Method for detecting content of ammonia nitrogen in alkaline vanadium-containing solution

Abstract

The invention provides a method for detecting the content of ammonia nitrogen in an alkaline vanadium-containing solution. The method comprises the steps that (1) the vanadium-containing solution is pretreated, colorless vanadium-containing solution treatment liquid is obtained, the pH value of the vanadium-containing solution is adjusted to be 8-9, and heating treatment is conducted under the condition of 40-65 DEG C; (2) filtering the vanadium-containing solution treatment solution to obtain a purified solution, and selectively diluting in combination with the concentration of the purified solution to obtain a diluted solution; (3) uniformly mixing the solution obtained in the step (2) with non-ammonia water, a sodium potassium tartrate solution, a sodium hydroxide solution and a Nessler reagent, and measuring the absorbance of the mixed solution at the wavelength of 420nm by taking the non-ammonia water as a reference reagent; and calculating the ammonia nitrogen content in the vanadium-containing solution by combining a standard curve based on the absorbance value. According to the method provided by the invention, rapid and accurate analysis of the ammonia nitrogen content in the vanadium-containing solution can be realized through Nessler reagent colorimetry.

Description

Technical Field

[0001] The invention relates to the technical field of analysis and detection, and in particular to a method for detecting the ammonia nitrogen content in an alkaline vanadium-containing solution. Background Art

[0002] With the development of the energy storage industry, vanadium batteries play an increasingly important role in the energy storage industry. The main raw material of vanadium batteries is high-purity V 2 O 5 The preparation technology is generally to use crude V 2 O 5 The finished product of ammonium polyvanadate (or ammonium metavanadate) is dissolved in alkali and then impurities are removed to obtain a pure vanadium-rich solution, which is then subjected to ammonium salt precipitation and calcined to obtain high-purity V 2 O 5 During the dissolution of ammonium polyvanadate (or ammonium metavanadate), NH 4 + It will have a great impact on the subsequent impurity removal. At the same time, in the process of using ammonium salt precipitation method, NH 4 + Most of it is transferred to the vanadium precipitation wastewater and generates a large amount of production wastewater, the ammonia nitrogen concentration of which can reach more than 3000 mg / L.

[0003] Conventional ammonium ion detection methods can use distillation or ion chromatography. Ion chromatography will affect the determination of trace ammonium ions due to the high vanadium ion concentration in the vanadium-containing solution and the different valence states of vanadium ions in the solution. The distillation method can eliminate the influence of vanadium ion concentration and color on ammonia nitrogen content, but the operation is more complicated and consumes more electricity.

[0004] The analysis and detection of ammonia nitrogen content in vanadium-containing solutions still needs further improvement. Summary of the invention

[0005] In order to solve the above technical problems, the present invention has developed an analytical method suitable for determining the ammonia nitrogen content in a vanadium-containing solution by Nessler's reagent method, so as to realize accurate and efficient analysis of the ammonia nitrogen content in the vanadium-containing solution. The present invention provides a method for detecting the ammonia nitrogen content in a vanadium-containing solution, which is suitable for detecting the ammonia nitrogen content in a vanadium-containing solution under alkaline conditions. The method provided by the present invention utilizes the colorless property of vanadium (V) in an alkaline solution, and can directly detect the ammonia nitrogen content without removing the vanadium in the vanadium-containing solution, and realizes rapid and accurate analysis of the ammonia nitrogen content in the vanadium-containing solution by Nessler's reagent colorimetry.

