KR101145694B1 - Nitrate concentration measuring method and the measuring kit using thereof - Google Patents

Abstract

The present invention relates to a nitrate nitrogen concentration detection method and detection kit of the water quality measurement method, and more specifically, to a sample containing nitrate nitrogen and a sample obtained by pre-treatment with an oxidizing agent to the sample is a functional coloring reduction powder The present invention relates to a reagent, a detection kit, and a detection method for easily and quickly measuring nitrate nitrogen concentration using an absorbance method or a colorimetric control method.
100 parts by weight of magnesium sulfate anhydrous, 40 to 80 parts by weight of Cadmium powder, 250 to 500 parts by weight of sulfuric acid, 5 to 20 parts by weight of copper (II) sulfate, 100 to 200 parts by weight of 2,5-Dihydroxybenzoic acid, Potassium phosphate monobasic It provides a reducing color functional agent of nitrate nitrogen, characterized in that the composition is 250 to 500 parts by weight to provide a nitrate nitrogen detection kit and detection method.

Description

Nitrogen concentration measurement method and the measuring kit

The present invention relates to a nitrate nitrogen concentration detection method and detection kit of the water quality measurement method, and more specifically, to a sample containing nitrate nitrogen and a sample obtained by pre-treatment with an oxidizing agent to the sample is a functional coloring reduction powder The present invention relates to a reagent, a detection kit, and a detection method for easily and quickly measuring nitrogen nitrate concentration by using absorbance or 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 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.

The prior art is an invention that has an advanced function and effect as compared to the conventional nitrate nitrogen analysis method.

However, the former prior art had a disadvantage in that it is not possible to secure practicality because of the constitutive complexity of the electrochemical biosensor and the inconvenience of management of the carbon electrode to which the nitrate reductase is fixed.

In addition, the latter prior art is a time-consuming and cumbersome process by reducing the process of reducing nitrate nitrogen to nitrite nitrogen and the process of coloring by adding a color aid and a coloring agent, caustic soda, boric acid, oxidizing agent Phosphorous potassium persulfate and the like were similar in function and effect of the conventional oxidizing agent, naphthylethyldiamine chloride and the color supplements sulfanylamide has a disadvantage in that the accuracy is poor in terms of color development.

Therefore, there is a need for a reagent, a detection kit, and a detection method for nitrous nitrogen concentration, which require simple measurement, shorten the time, and require accurate measurement.

In order to solve the above problems,

100 parts by weight of magnesium sulfate anhydrous, 40 to 80 parts by weight of Cadmium powder, 250 to 500 parts by weight of sulfuric acid, 5 to 20 parts by weight of copper (II) sulfate, 100 to 200 parts by weight of 2,5-Dihydroxybenzoic acid, Potassium phosphate monobasic A process for preparing a reducing color functional agent, characterized in that the composition of 250 to 500 parts by weight,

Injecting the reducing coloring functional agent into a sample containing nitrate nitrogen (NO ₃ -N, Nitrate) and reacting to reduce the nitrite nitrogen (NO ₂ -N, Nitrite) and the reduced nitrite nitrogen To react with and cause a change in color,

It provides a method and an analysis kit for measuring the concentration of nitrogen nitrate (NO ₃ -N, Nitrate), including the measurement of the absorbance or colorimetric control method for the changed color.

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.

1 is a calibration line quantifying a standard solution containing nitrate nitrogen using the water quality analysis kit according to the present invention

The present invention, in order to use the absorbance method or colorimetric control method for detecting the concentration of nitrogen nitrate (NO ₃ -N, Nitrate), a substance that functions to reduce the nitrate and color development function (hereinafter, " It is referred to as "reducing color functional agent".

In addition, the present invention provides a nitric acid nitrate concentration detection kit including the reducing coloring functional agent.

In addition, the present invention provides a method for detecting nitrogen nitrate concentration using the reducing coloring functional agent.

Hereinafter, a reduction coloring functional agent, a nitrate nitrogen concentration detection kit, and a method for detecting nitrate nitrogen concentration according to the present invention will be described in detail.

The present invention is to reduce the nitrate nitrogen to nitrite nitrogen, and the functional agent in the form of powder having the function of coloring with the reduced nitrite nitrogen, Magnesium sulfate anhydrous, Cadmium powder, Sulfanilic acid, Copper (II) sulfate, Carboxylic acid , Potassium phosphate monobasic refers to a reducing chromogenic agent (or Cadmium Reduction Powder) formed by mixing.

The reducing color functional agent changes color after a certain time while reducing nitrate nitrogen in a sample taken from river water, river, lake or waste water.

