Water quality ammonia nitrogen detection reagent and detection method

Abstract

The invention relates to the technical field of water quality monitoring, and discloses a water quality ammonia nitrogen detection reagent which comprises a reagent R1 and a reagent R2, the reagent R1 is prepared from the following raw materials in proportion: 6.40 g of sodium salicylate, 6.40 g of sodium potassium tartrate tetrahydrate, 0.14 g of sodium nitroprusside and 180mL of deionized water; the reagent R2 is prepared from the following raw materials in proportion: 0.3 mL of sodium dichloroisocyanurate, 2.5 g of sodium hydroxide, 3.5 g of sodium silicate nonahydrate and 180mL of deionized water. The detection method of the water quality ammonia nitrogen detection reagent comprises the following steps: S1, pretreating a water sample, removing suspended matters in the water sample, and adjusting the pH value; s2, drawing a standard curve; s3, water sample determination: taking a water sample to be detected, adding an equivalent R1 reagent, uniformly shaking, standing for a period of time, then adding an equivalent R2 reagent into the water sample to be detected, uniformly shaking, and standing until color development is stable; measuring the absorbance of the water sample by using a spectrophotometer; and S4, calculating a result. The detection reagent and the detection method thereof are high in accuracy, simple and convenient to operate, good in stability, environment-friendly, safe and wide in application range.

Description

Technical Field

[0001] The present invention relates to the technical field of water quality monitoring, and in particular to a water quality ammonia nitrogen detection reagent and a detection method. Background Art

[0002] High-concentration ammonia nitrogen wastewater mainly comes from steel manufacturing, feed production, coal coking, chemical refining, oil refining and fertilizer production processes, which are very harmful to the natural environment and the stability of the ecosystem. Ammonia nitrogen is the main aerobic substance in water, which consumes dissolved oxygen in the water, causing the water to become black and smelly, and endangering the living environment of aquatic plants and animals. In addition, ammonia nitrogen in water is converted into nitrite under certain conditions. If it is consumed for a long time, the nitrite in the water will combine with protein to form nitrite nitrogen, which is harmful to human health.

[0003] Spectroscopy achieves rapid, non-destructive detection of pollutants such as ammonia nitrogen by measuring the interaction between matter and electromagnetic radiation. The electrochemical law uses electrodes to react with substances in solution and determines the concentration of ammonia nitrogen by measuring changes in potential or current. Online water quality monitoring instruments are affected by environmental factors (such as temperature, humidity, pressure, etc.) and may drift, affecting the accuracy of monitoring data. Some monitoring instruments may malfunction or degrade in performance during long-term operation, affecting the continuity and stability of monitoring data. The presence of other substances in water may interfere with ammonia nitrogen detection and affect the accuracy of test results. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a water quality ammonia nitrogen detection reagent and a detection method to solve the problems that the existing water quality ammonia nitrogen detection is prone to equipment failure and the equipment is easily affected by the environment.

[0005] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a water quality ammonia nitrogen detection reagent, including R1 reagent and R2 reagent;

[0006] Reagent R1 includes the following raw materials in the following proportions: 6.40 g sodium salicylate, 6.40 g potassium sodium tartrate, 0.14 g sodium nitrosoferricyanide, and 180 mL deionized water;

[0007] The R2 reagent includes raw materials in the following proportions: 0.3 mL of sodium dichloroisocyanurate, 2.5 g of sodium hydroxide, 3.5 g of sodium silicate nonahydrate, and 180 mL of deionized water.

[0008] Furthermore, the preparation method of the above-mentioned water quality ammonia nitrogen detection reagent, R1 reagent is as follows: dissolve 6.40g of sodium salicylate and 6.40g of potassium sodium tartrate in deionized water in sequence, add 0.14g of sodium nitrosoferricyanide to the dissolved solution, and after the sodium nitrosoferricyanide is dissolved, transfer the solution to a volumetric flask with a specification of 200mL, add deionized water to the volumetric flask to the 180mL mark, mix the solution and transfer it to a brown reagent bottle.

[0009] Furthermore, the preparation method of the above-mentioned water quality ammonia nitrogen detection reagent, R2 reagent is as follows: add 2.5g of sodium hydroxide solid to a beaker containing 150mL of deionized water and stir until completely dissolved. After cooling, weigh 0.3mL of sodium dichloroisocyanurate and 3.5g of sodium silicate nonahydrate in turn and add them to the beaker to dissolve. After fully dissolved, transfer to a 200mL volumetric flask, add water to the 180mL mark, and mix well.

[0010] Furthermore, the detection method of the above-mentioned water quality ammonia nitrogen detection reagent comprises the following steps:

[0011] S1, water sample pretreatment, removal of suspended matter and adjustment of pH value;

[0012] S2, standard curve drawing, respectively take different concentrations of ammonia nitrogen standard solutions, add an equal amount of R1 reagent to each, shake well and let it stand for a period of time; then add an equal amount of R2 reagent to each standard solution, shake well again and let it stand until the color is stable; use a spectrophotometer to measure the absorbance of each standard solution, and draw a standard curve with ammonia nitrogen concentration as the horizontal axis and absorbance as the vertical axis;

[0013] S3, water sample determination, take the water sample to be tested, add an equal amount of R1 reagent, shake well and let it stand for a while, then add an equal amount of R2 reagent to the water sample to be tested, shake well and let it stand until the color is stable; use a spectrophotometer to measure the absorbance of the water sample;

[0014] S4, result calculation, according to the measured absorbance of the water sample, find the corresponding ammonia nitrogen concentration on the standard curve.

