CN106855504B - Method for rapidly determining sulfate radical content - Google Patents
Method for rapidly determining sulfate radical content Download PDFInfo
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- CN106855504B CN106855504B CN201610976826.0A CN201610976826A CN106855504B CN 106855504 B CN106855504 B CN 106855504B CN 201610976826 A CN201610976826 A CN 201610976826A CN 106855504 B CN106855504 B CN 106855504B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
Abstract
The invention discloses a method for rapidly determining sulfate radical content so as to provide H+And acid solution and Arabic gum solution except anion capable of combining with barium ion to generate precipitate are used as stabilizers, and the stabilizers and barium chloride particles are added into a sample to be measured to measure the light absorption value. The method for measuring the sulfate radical content has simple and convenient operation steps, easily controlled detection conditions, good linear relation and good repeatability, and the sulfate radical content is less than 40 mg/L; the method is suitable for samples with low sulfate radical content, and can also be used for detecting samples with the sulfate radical content of more than 40mg/L by diluting; the invention ensures the good determination precision and accuracy with low detection cost under the condition of no advanced precise equipment, has a correlation coefficient of 99.9 percent and high detection efficiency, and provides a reliable method suitable for determining the sulfate radical content of batch samples for laboratories.
Description
Technical Field
The invention relates to a detection method, in particular to a method for rapidly determining sulfate radical content.
Background
The conventional methods for measuring sulfate radicals include ion chromatography, barium sulfate gravimetric method, turbidimetry, volumetric method, barium chromate spectrophotometry and the like. The ion chromatography needs large instruments, the cost is high, and a plurality of laboratories cannot be equipped with the ion chromatography; the classical gravimetric method is complex to operate and low in detection efficiency; the detection condition of the turbidimetric method in the national standard is strict, the linearity is poor, and the repeatability is poor; the volumetric method is time-consuming to operate, the ammonia liquid used has pungent smell, and Ca in the sample2+、Mg2+High content can affect the accurate determination of sulfate radical; the operations of heating, pH value adjustment, filtering and the like in the barium chromate photometry are complicated and time-consuming, have large errors, meet the beer law within the sulfate radical content of 8-120 mg/L, and are not suitable for samples with low sulfate radical content. In order to ensure that the sulfate radical content is accurately and efficiently determined, the existing research provides a lot of improvements on a turbidimetric method and a barium chromate spectrophotometry method. For example, in the barium sulfate turbidimetry, stabilizers such as gelatin and PVA are used for replacing a mixed stabilizer of glycerol and ethanol in the national standard; the filtration of the barium chromate photometry was modified by centrifugation to remove the precipitate. However, the above improvements do not completely address the turbidimetric linear relationshipPoor detection result, unstable detection result, complicated operation of a barium chromate photometry, inapplicability to a sample with low sulfate radical content and the like. So far, for laboratories not equipped with advanced precision instruments, there is still no suitable method for accurately and efficiently determining different samples with high and low sulfate radical content.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Disclosure of Invention
Aiming at the technical problems, the method for measuring the sulfate radical content is simple and convenient in operation steps, easy in control of detection conditions, good in linear relation, good in repeatability, accurate and efficient in detection result, large in linear range and capable of enabling the sulfate radical content to be less than 40mg/L and meeting the beer law. The sample with low content of sulfate radical can be directly measured, and the sample with high content of sulfate radical can also be measured after dilution, so the invention has wide application range.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a method for quickly determining the content of sulfate radicals in order to provide H+And acid solution and Arabic gum solution except anion capable of combining with barium ion to generate precipitate are used as stabilizers, and the stabilizers and barium chloride particles are added into a sample to be measured to measure the light absorption value.
The method for determining the sulfate content as described above comprises the following steps:
(1) taking a sample to be tested, and sequentially adding H+And acid solution, arabic gum solution and barium chloride particles except anion capable of combining with barium ions to generate precipitates are shaken for 5-6 times to obtain a sample to be detected, and the sample is kept stand for 15 min; wherein the water is deionized water newly prepared in the same day;
(2) repeating the operation of the step (1), replacing the sample to be detected with water, obtaining a blank sample with the same others, and standing for 15 min; wherein the water is deionized water newly prepared in the same day;
(3) and (3) zeroing the blank sample obtained in the step (2) at the specific wavelength of 420nm, and measuring the light absorption value of the sample to be measured obtained in the step (1).
