Quantitative detection method for nitrate radicals in tin hydroxide sample and application of quantitative detection method

Abstract

The invention discloses a quantitative detection method for nitrate radicals in a tin hydroxide sample and application thereof, and belongs to the technical field of chemical analysis, and the method comprises the following steps: water extraction: adding 50 mL of deionized water into a tin hydroxide sample to be detected, uniformly mixing, carrying out ultrasonic treatment at 50 DEG C for 15 min, cooling to room temperature, transferring the mixture into a 200 mL or 500 mL volumetric flask, adding deionized water to a scale line, and carrying out water extraction; obtaining a mixture; solid-liquid separation: filtering the mixture through a 0.45-micron filter membrane of a diaphragm vacuum pump to obtain a clarified extract; and ion chromatography detection: injecting the extract liquor into an anion exchange chromatographic column of an ion chromatograph, and quantitatively detecting nitrate radicals through a suppression type conductivity detector. The pretreatment is simple, and the detection is high-throughput and automatic; the sensitivity is high, the detection limit is low, and the anti-interference performance is strong; detection data are accurate, and production process requirements are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical analysis, in particular to a quantitative detection method of nitrate in tin hydroxide sample and application thereof. BACKGROUND

[0002] At present, the detection methods of nitrate at home include ultraviolet spectrophotometry, cadmium column reduction colorimetry, nitro disulfonic acid colorimetry, reduction-azo spectrophotometry, Raman spectroscopy and ion chromatography, wherein: The ultraviolet spectrophotometry is easy to be interfered by organic matter, and the matrix effect is significant; the cadmium column reduction colorimetry is suitable for low content nitrate detection (0-300 ppm), and cannot well exclude the interference of the matrix, and the cadmium column is toxic and not environmentally friendly; the nitro disulfonic acid colorimetry is difficult to exclude the interference of chloride ions, resulting in large error of the result. The Raman spectroscopy is expensive in equipment, and the detection limit is high, and the anti-interference ability is insufficient.

[0003] In addition, the commonly used methods for dissolving the sample in powder or solid sample include acid dissolution method, alkali dissolution method and melting method, wherein: The concentrated acid in the acid dissolution method can cause the decomposition of nitrate, and the sample needs to be neutralized and purified after dissolution, and the dissolution process can introduce interfering ions such as Na+ and Cl-, which need subsequent treatment; the alkali in the alkali dissolution method can easily destroy inorganic nitrate, and the temperature and time need to be strictly controlled; the melting method can process the insoluble matrix, but has thermal instability, and the steps are complicated and the recovery rate of nitrate is low.

[0004] Therefore, how to develop a quantitative detection method of nitrate in tin hydroxide sample and application thereof is a technical problem to be solved by the person skilled in the art. SUMMARY

[0005] Therefore, the present application provides a quantitative detection method of nitrate in tin hydroxide sample and application thereof.

[0006] In order to achieve the above purpose, the present application adopts the following technical scheme: A method for analyzing nitrate in a tin hydroxide sample, comprising the following steps: (1) Water extraction: mix and stir 50 mL of deionized water with the tin hydroxide sample to be measured, ultrasonically treat at 50℃ for 15 min, cool to room temperature, and transfer the mixture to a 200 mL or 500 mL volumetric flask, add deionized water to the calibration line to obtain a mixture; (2) Solid-liquid separation: filter the mixture obtained in step (1) through a 0.45 um filter membrane of a diaphragm vacuum pump to obtain a clear extraction solution; (3) Ion chromatography detection: inject the extraction solution obtained in step (2) into an anion exchange chromatographic column of an ion chromatograph, and quantitatively detect the nitrate by an suppressor conductivity detector.

[0007] Further, in step (1), the resistivity of the deionized water is ≥18.2 MΩ·cm; the ultrasonic treatment uses an ultrasonic oscillator, and the ultrasonic frequency is 40 kHz.

[0008] Further, in step (2), the filter membrane is made of polyether sulfone.

[0009] Further, in step (3), the ion chromatography system detection conditions are as follows: The chromatographic column is an anion exchange column, Metrosep A Supp 5-250 / 4.0. The mobile phase is a mixed solution of Na2CO3 and NaHCO3, wherein the concentration of Na2CO3 is 3.2 mmol / L, the concentration of NaHCO3 is 1.0 mmol / L, and the concentration of concentrated H2SO4 solution is 5‰. The injection volume is 20 μL. The flow rate is 0.7 mL / min. The column temperature is 40°C.