[0006] Specifically, the present invention provides the following technical solutions:

[0007] In a first aspect of the present invention, a method for detecting the ammonia nitrogen content in a vanadium-containing solution is provided, comprising:

[0008] (1) pre-treating the vanadium-containing solution to obtain a colorless vanadium-containing solution treatment solution, wherein the pre-treatment comprises adjusting the pH value of the vanadium-containing solution to 8 to 9 and heating the solution at 40 to 65 degrees Celsius;

[0009] (2) filtering the vanadium-containing solution treatment liquid to obtain a purified liquid, and selectively diluting the purified liquid according to its concentration to obtain a diluted liquid;

[0010] (3) uniformly mixing the solution obtained in step (2) with ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent, using ammonia-free water as a reference reagent, and measuring the absorbance of the solution at a wavelength of 420 nm;

[0011] Based on the absorbance value, the ammonia nitrogen content in the vanadium-containing solution to be tested is calculated in combination with a standard curve;

[0012] The standard curve is obtained by uniformly mixing ammonia nitrogen standard solution, ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent, placing the mixture in a fixed state, using ammonia-free water as a reference reagent, and measuring the absorbance at a wavelength of 420 nm.

[0013] The method provided by the present invention utilizes the colorless property of vanadium (V) in alkaline solution, adjusts the pH of the vanadium-containing solution to 8-9, the solution is colorless, and then the absorbance of the solution is determined by Nessler colorimetry, thereby realizing the direct detection of ammonia nitrogen content without removing vanadium from the vanadium-containing solution. The method provided by the present invention converts the colored vanadium-containing solution into colorless by adjusting the pH and heating at elevated temperature, and then realizes the rapid and accurate analysis of the ammonia nitrogen content in the vanadium-containing solution by Nessler's reagent colorimetry.

[0014] According to an embodiment of the present invention, the above method for detecting the ammonia nitrogen content in the vanadium-containing solution may further include the following technical features:

[0015] According to an embodiment of the present invention, the heating treatment time in step (1) does not exceed 20 minutes.

[0016] According to an embodiment of the present invention, the filtration treatment in step (2) is performed using a 0.22 micron filter membrane.

[0017] According to an embodiment of the present invention, the ammonia nitrogen standard solution is prepared by dissolving ammonium chloride dried to a constant weight in pure water and then continuously diluting the solution. The mass volume ratio of the ammonium chloride to the pure water is 0.382 g:100 ml.

[0018] According to an embodiment of the present invention, the concentration of the sodium hydroxide solution is 200-400 g / L, and the concentration of the potassium sodium tartrate solution is 400-600 g / L.

[0019] According to an embodiment of the present invention, the standard curve is prepared by the following method:

[0020] Take a series of different volumes of ammonia nitrogen standard solution in a 100ml volumetric flask, add ammonia-free water to about 75ml, continue to add 2ml potassium sodium tartrate solution, 3ml sodium hydroxide solution and 2ml Nessler's reagent and dilute to the scale with ammonia-free water, shake well. After leaving it for 10 minutes, measure the absorbance at a wavelength of 420nm with ammonia-free water as a reference to obtain a standard curve.

[0021] According to an embodiment of the present invention, the ammonia nitrogen standard solution is prepared by dissolving 0.382 g of ammonium chloride dried to constant weight in 100 ml of pure water and then diluting it 100 times. The volumes of the ammonia nitrogen standard solution are 1 ml, 5 ml, 10 ml, 15 ml, and 20 ml, respectively.

[0022] According to an embodiment of the present invention, the concentration of the sodium hydroxide solution is 320 g / L, and the concentration of the potassium sodium tartrate solution is 500 g / L.

[0023] According to an embodiment of the present invention, the concentration range of the standard curve is 0.1-2 mg / L.

[0024] In a second aspect of the present invention, a method for detecting the ammonia nitrogen content in a vanadium-containing solution is provided, comprising:

[0025] (1) pre-treating the vanadium-containing solution to obtain a colorless vanadium-containing solution treatment solution, wherein the pre-treatment comprises adjusting the pH value of the vanadium-containing solution to 8 to 9 and heating the solution at 40 to 65 degrees Celsius for no more than 20 minutes;

[0026] (2) filtering the vanadium-containing solution treatment liquid to obtain a purified liquid;

[0027] (3) diluting the purified liquid to obtain a diluted liquid;

[0028] (4) mixing the diluent, ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent uniformly, using ammonia-free water as a reference reagent, and measuring the absorbance of the solution at a wavelength of 420 nm;

[0029] Based on the absorbance value, the ammonia nitrogen content in the vanadium-containing solution to be tested is calculated in combination with a standard curve;

[0030] The standard curve is obtained by mixing ammonia nitrogen standard solution and ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent, placing them in a state, using ammonia-free water as a reference reagent, and measuring the absorbance at a wavelength of 420 nm. The concentration of the standard curve is 0.1-2 mg / L.

