Method for detecting content of titanium dioxide in sample and application thereof

Abstract

The invention relates to the technical field of component content detection, in particular to a method for detecting the content of titanium dioxide in a sample and application of the method. The method for detecting the content of titanium dioxide in the sample comprises the following steps: (a) carbonizing and firing a sample to be detected to obtain a first mixed system; (b) heating a first mixture containing the first mixed system and a sulfuric acid solution to obtain a second mixed system; (c) filtering a second mixture containing the second mixed system, water and hydrogen peroxide to obtain a liquid to be detected; and (d) detecting the light absorption value of the to-be-detected liquid, and calculating the content of titanium dioxide in the to-be-detected sample according to the light absorption value. The method for detecting the content of titanium dioxide in the sample has the advantages of simplicity and convenience in operation, high accuracy, good repeatability, high safety, low cost and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of component content detection, and in particular to a method for detecting titanium dioxide content in a sample and application thereof. Background Art

[0002] Titanium dioxide is also known as titanium dioxide, and its molecular formula is TiO 2 It is a soft white powder with the characteristics of non-toxicity, stability and good dispersibility. Titanium dioxide is widely used in digestion and metabolism experiments of pigs, chickens and cattle as the currently applicable exogenous indicator. The recovery rate and distribution of the indicator have a great influence on the results of digestibility determination. Therefore, when applying the exogenous indicator method, it is necessary to ensure that the indicator is fully mixed with the feed and the fecal sample is collected evenly.

[0003] The accuracy of titanium dioxide determination determines the accuracy of digestion and metabolism tests. Methods for quantitative detection of titanium dioxide include inductively coupled plasma emission spectroscopy (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS) and diantipyrine methane colorimetry. ICP-AES and ICP-MS methods require the use of large instruments, and the sample pretreatment operations are complicated, and the elements to be determined need to be enriched. These two methods have high operating costs and require a high level of professionalism from the test personnel, making them difficult to be widely used. Laboratories that do not have large-scale detection instruments cannot use ICP-AES and ICP-MS methods. When the diantipyrine methane colorimetric method is used to determine titanium dioxide, the interference of background absorption often causes the test results to be biased high, which can easily cause large errors.

[0004] The above problems can be avoided by using spectrophotometer to determine titanium dioxide in livestock and poultry feed and chyme. This method has a high recovery rate and detection sensitivity, and titanium dioxide has stable chemical properties and is insoluble in water and dilute acid; in addition, this method has the advantages of high sensitivity, low detection limit, and wide linear range. However, the spectrophotometer method has the following problems:

[0005] 1) Weighing too little sample may result in the following errors

[0006] ① Weighing error: Weighing too little sample will increase the sensitivity of the balance during weighing. Slight vibrations or air flow changes may affect the results, leading to weighing errors.

[0007] ②Analytical error: Weighing too little sample may lead to uneven consumption of reagents during the analysis process, affecting the completeness and accuracy of the reaction, thereby affecting the analysis results.

[0008] ③ Repeatability and reproducibility errors: Weighing too little sample may result in poor repeatability and reproducibility, because the results of each weighing may vary due to changes in operating conditions, affecting the stability and reliability of the results.

[0009] There are potential risks when the muffle furnace works at high temperature for a long time. The muffle furnace working at high temperature for a long time may cause equipment damage or safety accidents.

[0010] ① Safety risk: The design of the muffle furnace does not support long-term operation at high temperatures. Long-term high-temperature operation may burn out the heating elements, so it is not recommended to use it overnight at 500°C.

[0011] ② Increase the workload of personnel: The muffle furnace works for a long time at high temperature, which is equivalent to extreme working conditions. Moreover, high temperature overnight is dangerous in itself, so people need to be on duty just in case.

[0012] In view of this, the present invention is proposed. Summary of the invention

[0013] The object of the present invention is to provide a method for detecting the content of titanium dioxide in a sample and its application. The method for detecting the content of titanium dioxide in a sample has the advantages of simple operation, high accuracy, good repeatability, high safety, low cost, etc.