[0010] Further, step (3) further comprises drawing a working curve of the nitrate standard solution with different concentrations, and calculating the concentration of nitrate in the tin hydroxide sample to be measured based on the working curve.

[0011] Further, the content of nitrate in the tin hydroxide sample to be measured is calculated according to the following formula: ω=C×V×10 -4 / m; In the formula, C is the concentration of nitrate in the tin hydroxide sample to be measured, µg / mL. V is the preparation volume of the water extraction of the tin hydroxide sample to be measured, mL. m is the sample weight, g.

[0012] Further, the working curve is drawn by the following method: 1) Respectively, 0.0 mL, 1.0 mL, 6.0 mL, 10.0 mL of nitrate standard solution with a nitrate concentration of 50 µg / mL and 2.0 mL, 5.0 mL of nitrate standard solution with a nitrate concentration of 500 µg / mL are transferred into a group of 100 mL volumetric flasks, deionized water is added to the calibration line, and shaken uniformly; 2) The standard solution obtained in step 1) is injected into the anion exchange chromatographic column of the ion chromatograph, and the nitrate is quantitatively detected by the suppressor conductivity detector. After the injection is completed, the nitrate standard curve is drawn, and the ion chromatography system detection conditions are the same as the tin hydroxide sample ion chromatography system detection conditions.

[0013] Further, the nitrate standard solution with a nitrate concentration of 500 µg / mL and 50 µg / mL is prepared by the following method: Accurately weigh 0.8153 g of potassium nitrate into a 100 mL beaker, add deionized water to dissolve, then transfer to a 1000 mL volumetric flask, dilute to the mark with deionized water, shake well, and obtain a nitrate standard solution with a nitrate concentration of 500 µg / mL; Accurately take 10.0 mL of the obtained nitrate standard solution with a concentration of 500 µg / mL into a 100 mL volumetric flask, dilute to the mark with deionized water, shake well, and obtain a nitrate standard solution with a nitrate concentration of 50 µg / mL.

[0014] The application also provides an application of the method in the evaluation of the content of nitrate in electronic-grade tin hydroxide material or the detection of nitrate in tin material.

[0015] Compared with the prior art, the application has the following beneficial effects: 1. Based on existing experimental equipment, simple pretreatment, high-throughput automation of detection; 2. High sensitivity and low detection limit, strong anti-interference; 3. Accurate detection data, meeting the requirements of production process; the determination range of nitrate content is 0.002%-12%, the detection limit is 0.0011 µg, and the quantification limit is 0.0037 µg. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The working curve graph of the nitrate standard solution for the embodiment of the application is drawn.

[0017] Figure 2 The flowchart of the determination method of the content of nitrate in tin hydroxide for the embodiment of the application is drawn.

[0018] Figure 3 The flowchart of the determination method of the content of nitrate in tin hydroxide for the embodiment of the application is drawn. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0020] The deionized water used in the embodiments of the application has a resistivity of ≥18.2 MΩ·cm.

[0021] The instrument used in the embodiments of the application is: Ion chromatograph (company: Swiss Metrohm, model: 883 Basic IC Plus); The vacuum pump used is a diaphragm vacuum pump (company model: GM-0.33A). The ultrasonic oscillator is an ultrasonic machine (Jiemeng model: JP-031).

[0022] Example 1 The analytical method for nitrate ions in tin hydroxide samples includes the following steps: (1) Nitrate standard solutions with nitrate concentrations of 500 µg / mL and 50 µg / mL were prepared by the following method: Accurately weigh 0.8153 g of potassium nitrate (potassium nitrate dried at 105℃ for 1 h, spectrally pure) into a 100 mL beaker, add deionized water to dissolve it, transfer it to a 1000 mL volumetric flask, dilute with deionized water to the mark, and shake well to obtain a nitrate standard solution with a nitrate concentration of 500 µg / mL. Accurately transfer 10.0 mL of the obtained nitrate standard solution with a concentration of 500 µg / mL into a 100 mL volumetric flask, dilute to the mark with deionized water, and shake well to obtain a nitrate standard solution with a nitrate concentration of 50 µg / mL.