Wherein the mass ratio of the sample to be detected in the step (1) to the nitric acid solution, the Arabic gum solution and the barium chloride particles is 5-25: 0.25-1: 0.15-0.8.
Wherein, the mass ratio of the sample to be detected in the step (1) to the nitric acid solution, the Arabic gum solution and the barium chloride particles is 25:0.5:0.5: 0.2.
Wherein, the said can provide H+And the acid solution except that the anion can be combined with the barium ion to generate the precipitate is one of nitric acid solution, hydrochloric acid solution and acetic acid solution.
Wherein the volume concentration of the nitric acid solution, the hydrochloric acid solution or the acetic acid solution is 0.2-5%.
Wherein the pH value of the sample to be detected is 2-6.
Wherein, the mass concentration of the arabic gum solution is 0.1-1%, and the dosage is 0.2-5 mL.
Wherein the mass concentration of the arabic gum solution is 0.5%.
Wherein the particle size of the barium chloride particles is 0.25-1 mm.
Compared with the prior art, the invention has the following beneficial effects:
(1) the method for measuring the sulfate radical content has simple and convenient operation steps, easily controlled detection conditions, good linear relation and good repeatability, and the sulfate radical content is less than 40 mg/L;
(2) the method is suitable for samples with low sulfate radical content, and can also be used for detecting samples with the sulfate radical content of more than 40mg/L by diluting;
(3) the method has wide applicability, can detect nearly one hundred samples in half a working day, and is a suitable method for detecting the sulfate radical content of batch samples in a laboratory;
(4) the invention ensures the good determination precision and accuracy with low detection cost under the condition of no advanced precise equipment, has a correlation coefficient of 99.9 percent and high detection efficiency, and provides a reliable method suitable for determining the sulfate radical content of batch samples for laboratories.
Detailed Description
The following detailed description is to be read in connection with specific embodiments, but it should be understood that the scope of the invention is not limited to the specific embodiments. Collection and processing of samples used in the examples: the atmospheric precipitation of 1 ~ 7 sampling points of Guangxi friendship forest ecosystem location observation research station stay volt ripples laboratory farm, 1 water sample is respectively got to 7 sampling points, and the water sample serial number is with the sampling point number, and 1 sampling point water sampling 1 promptly, 2 sampling point water sampling 2 analogize with this. And storing the sample in a 0-4 ℃ refrigerated cabinet as a water sample to be detected. The method is applicable to detection of sulfate radicals in other solutions besides water samples.
1. Nitric acid solution: pipette the required amount of nitric acid (HNO)3Analytically pure, cheap chemical reagent limited company in Lianjiang city), adding deionized water to prepare the product;
2. gum arabic solution: weighing acacia gum (analytically pure, Chengdu Jinshan chemical reagent Co., Ltd.;) with required dosage, adding deionized water, heating and boiling until the acacia gum is dissolved, cooling and standing overnight for use; the acacia gum solution can be stored at normal temperature for more than 2 weeks in a sealed manner, if turbid, transparent gum blocks or mildew spots appear in a reagent bottle, the preparation is discarded and the gum is reconstituted;
3. 0.1mg/mL sulfate standard: 1.4788g of anhydrous sodium sulfate (Na) dried at 105 ℃ are weighed2SO4Analytically pure, Tianjin Bodi chemical Co., Ltd.) was dissolved in water to a constant volume of 1L to prepare a sulfate standard solution of 1mg/m L/volume. Extracting 10mL, adding deionized water to a constant volume of 100m L to obtain 0.1mg/mL sulfate radical standard solution;
4. barium chloride particles (BaCl)2Analytically pure, chengdu chemical reagent factory): grinding barium chloride, pouring the barium chloride onto a combined sieve (18-mesh sieve and 60-mesh sieve), and sieving to obtain crystal grains with the grain size of 0.25-1 mm;
the reagents are all of analytical grade and are all sold in the market;
5. a balance;
6. a temperature-adjusting electric furnace;
7. 722 a spectrophotometer;
8. an oven;
9. 18-mesh standard sieve;
10. a 60-mesh standard sieve;
11. deionized water.