[0031] The concentration of the sodium hydroxide solution is 320 g / L, and the concentration of the potassium sodium tartrate solution is 500 g / L.

[0032] The method for detecting the ammonia nitrogen content in a vanadium-containing solution provided by the present invention has at least the following beneficial effects:

[0033] (1) The method provided by the present invention has a wider detection range. The method provided by the present invention can achieve a wider detection range by diluting the vanadium-containing solution.

[0034] (2) The method provided by the present invention is safe and convenient. The method provided by the present invention is simple and convenient, involving basic operations such as weighing, heating, dilution, and absorbance measurement. These operations are simple to operate, non-hazardous, easy to operate, and easy to master.

[0035] (3) The method provided by the present invention has accurate results. The present invention uses Nessler's reagent to develop color and then uses a spectrophotometer to measure the absorbance, which is not only fast but also accurate and reliable.

[0036] (4) The method provided by the present invention is fast and efficient. Once the standard curve is drawn, it is only necessary to dilute and inject the sample to be tested, and a single sample can be completed within 10 minutes.

[0037] (5) The method provided by the present invention can save reagents. The samples prepared by the present invention can be directly detected without adjusting the pH, and only a small amount of reagents are needed for subsequent masking and color development. Compared with the distillation method, which uses a large amount of high-concentration alkali solution to neutralize concentrated sulfuric acid, the cost is relatively high; the method provided by the present invention is very low in cost. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below. The embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0039] The present invention provides a method for detecting the ammonia nitrogen content in a vanadium-containing solution, comprising:

[0040] (1) Perform appropriate pretreatment according to the state of the vanadium-containing solution to be tested to obtain a colorless vanadium-containing solution treatment solution.

[0041] The pretreatment of the vanadium-containing solution is to adjust the pH to 8-9, take a sample and place it in a 10 ml centrifuge tube and heat it at 40-65° C. to make it fade. According to a specific embodiment, the heating time should be controlled within 20 minutes (according to a preferred embodiment, the heating time is 5-10 minutes at 40-65 degrees Celsius). Too long a heating time will lead to inaccurate test results.

[0042] By adjusting the pH value, vanadium (V) will become pentavalent in alkaline solution, and the solution will appear colorless, resulting in a colorless vanadium-containing solution treatment liquid; during the research process, it was found that if the pH value is not well controlled, ammonia is easy to volatilize, thus affecting the accuracy of the test results, so it is necessary to adjust the pH value of the vanadium-containing solution to 8-9 through pretreatment. During the experiment, it is necessary to ensure that a colorless vanadium-containing solution treatment liquid is obtained. Heating treatment can effectively ensure that a colorless vanadium-containing solution treatment liquid is obtained. The heating temperature cannot be too high or too low. If it is too low, a colorless vanadium-containing solution treatment liquid cannot be obtained, and there may be a faint color in the liquid, which affects the subsequent determination of the absorbance value, thereby affecting the accuracy; if it is too high, ammonia is easy to volatilize, thereby affecting the accuracy of the test results.

[0043] (2) filtering the vanadium-containing solution treatment liquid to obtain a purified liquid;

[0044] The filtration process can be performed using a 0.22 micron filter membrane, for example, a 0.22 micron PES filter head.

[0045] (3) diluting the purified liquid to obtain a diluted liquid;

[0046] For example, the purification solution can be diluted with distilled water to make NH 4+ The concentration is within the detection range, and a dilution is obtained;

[0047] (4) The diluent is mixed evenly with ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent, and the ammonia-free water is used as a reference reagent to measure the absorbance of the solution at a wavelength of 420 nm; based on the absorbance value, the ammonia nitrogen content in the vanadium-containing solution is calculated in combination with a standard curve.