[0023] (2) The working curve is plotted using the following method: 1) Transfer 0.0 mL, 1.0 mL, 6.0 mL, and 10.0 mL of nitrate standard solution with a nitrate concentration of 50 µg / mL, and 2.0 mL and 5.0 mL of nitrate standard solution with a nitrate concentration of 500 µg / mL, respectively, into a set of 100 mL volumetric flasks, add deionized water to the mark, and shake well; 2) Inject the standard solution obtained in step 1) into the anion exchange column of the ion chromatograph. Quantitatively detect nitrate using a suppressed conductivity detector. After injection, analyze the conductivity-retention time chromatograms of standard samples with different nitrate concentrations to establish a peak area-concentration standard curve for nitrate content. Figure 1 As shown, the detection conditions of the ion chromatography system are the same as those of the ion chromatography system for the tin hydroxide sample.

[0024] Example 2 The main steps for detecting nitrate in tin hydroxide materials are as follows: 1) Water extraction: such as Figure 2 As shown, 0.5001g of the tin hydroxide sample to be tested was mixed with 50mL of deionized water and stirred with a glass rod. The mixture was then sonicated at 50℃ for 15min using an ultrasonic oscillator with an ultrasonic frequency of 40kHz. After cooling to room temperature, the mixture was transferred to a 200mL volumetric flask and deionized water was added to the mark to obtain the mixture. 2) Solid-liquid separation: The mixture obtained in step 1) is filtered through a 0.45 μm filter membrane using a diaphragm vacuum pump. The filter membrane is made of polyethersulfone, and a clear extract is obtained. 3) Ion Chromatography Detection: The extract obtained in step 2) is injected into the anion exchange column of an ion chromatograph. Nitrate is quantitatively detected using a suppressed conductivity detector. The concentration of nitrate in the tin hydroxide sample is calculated based on the working curve. The nitrate content in the tin hydroxide sample is expressed as ω, with the value expressed as a percentage (%), and is calculated using the following formula: ω=C×V×10 -4 / m; Where: C - the concentration of nitrate ions in the tin hydroxide sample to be tested, µg / mL; V - Volume of water extraction preparation of the tin hydroxide sample to be tested, mL; m - Sample weight, g.

[0025] In this example, the concentration of nitrate was determined to be 1.015 µg / mL, the preparation volume was 200 mL, and the sample weight was 0.5001 g. The calculation results are as follows: ω=1.015*200*10 -4 / 0.5001=0.0406%; Detection conditions for ion chromatography system: Chromatographic column: Anion exchange column, Metrosep A Supp 5-250 / 4.0; The mobile phase consisted of a mixed solution of Na2CO3 and NaHCO3 as the eluent, with Na2CO3 at a concentration of 3.2 mmol / L and NaHCO3 at a concentration of 1.0 mmol / L; and a 5 wt‰ H2SO4 solution as the regeneration solution. Eluent (3.2 mmol / L Na2CO3 + 1.0 mmol / L NaHCO3): Weigh 0.6784 g sodium carbonate (GR) and 0.1680 g sodium bicarbonate (GR), dissolve them in deionized water, and after complete dissolution, bring the volume to 2000 mL. Sonicate the solution for later use. Regeneration solution (5‰ H2SO4): Take 5 mL of concentrated sulfuric acid (GR 98%), slowly add it to 500 mL of deionized water, make up to 1000 mL, sonicate and set aside. Injection volume: 20 μL; Flow rate: 0.7 mL / min; Column temperature: 40℃.

[0026] Example 3 The main steps for detecting nitrate in tin hydroxide materials are as follows: 1) Water extraction: such as Figure 2As shown, 0.1011 g of the tin hydroxide sample to be tested was added to 50 mL of deionized water and stirred with a glass rod. The mixture was then sonicated at 50 °C for 15 min using an ultrasonic oscillator with an ultrasonic frequency of 40 kHz. After cooling to room temperature, the mixture was transferred to a 500 mL volumetric flask, and deionized water was added to the mark to obtain the mixture. 2) Solid-liquid separation: The mixture obtained in step (1) is filtered through a 0.45 μm filter membrane using a diaphragm vacuum pump. The filter membrane is made of polyethersulfone, and a clear extract is obtained. 3) Ion Chromatography Detection: The extract obtained in step (2) is injected into the anion exchange column of the ion chromatograph. Nitrate is quantitatively detected by a suppressed conductivity detector. The concentration of nitrate in the tin hydroxide sample is calculated based on the working curve. The nitrate content in the tin hydroxide sample is expressed as ω, and the value is expressed as a percentage (%). It is calculated using the following formula: ω=C×V×10 -4 / m; Where: C - the concentration of nitrate ions in the tin hydroxide sample to be tested, µg / mL; V - Volume of water extraction preparation of the tin hydroxide sample to be tested, mL; m - Sample weight, g.