Therefore, it is also a reducing color functional agent which can be used in the sample containing nitrogen nitrate which oxidized the nitrogen component of any of said sample through pretreatment.

Reducing color functional agent of the present invention is prepared by admixing Magnesium sulfate anhydrous, Cadmium powder, Sulfanilic acid, Copper (ll) sulfate, Carboxylic acid, Potassium phosphate monobasic.

The reducing coloring functional agent obtained by mixing the above kinds of materials reduces nitrogen nitrate in a short time and also makes the coloring clear by rapid reaction with the reduced nitrous nitrogen.

In addition, the measurement of the nitrate concentration using a reducing coloring agent according to the present invention, calcium, chlorine, iron ions, nitrite nitrogen (NO ₂ -N, Nitrite), strong oxidation and strong It has a distinct effect of excluding the effect of reducing substances.

Magnesium sulfate anhydrous is anhydrous magnesium sulfate, which is generally used as a hygroscopic agent because of its affinity with water. It is a white crystalline powder of magnesium sulfate. In addition to fillers and mordants of paper, it is used for laxative medicine. There are many hydrous salts besides anhydrous salts. Magnesium sulfate is usually referred to as a seven-hydrate salt, and this is called f-some salt, and the natural ones are particularly called saline salt (瀉 利 鹽). The chemical formula is MgSO ₄ and the anhydrous salt is white crystalline powder, melting point 1185 ° C, specific gravity 2.66. It melts 26.9g at 0 ℃ and 68.3g at 100 ℃ in 100g of water, and slightly soluble in alcohol. The state of the hydrous salt changes depending on the temperature at which the crystals are precipitated from the saturated aqueous solution. Anhydrous salts are produced by the redness of the hydrous salt. The present invention uses anhydrous magnesium sulfate. Anhydrous magnesium sulfate performs the function of reducing nitrogen nitrate and excludes measurement interference materials. In the present invention, the composition of the reducing chromogenic agent acts as a function of excluding interference ions that interfere with the detection of nitric acid. It also acts as a function to make color development accurate and clear when measuring nitrate concentration.

Cadmium powder means cadmium powder. Conventional cadmium powders are used. Preferably, the finer the cadmium powder used in general, the better the reaction surface. The main function of cadmium powder is to reduce nitrate nitrogen. Strong reduction of nitrate nitrogen has the effect of increasing the accuracy of the concentration.

Sulfanilic acid, also called 4-aminobenzene sulfonic acid, forms diazo compounds and is used to make dyes and sulfonamides. In the present invention, it serves as an effect of excluding interference ions, an effect of reducing nitrate nitrogen, and a color developing function.

Copper (II) sulfate is called copper sulfate (CuSO ₄ ) and may be used in any form of copper sulfate depending on the degree of hydration. Copper sulfate is a blue transparent crystal with a specific gravity of 2.286. When placed in dry air, it slowly loses moisture and becomes powder. When heated, it loses 2 molecules of water at 45 ° C, 4 molecules of water at 110 ° C, and all water molecules at 250 ° C, resulting in colorless anhydride. In this invention, it is preferable to use anhydrous copper sulfate. In the present invention, copper sulfate reduces nitrate nitrogen and ionized sulfate has an effect of excluding interference ions that interfere with measurement.

Formic acid, Acetic acid, Chloroacetic acid, Dichloroacetic Acid, Trichloroacetic acid, Trifluoroacetic acid, Oxailc Acid, Benzoic acid can be used. Preferably, the use of Benzoic acid is highly reactive when tested for detection of nitrate nitrogen. More preferably, the use of 2,5-Dihydroxybenzoic acid shows higher reactivity and effect. In the present invention, the carboxylic acid performs a function in which the nitrate nitrogen is combined with the nitrous nitrite nitrogen. In particular, Benzoic acid has a clear and distinct color development effect among carboxylic acids. Among them, 2,5-Dihydroxybenzoic acid has the best color development effect, and also has the effect of excluding the interference of interfering ions.

Potassium phosphate monobasic is water soluble as KH ₂ PO ₄ and is used as a food additive, nutrient or fungicide. However, in the present invention, it serves as an effect of eliminating interference of interfering ions and a function of assisting color development when measuring nitrate nitrogen concentration.

Reducing color functional agent of the present invention is preferably 100 parts by weight of Magnesium sulfate anhydrous, 40 to 80 parts by weight of Cadmium powder, 250 to 500 parts by weight of Sulfanilic acid, 5 to 20 parts by weight of Copper (II) sulfate, Carboxylic acid 100 ~ 200 parts by weight, 250 to 500 parts by weight of Potassium phosphate monobasic is good.