[0048] The vanadium-containing solutions mentioned include but are not limited to homemade vanadium-containing solutions, or any other vanadium-containing solutions to be tested. These solutions can be in liquid form themselves, or can be prepared from solid form into liquid form, including but not limited to ammonium metavanadate, ammonium polyvanadate, ammonium vanadate, ammonium sulfate, vanadyl sulfate, etc.

[0049] According to a specific implementation method, a proper amount of diluent can be taken into a 100 mL volumetric flask with a pipette, and ammonia-free water can be added to 75 ml, 2 ml of potassium sodium tartrate solution can be added, 3 ml of sodium hydroxide solution can be added, and 2 ml of Nessler's reagent can be added, and the ammonia-free water can be diluted to the scale, and the solution can be shaken well. After standing for 10 minutes, the absorbance can be measured at a wavelength of 420 nm, with ammonia-free water as a reference.

[0050] The standard curve can be drawn according to the following method:

[0051] Take a series of different volumes of ammonia nitrogen standard working solution in a 100ml volumetric flask, add ammonia-free water to about 75ml, continue to add 2ml potassium sodium tartrate solution, 3ml sodium hydroxide solution and 2ml Nessler's reagent and dilute to the scale with ammonia-free water, and shake well. After standing for 10 minutes, measure the absorbance at a wavelength of 420nm with water as a reference to obtain a standard curve. The ammonia nitrogen standard working solution used is prepared by dissolving 0.382g of ammonium chloride dried to constant weight in 100ml pure water and then diluting it 100 times;

[0052] The series of ammonia nitrogen standard working solutions with different volumes are 1 ml, 5 ml, 10 ml, 15 ml and 20 ml respectively.

[0053] The sodium hydroxide solution used is 320 g / L, the potassium sodium tartrate solution is 500 g / L, and the Nessler's reagent mentioned can be prepared by yourself or purchased. The Nessler's reagent used in the examples was purchased from Hunan Huihong Reagent Co., Ltd.

[0054] The concentration range of the standard curve used is 0.1 to 2 mg / L. When measuring the absorbance value, a 2 cm cuvette can be used.

[0055] The technical scheme of the present invention is described below by specific examples. It should be noted that these examples are only used to facilitate the understanding of those skilled in the art and should not be regarded as limiting the scope of protection of the present invention. The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents, materials, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0056] Example 1

[0057] In order to verify whether the pretreatment has an effect on the detection of ammonia nitrogen content, about 1 mg / L ammonium chloride solution (the pH of the ammonium chloride solution is 6 at this time) was prepared to detect the ammonia nitrogen content, and then the pH was adjusted to 8.5 for re-detection, and four groups of pH-adjusted solutions (10 ml in each group) were sealed and heated in a 60°C water bath for 10 min, 20 min, 30 min, and 40 min to detect the ammonia nitrogen content. The results are shown in Table 1.

[0058] From the data in Table 1 below, it can be seen that by adjusting the solution pH and heating, the ammonia nitrogen content tends to decrease as the heating time increases, especially when the heating time is more than 30 minutes, the error is large because the ammonium ion is easy to volatilize when the alkalinity increases and the heating condition is heated. However, the relative error within 20 minutes of heating is still within 2.5%. Adjusting the pH to 8.5 and heating within 10 minutes has the least effect on the detection of ammonia nitrogen content.

[0059] Table 1 Test results

[0060] Ammonia nitrogen content (g / L) pH = 6 1.0079 pH=8.5 1.0066 pH 8.5, heating for 10 minutes 1.0009 pH 8.5, heating for 20 minutes 0.9865 pH 8.5, heating for 30 minutes 0.9134 pH 8.5, heating for 40 min 0.8456

[0061] Example 2

[0062] Example 2 The method provided by the present invention is used to determine the content of ammonia nitrogen in the ammonia nitrogen simulation solution prepared with distilled water, wherein the ammonia nitrogen concentration in the ammonia nitrogen simulation solution is 1 mg / L, and the total vanadium concentration in the ammonia nitrogen simulation solution is set to 30, 50, and 90 g / L (according to V 2 O 5 The results are shown in Table 2 below. The results show that the vanadium concentration does not affect the detection of the ammonia nitrogen content in the solution, and the relative error does not exceed 3%.