[0027] In this example, the concentration of nitrate was determined to be 15.974 µg / mL, the preparation volume was 500 mL, and the sample weight was 0.1011 g. The calculation results are as follows: ω=30.587*500*10 -4 / 0.2014=7.90% Detection conditions for ion chromatography system: Chromatographic column: Anion exchange column, Metrosep A Supp 5-250 / 4.0; The mobile phase consisted of a mixed solution of Na2CO3 and NaHCO3 as the eluent, with Na2CO3 at a concentration of 3.2 mmol / L and NaHCO3 at a concentration of 1.0 mmol / L; and a 5 wt‰ H2SO4 solution as the regeneration solution. Eluent (3.2 mmol / L Na2CO3 + 1.0 mmol / L NaHCO3): Weigh 0.6784 g sodium carbonate (GR) and 0.1680 g sodium bicarbonate (GR), dissolve them in deionized water, and after complete dissolution, bring the volume to 2000 mL. Sonicate the solution for later use. Regeneration solution (5‰ H2SO4): Take 5 mL of concentrated sulfuric acid (GR 98%), slowly add it to 500 mL of deionized water, make up to 1000 mL, sonicate and set aside. Injection volume: 20 μL; Flow rate: 0.7 mL / min; Column temperature: 40℃.

[0028] Experimental Example 1: Effect of Leaching Conditions on Nitrate Determination To investigate the effect of different leaching conditions on nitrate determination, the same sample was selected to affect the nitrate determination results under different temperature conditions. Compared with Example 3, the comparative groups were identical in all steps and parameters except for the leaching temperature and ultrasonic decomposition time.

[0029] Table 1. Effect of different ultrasonic treatment temperatures on nitrate levels.

[0030] As shown in Table 1, under the condition of consistent ultrasonic treatment time, the measured values ​​and recovery rate are more ideal when the immersion temperature is between 50℃ and 60℃. The ultrasonic treatment temperature used in this invention is 50℃.

[0031] Table 2 Effect of different ultrasonic treatment times on nitrate levels

[0032] As shown in Table 2, under the condition of consistent leaching temperature, the measured value and recovery rate of nitrate were basically consistent when the ultrasonic decomposition time was between 15 min and 30 min. Therefore, the leaching conditions selected in this invention are a leaching temperature of 50℃ and a leaching time of 15 min.

[0033] Experimental Example 2: Limit of Detection and Limit of Quantification The detection limit determination test of this invention was performed according to conventional standards in the art, and the results are as follows: (1-1) Accurately transfer 1.0 mL of 50 µg / mL nitrate standard solution into a 500 mL volumetric flask, dilute with water to the mark, and shake well. This solution contains 0.1 µg / mL nitrate per mL.

[0034] (1-2) Take three portions of solution (1-1) and place them separately into an ion chromatography autosampler for detection. Record the signal-to-noise ratio (S / N). According to C 标 / C 噪 =H 标 / H 噪 D=3*C 噪 =3*C 标 *H 噪 / H 标 Calculate the detection limit using X=10*C 噪 =10*C 标 *H 噪 / H 标 The limits of quantitation were calculated, and the results are shown in Table 3.

[0035] Table 3 Limits of Detection and Limits of Quantification for Nitrate

[0036] Experimental Example 3: Method Precision Test Six portions of sample 1 and six portions of sample 2 were weighed. Sample 1 was prepared into a sample solution according to Example 2, and sample 2 was prepared into a sample solution according to Example 3. The nitrate content of each sample was detected and calculated according to the detection conditions of ion chromatography. The results are shown in Table 4.

