Method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating water culture

Abstract

The invention relates to the technical field of circulating water detection, in particular to a method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating water culture, which comprises the following steps: drawing a standard curve; pretreatment of a water sample: taking a culture water sample, adding a sodium oxalate flocculant, repeatedly and uniformly stirring, standing and then carrying out suction filtration to obtain a filtrate to be detected; and ammonia nitrogen concentration detection. According to the method, a large amount of calcium and magnesium in the circulating aquaculture water are precipitated through the sodium oxalate solution, then a small amount of calcium and magnesium remaining in the aquaculture water are continuously complexed through the potassium sodium tartrate solution, calcium and magnesium ions in the aquaculture water are jointly removed, and the accuracy of ammonia nitrogen concentration detection is guaranteed; in order to avoid precipitation of sodium potassium tartrate due to absorption of carbon dioxide in air, the pH value of the to-be-detected solution is increased by using the sodium hydroxide solution, so that the influence of precipitation of sodium potassium tartrate on the spectroscopic detection result can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of circulating water detection, in particular to a method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating water aquaculture. Background Art

[0002] In recirculating aquaculture, high levels of calcium and magnesium ions are added to enhance the uptake of these elements in the water, particularly for whiteleg shrimp (Penaeus vannamei). Nessler spectrophotometry and salicylic acid spectrophotometry are commonly used to detect trace and semi-trace ammonia nitrogen in water at the milligram per liter level. However, due to the high calcium and magnesium ion content in water, precipitation often occurs with Nessler's and salicylic acid reagents, increasing spectrophotometric errors and even rendering detection impossible. Therefore, we propose a method for detecting ammonia nitrogen in high-calcium and magnesium recirculating aquaculture. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the present invention provides a method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating aquaculture. First, a large amount of calcium and magnesium in the circulating aquaculture water is precipitated with a sodium oxalate solution, and then a small amount of calcium and magnesium remaining in the aquaculture water is further complexed with a potassium sodium tartrate solution to jointly remove calcium and magnesium ions in the aquaculture water, thereby ensuring the accuracy of ammonia nitrogen concentration detection.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for detecting ammonia nitrogen in high calcium and magnesium circulating aquaculture, comprising the following steps: (1) Drawing of the standard curve: Take several colorimetric tubes, add 0.0-0.5 mL of 20 mg / L ammonia nitrogen standard working solution, add sodium oxalate solution filtrate to 5 mL, and the corresponding ammonia nitrogen concentration is 0.0-2.0 mg / L; add 0.10 mL of potassium sodium tartrate solution and shake well, 0.15 mL of sodium hydroxide solution and shake well, and 0.15 mL of Nessler's reagent and shake well to each colorimetric tube in turn; after 15 minutes of color development, use a quartz cuvette to measure the absorbance at a wavelength of 420 nm with ammonia-free water as a reference, and draw a standard curve; (2) Water sample pretreatment: Take the aquaculture water sample, add sodium oxalate flocculant, stir repeatedly, let it stand for 30 minutes, and then filter to obtain the filtrate to be tested; (3) Ammonia nitrogen concentration detection: Take 5.0 mL of the filtrate to be tested and place it in a colorimetric tube. Add 0.10 mL of potassium sodium tartrate solution and shake well, 0.15 mL of sodium hydroxide solution and shake well, and 0.15 mL of Nessler's reagent and shake well. After color development for 30 minutes, use a quartz cuvette to measure the absorbance at a wavelength of 420 nm with ammonia-free water as a reference. The concentration value is obtained according to the standard curve.

[0005] Preferably, in step (1), the amount of 20 mg / L ammonia nitrogen standard solution added to the six colorimetric tubes is 0.0 mL, 0.1 mL, 0.2 mL, 0.3 mL, 0.4 mL, and 0.5 mL, respectively; after the filtrate is extracted with sodium oxalate solution, the corresponding ammonia nitrogen concentrations are 0.0 mg, 0.4 mg, 0.8 mg, 1.2 mg, 1.6 mg, and 2.0 mg / L, respectively.

[0006] Preferably, in step (1), the mass concentration of the filtrate of the sodium oxalate solution is 0.5%, and the preparation method is: take 5.0g of sodium oxalate, shake it with 1000mL of ammonia-free water to dissolve it, let it stand for 30 minutes, and then filter it to obtain it.

[0007] Preferably, in step (1) and step (3), the mass concentration of the potassium sodium tartrate solution is 2%; and the mass concentration of the sodium hydroxide solution is 20%.