[0014] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0015] One aspect of the present invention relates to a method for detecting the content of titanium dioxide in a sample, comprising the following steps:

[0016] (a) carbonizing and burning the sample to be tested to obtain a first mixed system;

[0017] (b) heating the first mixture containing the first mixed system and the sulfuric acid solution to obtain a second mixed system;

[0018] (c) filtering the second mixture containing the second mixed system, water and hydrogen peroxide to obtain a test solution;

[0019] (d) detecting the absorbance value of the test liquid, and calculating the titanium dioxide content in the test sample according to the absorbance value.

[0020] The method for detecting the titanium dioxide content in a sample has the advantages of simple operation, high accuracy, good repeatability, high safety, low cost, etc.

[0021] Another aspect of the present invention also relates to a method for detecting the digestion and metabolism level of feed, including the method for detecting the titanium dioxide content in a sample.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The method for detecting the titanium dioxide content in a sample provided by the present invention has the advantages of simple operation, high detection result accuracy, good repeatability, etc. Before detecting the titanium dioxide content, the sample to be tested is subjected to a certain pretreatment, and the pretreatment can improve the accuracy of the titanium dioxide content detection.

[0024] (2) The detection principle of the method for detecting the content of titanium dioxide in a sample provided by the present invention is: 2 It can dissolve in hot concentrated sulfuric acid to form titanyl sulfate. Titanyl sulfate reacts with H 2 O 2 It can generate a relatively stable orange-yellow [TiO(H 2 O 2 )] 2+ Within a certain concentration range, its absorbance at a wavelength of 410 nm is similar to that of TiO 2 The content is linearly related; based on this principle, a method for detecting the titanium dioxide content in the sample was designed.

[0025] (3) The method for detecting the titanium dioxide content in a sample provided by the present invention requires instruments and equipment that can be met by most laboratories. The sample pretreatment is simple and rapid, the test result recovery rate is high and the repeatability is good. It also reduces the risk of using a muffle furnace at high temperature overnight and the workload of the experimenter, and can be used for the inspection of samples in metabolic experiments.

[0026] (4) The method for detecting the titanium dioxide content in a sample provided by the present invention has a good effect in digesting feed and feces samples, and the test results have high precision and high recovery rate. It is a method for determination that is easy to operate and has accurate results, and is suitable for promotion and application in poultry metabolism tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a standard curve for determining titanium concentration provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0030] One aspect of the present invention relates to a method for detecting the content of titanium dioxide in a sample, comprising the following steps:

[0031] (a) carbonizing and burning the sample to be tested to obtain a first mixed system;

[0032] (b) heating the first mixture containing the first mixed system and the sulfuric acid solution to obtain a second mixed system;

[0033] (c) filtering the second mixture containing the second mixed system, water and hydrogen peroxide to obtain a test solution;

[0034] (d) detecting the absorbance value of the test liquid, and calculating the titanium dioxide content in the test sample according to the absorbance value.

[0035] The method for detecting the titanium dioxide content in a sample has the advantages of simple operation, high detection accuracy, good repeatability, etc. Before detecting the titanium dioxide content, the sample to be tested is subjected to a certain pretreatment, and the pretreatment can improve the accuracy of the titanium dioxide content detection; the detection principle of the method is: TiO 2 It can dissolve in hot concentrated sulfuric acid to form titanyl sulfate. Titanyl sulfate reacts with H 2 O 2 It can generate a relatively stable orange-yellow [TiO(H 2 O 2 )] 2+ Within a certain concentration range, its absorbance at a wavelength of 410 nm is similar to that of TiO 2 The content is linearly related; based on this principle, a method for detecting the titanium dioxide content in the sample was designed.

[0036] The purpose of carbonization: 1) Prevent the sample from flying due to the rapid evaporation of water in the sample due to high temperature during burning. Carbonization can reduce the rapid evaporation of water at high temperature, thereby preventing the sample from flying and ensuring the accuracy of the measurement. 2) Prevent sugar, protein, starch and other substances that are easy to foam and expand from foaming and expanding at high temperature and overflowing from the crucible. Carbonization can prevent these substances from foaming and expanding at high temperature, thereby avoiding overflowing from the crucible and ensuring the smooth progress of the ashing process. 3) Carbonization can make the organic matter in the sample fully burn, reduce the situation where carbon particles are wrapped, and reduce interference with subsequent detection. 4) At the same time, reduce the energy consumption of ashing and reduce unpleasant odors.