[0063] Table 2 Test results

[0064]

[0065] Example 3

[0066] Example 3 The ammonia nitrogen content in a vanadium-containing solution prepared with 98% pure ammonium metavanadate was measured using the method provided by the present invention. 18 g of 98% pure ammonium metavanadate raw material was dissolved in 100 ml of 84 g / L NaOH solution. 4 + Ammonia gas is easily generated and released when the alkalinity is high, so after heating at 90℃ for 1h and cooling, a certain amount of ammonium chloride is added to verify the accuracy of the experiment. After removing ammonia at 90℃ for 1h, the ammonia nitrogen content detected by this method is 0.22g / L. When ammonium chloride is added at room temperature, the ammonia nitrogen content in the solution is 1.22g / L, 2.22g / L, 3.22g / L, and 5.22g / L respectively. The results show that the maximum error does not exceed 3%.

[0067] Table 3 Test results

[0068] Theoretical ammonia nitrogen concentration (g / L) Measured ammonia nitrogen concentration (g / L) Relative error 1.22 1.20 1.6％ 2.22 2.19 1.4％ 3.22 3.18 1.2％ 5.22 5.10 2.3％

[0069] Example 4

[0070] The vanadium-containing solution used for the test in Example 4 was taken from the experimental group of the effect of heating time on ammonia nitrogen content during the experiment in Example 3. 18g of 98% pure ammonium metavanadate raw material was dissolved in 100ml 84g / L NaOH solution, and then divided into four groups of experiments, and samples were taken after heating for 0min, 20min, 40min, and 60min respectively, and the ammonia nitrogen content was detected by the method of the present invention and the distillation method (the distillation method detects the ammonia nitrogen content by releasing the ammonia nitrogen in the solution by distillation, and then absorbing the released ammonia nitrogen with an absorbent such as boric acid solution, and finally measuring the amount of ammonia nitrogen absorbed by titration or colorimetry, thereby calculating the ammonia nitrogen content in the original solution). The results show that the ammonia nitrogen content measured by the distillation method and the method of the present invention is similar, and the relative standard deviation does not exceed 3%.

[0071] Table 4 Test results

[0072]

[0073]

[0074] Example 5

[0075] The vanadium-containing solution used in Example 5 was taken from the experimental group of the effect of heating temperature on ammonia nitrogen content during the experiment of Example 3. 18g of 98% pure ammonium metavanadate raw material was dissolved in 100ml 84g / L NaOH solution, and then the prepared samples were divided into three groups of experiments, reacted at 70°C, 80°C, and 90°C for 1h, and then samples were taken. The ammonia nitrogen content was detected by the method of the present invention and the distillation method. The results showed that the ammonia nitrogen content measured by the distillation method and the method of the present invention was similar, and the relative standard deviation did not exceed 4%.

[0076] Table 5 Test results

[0077]

[0078] Example 6

[0079] The vanadium-containing solution used in Example 6 was taken from the experimental group of the effect of the amount of alkali added on the ammonia nitrogen content during the experiment of Example 3. 18g of 98% pure ammonium metavanadate raw material was dissolved in 100ml of NaOH solution and reacted at 90°C for 1h. The experiment was divided into three groups, in which the concentrations of NaOH were 68g / L, 74g / L, and 84g / L respectively. Sampling was performed and the ammonia nitrogen content was detected by the method of the present invention and the distillation method. The results showed that the ammonia nitrogen content measured by the distillation method and the method of the present invention was similar, and the relative standard deviation did not exceed 5%.

[0080] Table 6 Test results

[0081]

[0082]

[0083] It can be seen from the above embodiments that the method provided by the present invention is simple to operate, and the results are accurate and the data are reliable.