Nitric acid (HNO) as mentioned above3Analytically pure), gum arabic (analytically pure), anhydrous sodium sulfate (Na)2SO4Analytically pure), barium chloride particles (BaCl)2Analytically pure) were purchased from glass instruments ltd, sinx, south ning.
Example 1
A method for rapidly determining sulfate radical content comprises the following operation steps:
(1) extracting 25mL of supernatant liquid of a water sample to be detected 1 after standing, injecting the supernatant liquid into a 25mL colorimetric tube, and adding 1% nitric acid solution by volume concentration, 0.5mL acacia gum solution with mass concentration of 0.5% and 0.2g barium chloride particles with particle size of 0.25-1 mm; shaking for 5-6 times to uniformly mix all substances in the sample, adding a nitric acid solution to enable the pH value of the water sample to be detected to be 4 to obtain a sample to be detected, and standing for 15min for detection;
(2) repeating the operation of the step (1), and replacing the clear solution of the water sample 1 to be detected with deionized water: injecting 25mL of deionized water into a 25mL colorimetric tube, sequentially adding 1% nitric acid solution in volume concentration, 0.5mL Arabic gum solution in mass concentration of 0.5% and 0.2g of barium chloride particles with the particle size of 0.25-1mm, shaking for 5-6 times to uniformly mix all the substances in the solution, adding the nitric acid solution to enable the pH value of a water sample to be detected to be 4, obtaining a blank sample, standing for 15min, and detecting;
(3) and (3) zeroing the blank sample obtained in the step (2) at the wavelength of 420nm of a spectrophotometer, and measuring the light absorption value of the sample to be measured obtained in the step (1) to obtain the sample.
The sulfate radical content in the water samples 2, 3, 4, 5, 6 and 7 is determined by the same method, the steps are repeated for 6 times for each water sample to be determined, the average value of the light absorption values obtained by measurement is taken, and the obtained data are shown in table 1.
Example 2
A method for rapidly determining sulfate radical content comprises the following operation steps:
(1) extracting 25mL of supernatant liquid of a water sample to be detected 1 after standing, injecting the supernatant liquid into a 25mL colorimetric tube, and adding 0.2% hydrochloric acid solution in volume concentration, 0.1mL of Arabic gum solution in mass concentration of 1% and 0.2g of barium chloride particles with the particle size of 0.25-1 mm; shaking for 5-6 times to uniformly mix the substances in the sample, adding a hydrochloric acid solution to enable the pH value of the water sample to be detected to be 2 to obtain a sample to be detected, and standing for 15min for detection;
(2) repeating the operation of the step (1), and replacing the clear solution of the water sample 1 to be detected with deionized water: injecting 25mL of deionized water into a 25mL colorimetric tube, sequentially adding a hydrochloric acid solution with the volume concentration of 0.2%, 0.1mL of Arabic gum solution with the mass concentration of 1% and 0.2g of barium chloride particles with the particle size of 0.25-1mm, shaking for 5-6 times to uniformly mix all the substances in the solution, adding a hydrochloric acid solution to enable the pH value of a water sample to be detected to be 2, obtaining a blank sample, standing for 15min, and detecting;
(3) and (3) zeroing the blank sample obtained in the step (2) at the wavelength of 420nm of a spectrophotometer, and measuring the light absorption value of the sample to be measured obtained in the step (1) to obtain the sample.
Repeating the above steps for 6 times, and taking the average value of the measured light absorption values.