[0008] Preferably, in step (2), the solid-liquid ratio of sodium oxalate flocculant to aquaculture water sample is 1:200 g / mL.

[0009] Preferably, in step (2), a water filter membrane with a pore size of 0.45 μm is used in the filtration.

[0010] Preferably, in step (3), after adding sodium hydroxide solution and shaking, if obvious precipitation is found, dilution treatment is performed.

[0011] The present invention provides a method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating aquaculture, which has the following beneficial effects compared with the prior art: The present invention first precipitates a large amount of calcium and magnesium in the circulating aquaculture water by using a sodium oxalate solution, and then continues to complex a small amount of calcium and magnesium remaining in the aquaculture water with a potassium sodium tartrate solution, thereby jointly removing calcium and magnesium ions in the aquaculture water and ensuring the accuracy of ammonia nitrogen concentration detection. In order to prevent the potassium sodium tartrate from precipitating due to absorption of carbon dioxide in the air, etc., the pH of the solution to be detected is increased by using a sodium hydroxide solution, thereby preventing the precipitation of the potassium sodium tartrate from affecting the spectrophotometric detection result. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 This is a flow chart for detecting ammonia nitrogen in aquaculture water according to the present invention; Figure 2 This is the standard curve diagram in Example 1 of the present invention; Figure 3 This is a standard curve diagram in Example 2 of the present invention. DETAILED DESCRIPTION

[0013] The following examples illustrate the implementation methods of the present application in detail, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0014] Example 1 A method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating aquaculture comprises the following steps: S1: Circulating aquaculture water with calcium content of 300 mg / L, magnesium content of 600 mg / L, and ammonia nitrogen of 0.5 mg / L.

[0015] (1) Drawing of standard curve: Take 6 colorimetric tubes, add 0.0mL, 0.1mL, 0.2mL, 0.3mL, 0.4mL, 0.5mL of 20mg / L ammonia nitrogen standard working solution, add 0.5wt% sodium oxalate solution filtrate (preparation method: take 5.0g sodium oxalate, shake and dissolve with 1000mL ammonia-free water, let stand for 30min and then filter) to 5mL, the corresponding ammonia nitrogen concentration is 0.0mg, 0.4mg, 0.8mg, 1.2mg, 1.6mg, 2.0mg / L; add 0.10mL of 2% potassium sodium tartrate solution to each colorimetric tube and shake and mix, 0.15mL 20wt% sodium hydroxide solution and shake well, 0.15mL Nessler's reagent and shake well; after color development for 15 minutes, use a 10mm quartz cuvette to measure the absorbance at a wavelength of 420nm with ammonia-free water as a reference, and draw a standard curve, such as Figure 1 As shown; (2) Water sample pretreatment: Take 200 mL of aquaculture water sample, add 1 g of sodium oxalate flocculant, stir repeatedly, let it stand for 30 minutes, and then filter it using a water filter membrane with a pore size of 0.45 μm to obtain the filtrate to be tested; (3) Pretreatment of spiked water samples: Take 200 mL of aquaculture water sample, 0.2 mL of 500 mg / L ammonia nitrogen standard solution, shake well (the theoretical increase of ammonia nitrogen concentration is 0.5 mg / L), add 1 g of sodium oxalate flocculant, stir repeatedly, let it stand for 30 min, and then filter to obtain the filtrate to be tested; (4) Detection of ammonia nitrogen concentration: Take 5.0 mL of the filtrate to be tested and place it in a 10 mL colorimetric tube. Add 0.10 mL of 2% potassium sodium tartrate solution and shake well, 0.15 mL of 20 wt% sodium hydroxide solution and shake well (if there is obvious precipitation, the water sample to be tested needs to be diluted 5 times before testing), and 0.15 mL of Nessler's reagent and shake well. After color development for 30 minutes, use a 10 mm quartz cuvette to measure the absorbance at a wavelength of 420 nm with ammonia-free water as a reference. The concentration value is obtained according to the standard curve.

[0016] Example 2 A method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating aquaculture comprises the following steps: S2: Circulating aquaculture water with calcium content of 300 mg / L, magnesium content of 600 mg / L, and ammonia nitrogen of 0.5 mg / L.