[0084] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific implementation", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0085] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for detecting the ammonia nitrogen content in a vanadium-containing solution, characterized in that: include: (1) pre-treating the vanadium-containing solution to obtain a colorless vanadium-containing solution treatment solution, wherein the pre-treatment comprises adjusting the pH value of the vanadium-containing solution to 8 to 9 and heating the solution at 40 to 65 degrees Celsius; (2) filtering the vanadium-containing solution treatment liquid to obtain a purified liquid, and selectively diluting the purified liquid according to its concentration to obtain a diluted liquid; (3) uniformly mixing the solution obtained in step (2) with ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent, using ammonia-free water as a reference reagent, and measuring the absorbance of the solution at a wavelength of 420 nm; Based on the absorbance value, the ammonia nitrogen content in the vanadium-containing solution to be tested is calculated in combination with a standard curve; The standard curve is obtained by uniformly mixing ammonia nitrogen standard solution, ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent, placing the mixture in a fixed state, using ammonia-free water as a reference reagent, and measuring the absorbance at a wavelength of 420 nm.

2. The method according to claim 1, characterized in that The heating time in step (1) does not exceed 20 minutes.

3. The method according to claim 1, characterized in that The filtration treatment in step (2) is performed using a 0.22 micron filter membrane.

4. The method according to claim 1, characterized in that The ammonia nitrogen standard solution is prepared by dissolving ammonium chloride dried to a constant weight in pure water and then continuously diluting the solution. The mass volume ratio of the ammonium chloride to the pure water is 0.382 g:100 ml.

5. The method according to claim 1, characterized in that The concentration of the sodium hydroxide solution is 200-400 g / L, and the concentration of the potassium sodium tartrate solution is 400-600 g / L.

6. The method according to claim 1, characterized in that The standard curve was prepared by the following method: Take a series of different volumes of ammonia nitrogen standard solution in a 100ml volumetric flask, add ammonia-free water to 75ml, then add 2ml potassium sodium tartrate solution, 3ml sodium hydroxide solution and 2ml Nessler's reagent to dilute to the scale with ammonia-free water, and shake well. After leaving for 10 minutes, measure the absorbance at a wavelength of 420nm with ammonia-free water as a reference to obtain a standard curve.

7. The method according to claim 6, characterized in that The ammonia nitrogen standard solution is prepared by dissolving 0.382 g of ammonium chloride dried to constant weight in 100 ml of pure water and then diluting it 100 times. The volumes of the ammonia nitrogen standard solution are 1 ml, 5 ml, 10 ml, 15 ml, and 20 ml, respectively.

8. The method according to claim 6, characterized in that The concentration of the sodium hydroxide solution is 320 g / L, and the concentration of the potassium sodium tartrate solution is 500 g / L.

9. The method according to claim 6, characterized in that The concentration range of the standard curve is 0.1-2 mg / L.

10. A method for detecting the ammonia nitrogen content in a vanadium-containing solution, characterized in that: include: (1) pre-treating the vanadium-containing solution to obtain a colorless vanadium-containing solution treatment solution, wherein the pre-treatment comprises adjusting the pH value of the vanadium-containing solution to 8 to 9 and heating the solution at 40 to 65 degrees Celsius for no more than 20 minutes; (2) filtering the vanadium-containing solution treatment liquid to obtain a purified liquid; (3) diluting the purified liquid to obtain a diluted liquid; (4) mixing the diluent, ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent uniformly, using ammonia-free water as a reference reagent, and measuring the absorbance of the solution at a wavelength of 420 nm; Based on the absorbance value, the ammonia nitrogen content in the vanadium-containing solution is calculated in combination with a standard curve; The standard curve is obtained by mixing ammonia nitrogen standard solution and ammonia-free water, potassium sodium tartrate solution, sodium hydroxide solution and Nessler's reagent evenly, placing the mixture in a fixed state, using ammonia-free water as a reference reagent, and measuring the absorbance at a wavelength of 420 nm. The concentration range of the standard curve is 0.1 to 2 mg / L. The concentration of the sodium hydroxide solution is 320 g / L, and the concentration of the potassium sodium tartrate solution is 500 g / L.

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