[0037] The main purpose of muffle furnace burning is to fully oxidize and burn the organic components in the material, leaving behind inorganic residues with more stable properties, which is more conducive to subsequent processing.

[0038] Furthermore, the sample to be tested includes but is not limited to at least one of chyme, feed or feces.

[0039] Furthermore, when the sample to be tested is chyme, 0.2-0.3 g (for example, but not limited to, any one of 0.2 g, 0.24 g, 0.26 g, 0.28 g or 0.3 g or a range between any two) of chyme is weighed for carbonization.

[0040] Furthermore, when the sample to be tested is feed, 0.7 to 0.8 g (for example, it may be but is not limited to any one of 0.7 g, 0.72 g, 0.74 g, 0.76 g, 0.78 g or 0.8 g or a range between any two of them) of feed is weighed for carbonization.

[0041] Furthermore, when the sample to be tested is feces, 0.1-0.4 g (for example, but not limited to, any one of 0.1 g, 0.2 g, 0.3 g or 0.4 g or a range between any two) of feces is weighed for carbonization.

[0042] Different samples to be tested have different sample weights. If the sample weight is not within an appropriate range, it will cause weighing errors, analysis errors, repeatability and reproducibility errors, thereby affecting the test results. The present invention provides different sample weights for different samples to be tested, accurately controls the test results from the perspective of sample weight, and reduces errors.

[0043] Furthermore, the chyme includes but is not limited to: chyme that has been freeze-dried.

[0044] The present invention does not specifically limit the type of feed, including but not limited to: any one of chicken feed, pig feed or cattle feed.

[0045] Furthermore, the carbonization temperature is 100-300°C, including but not limited to any point value of 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C or 300°C or a range value between any two of them.

[0046] If the temperature is too low, carbonization is incomplete and inorganic substances are not removed completely, which affects the stability and parallelism of the test data. In addition, smoke will come out of the muffle furnace, emitting an unpleasant odor and polluting the ambient air.

[0047] If the temperature is too high, the crucible containing the sample will explode due to local overheating, and the sample will easily overflow or float away, which will cause errors in the test data on the one hand and be unfriendly to the operator on the other.

[0048] Furthermore, the carbonization time is 0.5 to 1.5 h, including but not limited to any one of 0.5 h, 0.7 h, 0.9 h, 1.1 h, 1.3 h or 1.5 h or a range between any two of them.

[0049] Furthermore, the burning temperature is 780-820°C, including but not limited to any point value of 780°C, 785°C, 790°C, 795°C, 800°C, 805°C, 810°C, 815°C or 820°C or a range value between any two of them.

[0050] Furthermore, the burning time is 0.5 to 1.5 h, including but not limited to any one of 0.5 h, 0.7 h, 0.9 h, 1.1 h, 1.3 h or 1.5 h or a range between any two of them.

[0051] The present invention improves the burning temperature and time, avoids the long-term high-temperature operation of the muffle furnace, reduces safety risks, and reduces the workload of personnel.

[0052] Furthermore, the amount of sulfuric acid solution added is 8 to 12 mL, including but not limited to any one of 8 mL, 9 mL, 10 mL, 11 mL or 12 mL or any range between two of them. 8 to 12 mL of sulfuric acid solution can fully dissolve the TiO in the sample to be tested. 2 .

[0053] Further, the concentration of the sulfuric acid solution is 7-8 moL / L, including but not limited to any one of 7 moL / L, 7.2 moL / L, 7.4 moL / L, 7.6 moL / L, 7.8 moL / L or 8 moL / L or a range between any two of them. 2 It can be dissolved in hot sulfuric acid solution with a concentration of 7 to 8 mol / L to form titanyl sulfate.

[0054] Furthermore, the temperature of the heating treatment is 290-310° C., including but not limited to any point value of 290° C., 295° C., 300° C., 305° C. or 310° C. or a range value between any two of them. Heating treatment within this temperature range can fully dissolve the titanium dioxide in the sample to be tested in the sulfuric acid solution, thereby improving the accuracy of the test result.