[0015] The beneficial effects of the present invention are as follows: in the R1 reagent, sodium salicylate is an organic acid salt, which can react with ammonia nitrogen under alkaline conditions to form a colored complex, the color depth of which is proportional to the concentration of ammonia nitrogen, and thus can be used for quantitative detection of ammonia nitrogen. Potassium sodium tartrate is mainly used to mask metal ions in water samples, such as calcium, magnesium, etc. These metal ions can also react with color developers such as sodium salicylate to form colored complexes. By adding potassium sodium tartrate, these interferences can be effectively reduced and the accuracy of detection can be improved. Sodium ferrocyanide is also used to mask metal ions in water samples, especially iron ions.

[0016] In the R2 reagent, sodium dichloroisocyanurate is a strong oxidant that can oxidize ammonia nitrogen to produce nitrogen gas, which helps the color development reaction. Sodium dichloroisocyanurate also has a certain disinfecting effect, which helps to maintain the stability of the reagent and reduce microbial contamination. Sodium hydroxide is used to adjust the pH value of the solution to the alkaline range. Sodium silicate nonahydrate can form a colloid in the solution, which helps to capture and fix the complex generated by the reaction, thereby enhancing the color development effect. DETAILED DESCRIPTION

[0017] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0018] Ammonia nitrogen is one of the important indicators of water pollution. Excessive concentration of ammonia nitrogen will have a serious impact on aquatic ecosystems, including promoting excessive growth of algae, consuming dissolved oxygen in water, affecting water quality, etc. Therefore, accurate and rapid detection of ammonia nitrogen content in water is crucial for environmental protection and water quality management. This embodiment provides a water quality ammonia nitrogen detection reagent and detection method. This water quality ammonia nitrogen detection reagent includes R1 reagent and R2 reagent.

[0019] Preparation of R1 reagent:

[0020] Preparation of raw materials: 6.40 g of sodium salicylate, a white to light yellow crystalline powder with good solubility, used to react with ammonia nitrogen under alkaline conditions to form a colored complex; 6.40 g of potassium sodium tartrate, a white crystalline powder; 0.14 g of sodium ferrocyanide, a light yellow crystal; 180 mL of deionized water, used to dissolve the above substances to ensure the purity of the reagents.

[0021] First, add about 90 mL of deionized water to a clean beaker, heat it to a slight boil using a magnetic stirrer, slowly add 6.40 g of sodium salicylate, and continue stirring until it is completely dissolved and the solution is clear and transparent. Then, add 6.40 g of potassium sodium tartrate in batches while stirring continuously to ensure that no solid particles remain and the solution remains uniform.

[0022] After the above solution has cooled to room temperature, weigh 0.14 g of sodium ferrocyanide and add it to the beaker, avoiding direct contact with solid particles and splashing. Continue stirring until the sodium ferrocyanide is completely dissolved and the solution changes color slightly, but should remain transparent.

[0023] Transfer the prepared solution to a clean and dry 200mL volumetric flask, rinse the inner wall of the beaker with deionized water several times to ensure that there is no residue. Then continue to add deionized water to the volumetric flask until the liquid level is close to the scale line, and use a dropper to add dropwise until the concave liquid surface of the solution is just tangent to the scale line. Cover the bottle cap and gently shake the volumetric flask to mix the solution evenly.

[0024] Transfer the prepared R1 reagent to a brown reagent bottle and store it away from light to prevent decomposition of photosensitive components.

[0025] Preparation of R2 reagent:

[0026] Preparation of raw materials: 0.3 mL of sodium dichloroisocyanurate; 2.5 g of sodium hydroxide, which is a white solid and a strong base, used to adjust the pH value of the reaction system; 3.5 g of sodium silicate nonahydrate, which is a white to light yellow crystal, used as a stabilizer and complexing agent; 180 mL of deionized water, used to dissolve the above substances.

[0027] In another clean beaker, add about 150 mL of deionized water and slowly add 2.5 g of solid sodium hydroxide, stirring while adding until it is completely dissolved and the solution releases heat and becomes slightly hot.

[0028] After the sodium hydroxide solution is cooled to room temperature, 0.3 mL of sodium dichloroisocyanurate solution and 3.5 g of sodium silicate nonahydrate are added in sequence, and stirring is continued until they are completely dissolved and the solution becomes transparent without precipitation or suspended matter.

[0029] Transfer the above solution to a 200 mL volumetric flask, rinse the inner wall of the beaker with deionized water several times, then add deionized water to the volumetric flask to the scale line, and shake gently to mix the solution evenly.

[0030] R2 reagent does not need to be stored away from light, but should be stored in a sealed container to prevent moisture absorption or contamination.