In this case, it was very effective to reduce and develop color. When measuring the nitrate concentration with the water analysis kit using the present invention, the effect of remarkably excluding the interference of the interfering substance (ion material) contained in the sample. have. In particular, when measuring the nitrate nitrogen concentration in the sample by the present invention, as shown in Table 1, the interference limit value of the interference material is very high, there is an effect that can be applied to any sample well. In particular, a sample containing fluorine, which is a strong oxidizing material, has a very effective property in excluding interference of fluorine. In addition, this interference removal effect can be applied very well to samples containing various kinds of cations and anions such as in seawater.

Interference Limits of Interferences Interference Limit value (mg / l) Calcium 100 mg / l Chloride 100 mg / l Ferric ion All levels Nitrite All levels Fluorine ion All levels Strong Oxidation / Reducing Substance All levels

In addition, 5 to 15 parts by weight of fine zinc powder, and 10 to 20 parts by weight of N- (1-naphthyl) ethylenediamine dihydrochloride (NED) based on 100 parts by weight of Magnesium sulfate anhydrous based on the reducing coloring agent of the present invention further reduced A color development agent can also be prepared.

The fine zinc powder functions to increase the ability to reduce nitrate nitrogen in the sample to be measured. The finer the zinc powder is, the smaller the size of the particle size is, and preferably, the size of 10 to 50㎛ is good. The reason why the zinc zinc powder is additionally formed in the reducing coloring agent of the present invention is that the reduction time is shortened.

 The additional miscibility of N- (1-naphthyl) ethylenediamine dihydrochloride (NED) is due to its ability to enhance the ability to develop reduced nitrite nitrogen and to prevent interference with interfering ions.

The above-described reducing color functional agent of the present invention is sufficiently sufficient for reduction, color development, and interference exclusion, but by adding micro zinc powder and N- (1-naphthyl) ethylenediamine dihydrochloride (NED), the concentration of nitrogen nitrate will be very high. It is effective in the case where it is expected and when the interference ion is expected to be excessive.

In addition, the present invention provides a water quality analysis kit comprising the above-described reducing color functional agent.

The water quality analysis kit refers to various types of analytical diagnostic tools for performing water quality analysis. The water quality analysis kit is a device that can diagnose water pollutants by changing the color, color, or color tone by absorbance, colorimetric contrast, etc. Therefore, any kind of water quality analysis kit which analyzes the water quality using the reducing color functional agent of the present invention falls within the protection scope of the present invention.

The present invention also provides a water quality analysis method using the above-described reducing color functional agent. Specifically, it provides a method for detecting the nitrate nitrogen concentration.

Conventional detection method of nitrogen nitrate concentration using the leucine method or ultraviolet absorbance method in the water environmental conservation method, the following is 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, the use of the reducing color functional agent according to the present invention can greatly simplify the preparation, test procedure and method of such a reagent, and shows the same effect as the conventional method in terms of accuracy.

Nitrogen nitrate concentration detection method according to the present invention is as follows.

First, Magnesium sulfate anhydrous, Cadmium powder, Sulfanilic acid, Copper (ll) sulfate, Carboxylic acid, Patassium phosphate monobasic is made of a mixed color reducing functional agent (or Cadmium Reduction Powder) Process, preferably Carboxylic acid is Benzoic acid and more preferably 2,5-Dihydroxybenzoic acid to perform a process for producing a reducing color functional agent.

Specifically, 100 parts by weight of magnesium sulfate anhydrous, 40 to 80 parts by weight of Cadmium powder, 250 to 500 parts by weight of sulfuric acid, 5 to 20 parts by weight of copper (ll) sulfate, 100 to 200 parts by weight of 2,5-Dihydroxybenzoic acid, Potassium phosphate monobasic 250 to 500 parts by weight of the reducing functional agent is prepared.

Reduction chromophoric function of 5 to 15 parts by weight of fine zinc powder and 10 to 20 parts by weight of N- (1-naphthyl) ethylenediamine dihydrochloride (NED) based on 100 parts by weight of Magnesium sulfate anhydrous in the manufacturing process of the reducing chromogenic agent The process of manufacturing an agent can also be performed.

The reduction and coloring process is performed by adding an appropriate amount of the reducing coloring functional agent through the above-described process to the collected sample estimated to include nitrate nitrogen. The proper amount of the reducing coloring agent added to the sample can be sufficiently predicted in consideration of the anticipated contamination of the collected sample and is obvious to those skilled in the art. In this process, all the nitrogen components are oxidized through the pretreatment of the sample to produce nitric nitrate. When all the nitrogen components through the pretreatment are oxidized to nitrate nitrogen, a reducing coloring agent is added to reduce the color of nitrate nitrogen.