Example 3
A method for rapidly determining sulfate radical content comprises the following operation steps:
(1) extracting 25mL of supernatant liquid of a water sample to be detected 1 after standing, injecting the supernatant liquid into a 25mL colorimetric tube, and adding 5% by volume of acetic acid solution, 5mL of 0.1% by mass of Arabic gum solution and 0.2g of barium chloride particles with the particle size of 0.25-1 mm; shaking for 5-6 times to uniformly mix all substances in the sample, adding an acetic acid solution to make the pH value of the water sample to be detected 6 to obtain a sample to be detected, and standing for 15min for detection;
(2) repeating the operation of the step (1), and replacing the clear solution of the water sample 1 to be detected with deionized water: injecting 25mL of deionized water into a 25mL colorimetric tube, sequentially adding 5% by volume of acetic acid solution, 5mL of Arabic gum solution with the mass concentration of 0.1% and 0.2g of barium chloride particles with the particle size of 0.25-1mm, shaking for 5-6 times to uniformly mix all the substances in the solution, adding the acetic acid solution to enable the pH value of a water sample to be detected to be 6, obtaining a blank sample, standing for 15min, and detecting;
(3) and (3) zeroing the blank sample obtained in the step (2) at the wavelength of 420nm of a spectrophotometer, and measuring the light absorption value of the sample to be measured obtained in the step (1) to obtain the sample.
Repeating the above steps for 6 times, and taking the average value of the measured light absorption values.
Establishment of a Standard Curve
0, 0.5, 1, 2, 4, 8 and 10mL of sulfate radical standard solution with the concentration of 0.1mg/mL is extracted and respectively injected into 7 colorimetric tubes, and the deionized water is subjected to constant volume to 25mL, so that a standard solution series with the sulfate radical content of 0, 0.05, 0.1, 0.2, 0.4, 0.8 and 1mg is obtained. Respectively adding 0.25mL of nitric acid solution with volume concentration of 1%, 0.5mL of Arabic gum with mass concentration of 0.5% and 0.2g of barium chloride particles with particle size of 0.25-1mm in sequence, shaking up and down for 5-6 times, adding the nitric acid solution to enable the pH value of the standard solution to be 4, standing for 15min, and measuring the light absorption value at the wavelength of 420nm of a spectrophotometer. And (3) zeroing the spectrophotometer by using the standard solution with the sulfate radical content of 0mg, measuring the light absorption values of other standard solutions, and establishing a regression equation of the sulfate radical content and the light absorption values according to the measurement result for calculating the sulfate radical content of the sample.
W＝(k×A+b)/V×1000
W: sulfate content mg/L;
k: slope of the standard curve (regression equation);
a: the light absorption value of the sample to be detected;
b: intercept of the standard curve (regression equation);
v: extracting the volume mL of the solution to be detected;
1000: a unit conversion factor.
Experiment of accuracy
And extracting 0, 0.5, 1, 1.5, 2 and 6mL of sulfate radical standard solution with the concentration of 0.1mg/mL, respectively injecting into 6 colorimetric tubes, and diluting the volume of deionized water to 25mL to obtain standard solutions with the sulfate radical contents of 0, 2, 4, 6, 8 and 24 mg/L. Respectively and sequentially adding 0.25mL of nitric acid with the volume concentration of 1%, 0.5mL of Arabic gum solution with the mass concentration of 0.5% and 0.2g of barium chloride particles with the particle size of 0.25-1mm, shaking up and down for 5-6 times, enabling the pH value of the solution to be detected to be 4 by adding the nitric acid solution, standing for 15min, and then measuring the light absorption value at the wavelength of 420nm of a spectrophotometer. And (4) zero-setting the spectrophotometer by using the standard solution with the sulfate radical content of 0mg, and then measuring the light absorption values of the solutions with the sulfate radical contents of 2, 4, 6, 8 and 24 mg/L. The sulfate content was calculated from the regression equation obtained in the above standard curve building process, the above experiment was repeated 6 times, the average of the obtained measured values was taken, and the obtained data are shown in table 2.
Table 1 precision test of method for rapid determination of sulfate content
As can be seen from Table 1, the sulfate content of samples 1, 2 and 3 is low, less than 5mg/L, SD (standard deviation) is less than 0.3, and CV (coefficient of variation) of the sulfate content is less than 10%; samples 4, 5, 6, 7 had sulfate contents between 5-11mg/L, SD less than 0.5, and CV of sulfate content less than 5%. Samples 6, 7 had sulfate content between 20-40mg/L, SD less than 1.5, and sulfate content CV less than 5%. Therefore, the detection method provided by the invention can ensure small dispersion of detection results and good precision for samples with sulfate radical content less than 5mg/L and sulfate radical content between 5mg/L and 40 mg/L. The method for rapidly determining the sulfate radical content provided by the invention has the advantage that the precision can meet the detection requirements of samples with different sulfate radical contents.