[0017] (1) Drawing of the standard curve: Take 6 colorimetric tubes, add 0.0mL, 0.1mL, 0.2mL, 0.3mL, 0.4mL, 0.5mL of 20mg / L ammonia nitrogen standard working solution, add ammonia-free water to 5mL, the corresponding ammonia nitrogen concentrations are 0.0mg, 0.4mg, 0.8mg, 1.2mg, 1.6mg, 2.0mg / L; add 0.10mL of 2% potassium sodium tartrate solution and shake well, 0.15mL of 20wt% sodium hydroxide solution and shake well, and 0.15mL of Nessler's reagent and shake well to each colorimetric tube; after color development for 15 minutes, use a 10mm quartz cuvette to measure the absorbance at a wavelength of 420nm with ammonia-free water as a reference, and draw a standard curve, as shown below: Figure 2 As shown; (2) Water sample pretreatment: Take 200 mL of aquaculture water sample, add 1 g of sodium oxalate flocculant, stir repeatedly, let it stand for 30 minutes, and then filter it using a water filter membrane with a pore size of 0.45 μm to obtain the filtrate to be tested; (3) Pretreatment of spiked water samples: Take 200 mL of aquaculture water sample, 0.2 mL of 500 mg / L ammonia nitrogen standard solution, shake well (the theoretical increase of ammonia nitrogen concentration is 0.5 mg / L), add 1 g of sodium oxalate flocculant, stir repeatedly, let it stand for 30 min, and then filter to obtain the filtrate to be tested; (4) Ammonia nitrogen concentration detection: Take 5.0 mL of the filtrate to be tested and place it in a 10 mL colorimetric tube. Add 0.10 mL of 2% potassium sodium tartrate solution and shake well, 0.15 mL of 20 wt% sodium hydroxide solution and shake well (if there is obvious precipitation, the water sample to be tested needs to be diluted 5 times before testing), and 0.15 mL of Nessler's reagent and shake well. After color development for 30 minutes, use a 10 mm quartz cuvette to measure the absorbance at a wavelength of 420 nm with ammonia-free water as a reference. The concentration value is obtained according to the standard curve.

[0018] Example 3 A method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating aquaculture comprises the following steps: S3: Calcium content: 300mg / L, magnesium content: 600mg / L, ammonia nitrogen 0.5mg / L circulating aquaculture water to be tested.

[0019] (1) Drawing of standard curve: Take 6 colorimetric tubes, add 0.0mL, 0.1mL, 0.2mL, 0.3mL, 0.4mL, 0.5mL of 20mg / L ammonia nitrogen standard working solution, add 0.5wt% sodium oxalate solution filtrate (preparation method: take 5.0g sodium oxalate, shake and dissolve with 1000mL ammonia-free water, let stand for 30min and then filter) to 5mL, the corresponding ammonia nitrogen concentration is 0.0mg, 0.4mg, 0.8mg, 1.2mg, 1.6mg, 2.0mg / L; add 0.10mL of 2% potassium sodium tartrate solution to each colorimetric tube and shake and mix, 0.15mL Add 20wt% sodium hydroxide solution and shake well, and 0.15mL Nessler's reagent and shake well; after 15 minutes of color development, use a 10mm quartz cuvette to measure the absorbance at a wavelength of 420nm, using ammonia-free water as a reference, and draw a standard curve; (2) Water sample pretreatment: Take 200 mL of aquaculture water sample, add 1 g of sodium oxalate flocculant, stir repeatedly, let it stand for 30 minutes, and then filter it using a water filter membrane with a pore size of 0.45 μm to obtain the filtrate to be tested; (3) Pretreatment of spiked water samples: Take 200 mL of aquaculture water sample, 0.2 mL of 500 mg / L ammonia nitrogen standard solution, shake well (the theoretical increase of ammonia nitrogen concentration is 0.5 mg / L), add 1 g of sodium oxalate flocculant, stir repeatedly, let it stand for 30 min, and then filter to obtain the filtrate to be tested; (4) Ammonia nitrogen concentration detection: Take 5.0 mL of the filtrate to be tested and place it in a 10 mL colorimetric tube. Add 0.15 mL of Nessler's reagent and shake well. After color development for 30 minutes, use a 10 mm quartz cuvette to measure the absorbance at a wavelength of 420 nm with ammonia-free water as a reference. The concentration value is obtained according to the standard curve.

[0020] Comparative Example 1 A method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating aquaculture comprises the following steps: D1: Circulating aquaculture water with calcium content of 300 mg / L, magnesium content of 600 mg / L, and ammonia nitrogen of 0.5 mg / L.