The reduced and colored sample is then subjected to a process of measuring the concentration of nitrogen nitrate through absorbance or colorimetric control.

It provides a method for detecting nitric acid nitrate comprising such a process.

Detecting nitrous nitrate by the method for detecting the nitrate nitrogen concentration according to the present invention can not only ensure the accuracy more than the equivalent of the conventional method, but also significantly reduces the measurement time. In addition, it can be measured irrespective of the pH of the measurement sample, there is an effect that can omit the ancillary procedure for adjusting the pH of the measurement sample.

The following is one of the embodiments according to the present invention. However, this embodiment does not reduce the technical spirit and scope of the present invention.

<Examples>

1. Manufacturing method of reducing color functional agent

Reagent 1.

Synonyms : Magnesium sulfate anhydrous ( CAS No .: 7789-88-9)

Reagent 2.

Synonyms : Cadmium powder ( CAS No .: 7440-43-9)

Reagent 3.

Synonyms : Sulfanilic acid ( CAS No .: 121-57-3)

Reagent 4.

Synonyms : Copper (II) sulfate ( CAS No .: 7758-98-7)

Reagent 5

Synonyms : 2,5-Dihydroxybenzoic acid ( CAS No .: 490-79-9)

Reagent 6

Synonyms : Patassium phosphate monobasic ( CAS No .: 7778-77-0)

Combination ratio for each reagent for the production of a reducing color functional agent is as follows.

Combination composition ratio by reagent Reagent # Reagent 1 Reagent 2 Reagent 3 Reagent 4 Reagent 5 Reagent 6 Weight ratio (%) 10 5.5 34.5 One 14 35

When mixed with the weight ratio of the above six reagents is a reducing color functional agent.

And it calculates the concentration of the reduced color-developing function and the appropriate amount of nitrate nitrogen (NO ₃ -N, Nitrate) containing the sample can then react with using the absorption intensity, contrast table colorimetric nitrate nitrogen (NO ₃ -N, Nitrate) .

2. Experimental results

Sample volume: 10ml

사용량 Original Color Function: 70mg

Measurement wavelength: 430 nm

Measuring vessel: 1inch diameter round glass bottle

Response time: 15 minutes

The experimental results are shown in detail in the calibration curve shown in FIG. 1. According to the calibration curve, the test results for the standard solution form an accurate linearity, indicating that the accuracy of the analysis is very high. In addition, as shown in Table 2 below it can be seen that the interference limit of the interference material is also very high.

Interference Limits of Interferences Interference Limit value (mg / l) Calcium 100 mg / l Chloride 100 mg / l Ferric ion All levels Nitrite All levels Fluorine ion All levels Strong Oxidation / Reducing Substance All levels

As described above, when using the water quality analysis kit for measuring the concentration of nitrogen nitrate (NO ₃ -N, Nitrate) according to the present invention, it is possible to exclude the influence of interference by other interference ions contained in the sample. There is a significant effect. In particular, there is a remarkable effect in excluding the interference of fluorine, the biggest interference factor when measuring the nitrate concentration. In addition, it can be measured irrespective of the pH of the sample, there is no need to adjust the pH of the sample.

The nitrate nitrogen detection kit and the detection method according to the present invention can be widely used in water purification and wastewater treatment industry, pollution prevention industry, education business, etc. related to the basic water environment law.

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

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

Claims (5)

In a substance having a reducing and coloring function for detecting nitrate concentration,
Reducing coloring agent composed of Magnesium sulfate anhydrous, Cadmium powder, Sulfanilic acid, Copper (ll) sulfate, Carboxylic acid and Potassium phosphate monobasic.
The method of claim 1,
Carboxylic acid is a reducing coloring agent, characterized in that Benzoic acid or 2,5-Dihydroxybenzoic acid.
The method of claim 2,
100 parts by weight of magnesium sulfate anhydrous, 40 to 80 parts by weight of Cadmium powder, 250 to 500 parts by weight of Sulfanilic acid, 5 to 20 parts by weight of Copper (II) sulfate, 100 to 200 parts by weight of Carboxylic acid, 250 to 500 parts by weight of Potassium phosphate monobasic Reducing color functional agent characterized in that the composition.
The process of reducing the chromic nitrite (NO ₂ -N, Nitrite) by injecting a reducing coloring agent of claim 1 to a sample containing nitrogen nitrate (NO ₃ -N, Nitrate) and reacting React with reduced nitrous nitrogen to cause color change,
Method for measuring the concentration of nitrogen nitrate (NO ₃ -N, Nitrate) including the measurement process by the absorbance or colorimetric control method for the changed color.
A water quality analysis kit comprising the reducing coloring agent of claim 1.

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