TABLE 2 method for the rapid determination of sulfate radical content
As can be seen from Table 2, the recovery rate of the method of the present invention is between 95% and 104%, and the RSD (relative standard deviation) is between 2% and 5%, which shows that the method of the present invention has high accuracy and small deviation in measuring the sulfate radical content. Therefore, the method for rapidly determining the sulfate radical content has good precision and accuracy, and meets the laboratory detection requirements.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (8)
1. A method for rapidly determining sulfate radical content is characterized in that: to be able to provide H+Acid solution and Arabic gum solution except anion capable of combining with barium ion to generate precipitate are used as stabilizers, and the stabilizers and barium chloride particles are added into a sample to be measured to measure the light absorption value; wherein said can provide H+And the acid solution except that the anion can be combined with the barium ion to generate precipitation is one of nitric acid solution, hydrochloric acid solution and acetic acid solution; the mass ratio of the sample to be detected to the nitric acid solution, the Arabic gum solution and the barium chloride particles is 5-25: 0.25-1: 0.15-0.8.
2. The method for rapidly determining the sulfate content according to claim 1, which is characterized in that the method for rapidly determining the sulfate content comprises the following operation steps:
(1) taking a sample to be tested, and sequentially adding H+And acid solution, arabic gum solution and barium chloride particles except anion which can be combined with barium ions to generate precipitates are shaken to obtain a sample to be tested, and then the sample is kept stand;
(2) repeating the operation of the step (1), replacing the sample to be detected with water, obtaining a blank sample with the same others, and standing;
(3) and (3) zeroing the blank sample obtained in the step (2) at a specific wavelength, and measuring the light absorption value of the sample to be measured obtained in the step (1).
3. The method for rapidly determining sulfate content according to claim 2, wherein: and (2) the mass ratio of the sample to be detected to the nitric acid solution, the Arabic gum solution and the barium chloride particles in the step (1) is 25:0.5:0.5: 0.2.
4. The method for rapidly determining sulfate content according to claim 1, wherein: the volume concentration of the nitric acid solution, the hydrochloric acid solution or the acetic acid solution is 0.2-5%.
5. The method for rapidly determining sulfate content according to claim 1 or 2, wherein: the pH value of the sample to be detected is 2-6.
6. The method for rapidly determining sulfate content according to claim 1 or 2, wherein: the mass concentration of the arabic gum solution is 0.1-1%, and the dosage is 0.2-5 mL.
7. The method for rapidly determining sulfate content according to claim 1 or 2, wherein: the mass concentration of the arabic gum solution is 0.5%.
8. The method for rapidly determining sulfate content according to claim 1 or 2, wherein: the particle size of the barium chloride particles is 0.25-1 mm.
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| RU2681855C1 (en) * | 2017-09-15 | 2019-03-13 | Общество С Ограниченной Ответственностью "Агронэт" | Method for determining sulfur in form of sulfate ion in water soil extract and device for implementing method |
| CN112924400A (en) * | 2019-12-05 | 2021-06-08 | 中粮生物科技股份有限公司 | Method for detecting sulfate content in citric acid sample |
| CN115667151B (en) * | 2020-05-27 | 2024-03-12 | 松下知识产权经营株式会社 | Barium compound structure and method for producing same |
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| US3622277A (en) * | 1969-12-29 | 1971-11-23 | Betz Laboratories | Method for determining sulfate concentration |
| US8178353B2 (en) * | 2007-05-31 | 2012-05-15 | General Electric Company | Method for determination of polymer concentration in water systems |
| CN105388121A (en) * | 2015-12-29 | 2016-03-09 | 瓮福达州化工有限责任公司 | Detection method for sulfate radical in load solvent |
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| "杂项"光度法测定无水硝中硫酸根含量;张桂香 等;《中国井矿盐》;20031125;第34卷;第40-42页 * |
| 吸光比浊法测定硝酸钴溶液中硫酸根;张科翠 等;《冶金分析》;20131115;第33卷(第11期);第63-66页 * |
| 紫外分光光度法直接测定常量硫酸根;詹文毅 等;《理化检验-化学分册》;20160218;第52卷;第159-162页 * |
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