[0037] Table 4. Precision test results of nitrate in samples

[0038] As shown in Table 4, the RSDs of nitrate content in the samples were 1.25% and 1.77%, respectively, indicating that this method has good precision in determining the nitrate content in tin hydroxide and can meet the determination requirements.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for the analysis of nitrate in a tin hydroxide sample, characterized in that, The method comprises the following steps: (1) water extraction: mix and stir the tin hydroxide sample to be tested with 50 mL of deionized water, treat with ultrasonic waves at 50°C for 15 min, cool to room temperature, transfer the mixture to a 200 mL or 500 mL volumetric flask, add deionized water to the calibration line, and obtain the mixture; (2) solid-liquid separation: filter the mixture obtained in step (1) through a 0.45 um filter membrane with a diaphragm vacuum pump to obtain a clear extract; (3) ion chromatography detection: inject the extract obtained in step (2) into an anion exchange chromatographic column of an ion chromatograph, and quantitatively detect nitrate by means of a suppressor conductivity detector.

2. A method of analysis of nitrate in a tin hydroxide sample according to claim 1, characterized in that, In step (1), the deionized water has a resistivity of ≥18.2 MΩ·cm; the ultrasonic treatment uses an ultrasonic oscillator, and the ultrasonic wave frequency is 40 kHz.

3. A method of analysis of nitrate in a tin hydroxide sample according to claim 1, characterized in that, In step (2), the filter membrane is made of polyether sulfone.

4. The method for analyzing nitrate in a tin hydroxide sample according to claim 1, characterized by, In step (3), the ion chromatography system detection conditions are as follows: Chromatographic column: anion exchange column, Metrosep A Supp 5-250 / 4.0; Mobile phase: a mixed solution of Na2CO3 and NaHCO3 as the eluent, wherein the concentration of Na2CO3 is 3.2 mmol / L, and the concentration of NaHCO3 is 1.0 mmol / L; a concentrated H2SO4 solution with a concentration of 5‰ as the regeneration liquid; Injection amount: 20 μL; Flow rate: 0.7 mL / min; Column temperature: 40°C.

5. A method for the analysis of nitrate in a tin hydroxide sample according to claim 1, characterized in that, Step (3) further comprises drawing a working curve of nitrate standard solutions with different concentrations, and calculating the concentration of nitrate in the tin hydroxide sample to be tested based on the working curve.

6. The method for analyzing nitrate in a tin hydroxide sample according to claim 1, wherein the content of nitrate in the tin hydroxide sample to be tested is calculated according to the following formula: wherein C is the concentration of nitrate in the tin hydroxide sample to be tested, µg / mL; V is the preparation volume of the water extract of the tin hydroxide sample to be tested, mL; and m is the sample weight, g. ω = C x V x 10 -4 / m; The working curve is drawn by the following method: 1) respectively take 0.0 mL, 1.0 mL, 6.0 mL, 10.0 mL of a nitrate standard solution with a nitrate concentration of 50 µg / mL and 2.0 mL, 5.0 mL of a nitrate standard solution with a nitrate concentration of 500 µg / mL into a group of 100 mL volumetric flasks, add deionized water to the calibration line, shake well, and obtain the standard solutions; 2) inject the standard solutions obtained in step 1) into an anion exchange chromatographic column of an ion chromatograph, quantitatively detect nitrate by means of a suppressor conductivity detector, and draw a nitrate standard curve after the injection is completed, wherein the ion chromatography system detection conditions are the same as the tin hydroxide sample ion chromatography system detection conditions.

7. A method of analysis of nitrate in a tin hydroxide sample according to claim 5, characterized in that, The nitrate standard solutions with a nitrate concentration of 500 µg / mL and 50 µg / mL are prepared by the following method: Accurately weigh 0.8153 g of potassium nitrate into a 100 mL beaker, dissolve by adding deionized water, transfer to a 1000 mL volumetric flask, dilute with deionized water to the calibration line, shake well, and obtain a nitrate standard solution with a nitrate concentration of 500 µg / mL. ​ 8. A method of analysis of nitrate in a sample of tin hydroxide according to claim 7, characterized in that, ​ ​ Accurately pipette 10.0 mL of the resulting nitrate standard solution with a concentration of 500 µg / mL into a 100 mL volumetric flask, dilute to the mark with deionized water, shake well, and obtain a nitrate standard solution with a concentration of 50 µg / mL.

9. Use of the method according to any one of claims 1 to 8 for the evaluation of the nitrate content in electronic-grade tin hydroxide material or for the detection of nitrate in tin material.

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