[0031] Water quality ammonia nitrogen detection:

[0032] To draw the standard curve, take different concentrations of ammonia nitrogen standard solutions, such as 0 mg / L, 1 mg / L, 2 mg / L, 3 mg / L and 4 mg / L. Add an equal amount of R1 reagent to each, shake well and let it stand for a while; then add an equal amount of R2 reagent to each standard solution, shake well again and let it stand until the color is stable; use a spectrophotometer to measure the absorbance of each standard solution, and draw a standard curve with ammonia nitrogen concentration as the horizontal axis and absorbance as the vertical axis.

[0033] For water sample determination, take a certain amount of the water sample to be tested, add an equal amount of R1 reagent, shake well and let it stand for a while, then add an equal amount of R2 reagent to the water sample to be tested, shake well and let it stand until the color is stable; use a spectrophotometer to determine the absorbance of the water sample.

[0034] Calculate the results and find the corresponding ammonia nitrogen concentration on the standard curve based on the measured absorbance of the water sample.

[0035] The ammonia nitrogen influent and ammonia nitrogen effluent of the sewage treatment system were tested for ammonia nitrogen concentration using ammonia nitrogen testing instruments and testing reagents, and the data in Table 1 were obtained:

[0036]

[0037] As can be seen from the table, there are certain differences between the results of instrument testing and laboratory testing. The concentration of ammonia nitrogen influent detected by the instrument is generally lower than the result of laboratory testing. This difference is expressed as a negative percentage, such as "-5.28%" means that the instrument detection value is 5.28% lower than the laboratory detection value.

[0038] There are also differences between instrument detection and laboratory detection of ammonia nitrogen effluent concentration, but the direction and magnitude of the differences vary. In some cases, the instrument detection value is higher than the laboratory value (such as +3.93% and +23.23%), and in some cases it is lower than the laboratory value (such as -13.33% and -23.46%). This inconsistency shows that the detection of effluent ammonia nitrogen concentration is more easily affected by multiple factors such as detection conditions and sample processing.

[0039] The water quality testing site is equipped with online instruments, and the laboratory test data is compared with the online instruments. The online instruments are not accurate in the water inlet data, and the instrument maintenance cycle is long. Laboratory testing can provide more accurate and reliable water quality parameters and help determine the calibration and maintenance needs of online instruments.

[0040] Laboratory testing can be used as a supplement to on-site online instruments, especially during online instrument failure or maintenance. Through regular laboratory testing, the continuity and stability of water quality monitoring can be ensured, and potential water quality problems can be discovered and resolved in a timely manner.

Claims

1. A water quality ammonia nitrogen detection reagent, characterized in that, Including R1 reagent and R2 reagent; The R1 reagent includes the following raw materials in the following proportions: 6.40 g sodium salicylate, 6.40 g potassium sodium tartrate, 0.14 g sodium nitrosoferricyanide and 180 mL deionized water; The R2 reagent includes raw materials in the following proportions: 0.3 mL of sodium dichloroisocyanurate, 2.5 g of sodium hydroxide, 3.5 g of sodium silicate nonahydrate, and 180 mL of deionized water.

2. The water quality ammonia nitrogen detection reagent according to claim 1, characterized in that: The preparation method of the R1 reagent is as follows: 6.40g of sodium salicylate and 6.40g of sodium potassium tartrate are dissolved in deionized water in sequence, 0.14g of sodium nitrosoferrocyanide is added to the dissolved solution, and after the sodium nitrosoferrocyanide is dissolved, the solution is transferred to a 200mL volumetric flask, deionized water is added to the volumetric flask to the 180mL mark, and the solution is mixed and transferred to a brown reagent bottle.

3. The water quality ammonia nitrogen detection reagent according to claim 1, characterized in that: The preparation method of the R2 reagent is as follows: add 2.5g of sodium hydroxide solid to a beaker containing 150mL of deionized water and stir until completely dissolved; after cooling, weigh 0.3mL of sodium dichloroisocyanurate and 3.5g of sodium silicate nonahydrate in turn and add them to the beaker to dissolve; after fully dissolving, transfer to a 200mL volumetric flask, add water to the 180mL mark, and mix well.

4. The method for detecting ammonia nitrogen in water according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, water sample pretreatment, removal of suspended matter and adjustment of pH value; S2, standard curve drawing, respectively take different concentrations of ammonia nitrogen standard solutions, add an equal amount of R1 reagent to each, shake well and let it stand for a period of time; then add an equal amount of R2 reagent to each standard solution, shake well again and let it stand until the color is stable; use a spectrophotometer to measure the absorbance of each standard solution, and draw a standard curve with ammonia nitrogen concentration as the horizontal axis and absorbance as the vertical axis; S3, water sample determination, take the water sample to be tested, add an equal amount of R1 reagent, shake well and let it stand for a while, then add an equal amount of R2 reagent to the water sample to be tested, shake well and let it stand until the color is stable; use a spectrophotometer to measure the absorbance of the water sample; S4, result calculation, according to the measured absorbance of the water sample, find the corresponding ammonia nitrogen concentration on the standard curve.

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