[0021] (1) Drawing of standard curve: Take 6 colorimetric tubes, add 0.0mL, 0.1mL, 0.2mL, 0.3mL, 0.4mL, 0.5mL of 20mg / L ammonia nitrogen standard working solution, add 0.5wt% sodium oxalate solution filtrate (preparation method: take 5.0g sodium oxalate, shake and dissolve with 1000mL ammonia-free water, let stand for 30min and then filter) to 5mL, the corresponding ammonia nitrogen concentration is 0.0mg, 0.4mg, 0.8mg, 1.2mg, 1.6mg, 2.0mg / L; add 0.10mL of 2% potassium sodium tartrate solution to each colorimetric tube and shake and mix, 0.15mL Add 20wt% sodium hydroxide solution and shake well, and 0.15mL Nessler's reagent and shake well; after 15 minutes of color development, use a 10mm quartz cuvette to measure the absorbance at a wavelength of 420nm, using ammonia-free water as a reference, and draw a standard curve; (2) Water sample pretreatment: Take 200 mL of aquaculture water sample and filter it using a water filter membrane with a pore size of 0.45 μm to obtain the filtrate to be tested; (3) Ammonia nitrogen concentration detection: Take 5.0 mL of the filtrate to be tested and place it in a 10 mL colorimetric tube. Add 0.10 mL of 2% potassium sodium tartrate solution and shake well, 0.15 mL of 20 wt% sodium hydroxide solution and shake well (if there is obvious precipitation, the water sample to be tested needs to be diluted 5 times before testing), and 0.15 mL of Nessler's reagent and shake well. After color development for 30 minutes, use a 10 mm quartz cuvette to measure the absorbance at a wavelength of 420 nm with ammonia-free water as a reference. The concentration value is obtained according to the standard curve.

[0022] Comparative Example 2 A method for detecting ammonia nitrogen in high-calcium and high-magnesium circulating aquaculture comprises the following steps: D2: Circulating aquaculture water with calcium content of 300 mg / L, magnesium content of 600 mg / L, and ammonia nitrogen of 0.5 mg / L.

[0023] (1) Drawing of standard curve: Take 6 colorimetric tubes, add 0.0mL, 0.1mL, 0.2mL, 0.3mL, 0.4mL, 0.5mL of 20mg / L ammonia nitrogen standard working solution, add 0.5wt% sodium oxalate solution filtrate (preparation method: take 5.0g sodium oxalate, shake and dissolve with 1000mL ammonia-free water, let stand for 30min and then filter) to 5mL, the corresponding ammonia nitrogen concentration is 0.0mg, 0.4mg, 0.8mg, 1.2mg, 1.6mg, 2.0mg / L; add 0.10mL of 2% potassium sodium tartrate solution to each colorimetric tube and shake and mix, 0.15mL Add 20wt% sodium hydroxide solution and shake well, and 0.15mL Nessler's reagent and shake well; after 15 minutes of color development, use a 10mm quartz cuvette to measure the absorbance at a wavelength of 420nm, using ammonia-free water as a reference, and draw a standard curve; (2) Water sample pretreatment: Take 200 mL of aquaculture water sample, add 1 g of sodium oxalate flocculant, stir repeatedly, let it stand for 30 minutes, and then filter it using a water filter membrane with a pore size of 0.45 μm to obtain the filtrate to be tested; (3) Pretreatment of spiked water samples: Take 200 mL of aquaculture water sample, 0.2 mL of 500 mg / L ammonia nitrogen standard solution, shake well (the theoretical increase of ammonia nitrogen concentration is 0.5 mg / L), add 1 g of sodium oxalate flocculant, stir repeatedly, let it stand for 30 min, and then filter to obtain the filtrate to be tested; (4) Ammonia nitrogen concentration detection: Take 5.0mL of the filtrate to be tested and place it in a 10mL colorimetric tube. Add 0.10mL of 2% potassium sodium tartrate solution and shake well (if there is obvious precipitation, the water sample to be tested needs to be diluted 5 times before testing), 0.15mL of Nessler's reagent and shake well. After color development for 30 minutes, use a 10mm quartz cuvette to measure the absorbance at a wavelength of 420nm with ammonia-free water as a reference. The concentration value is obtained according to the standard curve.

[0024] Relevant statistics and test data 1. The data of Example 1 (S1), Example 3 (S3), Comparative Example 1 (D1) and Comparative Example 2 (D2) are shown in Table 1. The data of Example 2 (S2) are shown in Table 2.

