : 2,6-dimethylphenol, CAS No .: 576-26-1, 1g

Reagent 3 Synonyms : Isopropanol, CAS No .: 67-63-0, 19g

The above reagents were mixed to form a dimethylphenol solution.

2. Nitrate Nitrogen Detection Process

(1) absorbance spectroscopy

1) 1 ml of the prepared phosphoric acid solution and 1 ml of dimethylphenol solution are sequentially mixed with 2 ml of the sample containing nitrate nitrogen to induce color development.

The reaction time was about 3 minutes.

The sample is measured using the absorbance method.

Measuring wavelength: 370nm, Measuring vessel: 5 Inch round glass bottle with diameter.

2) Prepare calibration curve for standard solution.

The control calibration curve for the standard solution is shown in FIG. 1.

By comparing the control curve and the absorbance of the sample, the accurate nitrate nitrogen concentration is measured.

(2) colorimetric contrast method

As described above, a colorimetric table for the standard solution is prepared to compare the color development of the color-induced sample to calculate the nitrate nitrogen concentration.

As shown in Table 1 below, the present invention exhibits a high limit that can exclude the effects of ion interference.

Therefore, when using the nitrate nitrogen detection method according to the invention it can be seen that the effect of significantly reducing the effect of interference by other kinds of ions contained in the sample.

Interference Limit value (mg / l) K +, Na +, Cl- 500 mg / l COD 200 mg / l Ag + 100 mg / l Cr6 + 5mg / l Ferric ion 10 mg / l Nitrite 10 mg / l Pb2 +, Zn2 +, Hg2 +, Cd2 +, Sn2 + 50 mg / l NH3 + 100 mg / l

As described above, the present invention provides a method for detecting nitrate nitrogen concentration using the nitrate nitrogen detection reagent which is a feature of the present invention.

The present invention can be widely used in water purification and sewage water treatment business, pollution prevention business, education business, etc. related to the Framework Act on Water Environment.

In addition, the present invention can be widely used for pollution prevention monitoring industry, environmental policy related business of national and local government.

In addition, it is a very useful invention for water quality analysis chemicals business, water quality analysis chemical manufacturing industry, environmental supervision business, environmental modeling business, environmental impact assessment business and educational data providing business.

Claims (4)

A process of inducing color change by adding a predetermined amount of a phosphoric acid solution and a dimethylphenol solution to a sample containing nitrogen nitrate to be measured,
And detecting the nitrate nitrogen concentration by comparing the induced color change with the colorimetric table for the standard solution.
A process of inducing color change by adding a predetermined amount of a phosphoric acid solution and a dimethylphenol solution to a sample containing nitrate nitrogen to be measured,
Detecting the nitrate concentration using the absorbance method.
The method according to claim 1 or 2,
The color change induction process is characterized in that the nitrate nitrogen concentration characterized in that a process of producing a colored 4-nitro-2,6-dimethylphenol through the interaction of the phosphate acid solution and the dimethyl nitrate solution with the dimethylphenol solution How to detect.
The method according to claim 1 or 2,
Phosphoric acid solution is prepared by mixing distilled water, Phosphoric Acid, Sulfuric Acid,
Dimethyl phenol solution is a distilled water, dimethylphenol, isopropanol composition for detecting the nitrate nitrogen concentration, characterized in that the composition.

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