[0025] Table 1 Data As shown in Table 1: Relative deviation of parallel samples: S1: -0.50%; S3 (the water sample to be tested was not added with 2% potassium sodium tartrate solution and 20wt% sodium hydroxide solution): -0.66%; D1 (the water sample to be tested was not added with sodium oxalate flocculant to remove the influence of calcium and magnesium, and the solution was turbid during spectrometry): 2.14%; D2 (the water sample to be tested was not added with 20wt% sodium hydroxide solution, and the solution was slightly turbid during spectrometry): -2.22%; the more suspended matter in the solution, the greater the difference in the relative deviation of parallel samples will be.

[0026] Spiked recovery rates: S1: 101%; S3: 121%; D1: 57%; D2: 108%. The spiked recovery rate in S1 is closest to 100%, indicating that its detection of ammonia nitrogen concentration is very accurate.

[0027] Table 2 Data As shown in Table 2: When the S2 standard curve was drawn, no 0.5wt% sodium oxalate solution filtrate was added. The recovery rate of water sample S2 using the same method as S1 was 109%, which was 9% higher.

[0028] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for detecting ammonia nitrogen in high calcium and magnesium circulating aquaculture, characterized in that: The following steps are involved: (1) Drawing of the standard curve: Take several colorimetric tubes, add 0.0-0.5 mL of 20 mg / L ammonia nitrogen standard working solution, add sodium oxalate solution filtrate to 5 mL, and the corresponding ammonia nitrogen concentration is 0.0-2.0 mg / L; add 0.10 mL of potassium sodium tartrate solution and shake well, 0.15 mL of sodium hydroxide solution and shake well, and 0.15 mL of Nessler's reagent and shake well to each colorimetric tube in turn; after 15 minutes of color development, use a quartz cuvette to measure the absorbance at a wavelength of 420 nm with ammonia-free water as a reference, and draw a standard curve; (2) Water sample pretreatment: Take the aquaculture water sample, add sodium oxalate flocculant, stir repeatedly, let it stand for 30 minutes, and then filter to obtain the filtrate to be tested; (3) Ammonia nitrogen concentration detection: Take 5.0 mL of the filtrate to be tested and place it in a colorimetric tube. Add 0.10 mL of potassium sodium tartrate solution and shake well, 0.15 mL of sodium hydroxide solution and shake well, and 0.15 mL of Nessler's reagent and shake well. After color development for 30 minutes, use a quartz cuvette to measure the absorbance at a wavelength of 420 nm with ammonia-free water as a reference. The concentration value is obtained according to the standard curve.

2. The method for detecting ammonia nitrogen in high calcium and magnesium circulating aquaculture according to claim 1, characterized in that: In step (1), the amount of 20 mg / L ammonia nitrogen standard solution added to the six colorimetric tubes was 0.0 mL, 0.1 mL, 0.2 mL, 0.3 mL, 0.4 mL, and 0.5 mL, respectively; after the filtrate was extracted with sodium oxalate solution, the corresponding ammonia nitrogen concentrations were 0.0 mg, 0.4 mg, 0.8 mg, 1.2 mg, 1.6 mg, and 2.0 mg / L, respectively.

3. The method for detecting ammonia nitrogen in high calcium and magnesium circulating aquaculture according to claim 1, wherein In step (1), the mass concentration of the filtrate of the sodium oxalate solution is 0.5%, and the preparation method is: take 5.0g of sodium oxalate, shake it with 1000mL of ammonia-free water to dissolve it, let it stand for 30 minutes, and then filter it to obtain it.

4. The method for detecting ammonia nitrogen in high calcium and magnesium circulating aquaculture according to claim 1, wherein In step (1) and step (3), the mass concentration of the potassium sodium tartrate solution is 2%; the mass concentration of the sodium hydroxide solution is 20%.

5. The method for detecting ammonia nitrogen in high calcium and magnesium circulating aquaculture according to claim 1, wherein In step (2), the material-liquid ratio of sodium oxalate flocculant to aquaculture water sample is 1:200 g / mL.

6. The method for detecting ammonia nitrogen in high calcium and magnesium circulating aquaculture according to claim 1, characterized in that: In step (2), a water filter membrane with a pore size of 0.45 μm is used in the filtration.

7. The method for detecting ammonia nitrogen in high calcium and magnesium circulating aquaculture according to claim 1, characterized in that: In step (3), after adding sodium hydroxide solution and shaking, obvious precipitation is found, and dilution treatment is performed.

Images