[0055] Furthermore, the heating treatment time is 2 to 4 hours, including but not limited to any one of 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours or a range between any two of them.

[0056] In some specific embodiments, the heating treatment comprises:

[0057] The mixture containing the first mixing system and the sulfuric acid solution is subjected to a first heat treatment at 195-205°C (for example, it may be but not limited to any point value of 195°C, 197°C, 199°C, 201°C, 203°C or 205°C, or a range value between any two of them); after the temperature of the mixture reaches 190-200°C (for example, it may be but not limited to any point value of 190°C, 192°C, 194°C, 196°C, 198°C or 200°C, or a range value between any two of them), a second heat treatment is performed at 290-310°C.

[0058] Furthermore, the heating rate of the second heating treatment is 8-12°C per 10 minutes, including but not limited to any point value of 8°C, 9°C, 10°C, 11°C or 12°C or a range value between any two of them. The heating rate of the second heating treatment is limited to a certain range to prevent local overheating, container rupture, sample overflow and splashing, which may cause detection errors and damage to test personnel.

[0059] During the heating treatment, the preheated sulfuric acid solution can be supplemented in an appropriate amount to ensure that there is a sufficient amount of sulfuric acid solution for dissolving the titanium dioxide.

[0060] Furthermore, every 100 mL of the second mixture contains 18 to 22 mL (for example, but not limited to, any one of 18 mL, 19 mL, 20 mL, 21 mL or 22 mL or a range between any two) of hydrogen peroxide. Adding a certain amount of hydrogen peroxide can fully react with the titanium sulfate generated in the second mixed system to generate a stable orange-yellow [TiO(H 2 O 2 )] 2+ .

[0061] Furthermore, the concentration of the hydrogen peroxide is 28 vol% to 32 vol%, including but not limited to any one of 28 vol%, 29 vol%, 30 vol%, 31 vol% or 32 vol% or a range between any two of them.

[0062] Furthermore, the absorbance value of the test liquid at a wavelength of 410 nm is detected.

[0063] Furthermore, the calculation formula of the titanium dioxide content in the sample to be tested is as follows:

[0064]

[0065] Where a is the TiO 2 b is the titanium content in the sample solution obtained from the standard curve, in mg / mL; m is the mass of the sample to be tested, in g.

[0066] Another aspect of the present invention also relates to a method for detecting the digestion and metabolism level of feed, including the method for detecting the titanium dioxide content in a sample.

[0067] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0068] Example 1

[0069] 1. Scope

[0070] Applicable to TiO in chyme, feed or feces 2 Determination of.

[0071] 2. Normative references

[0072] The clauses in the following documents become the clauses of this standard through reference in this standard. For all the referenced documents with dates, all the subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all the referenced documents without dates, the latest versions are applicable to this standard.

[0073] GB / T 6682-Specifications and test methods for water used in analytical laboratories.

[0074] 3. Determination principle

[0075] TiO 2It dissolves in hot concentrated sulfuric acid to form titanyl sulfate. Titanyl sulfate reacts with H 2 O 2 It can generate a relatively stable orange-yellow [TiO(H 2 O 2 )] 2+ Within a certain concentration range, its absorbance at a wavelength of 410 nm is similar to that of TiO 2 The content is linear.

[0076] TiO 2 +H 2 SO 4 =TiOSO 4 +H 2 O.

[0077] TiO 2 ++H 2 O 2 =[TiO(H 2 O 2 )] 2+ (orange).

[0078] 4. Materials and reagents

[0079] Sulfuric acid: high purity;

[0080] 30% hydrogen peroxide solution: analytical grade;

[0081] Titanium dioxide: analytical grade;

[0082] Titanium standard solution (0.5mg / mL): Accurately weigh 250mg (accurate to 0.0001g) of titanium dioxide on weighing paper, take a 500mL beaker and add 100mL of concentrated sulfuric acid, place it in an electric ceramic furnace and heat it at 300℃ until it is close to boiling. Slowly add titanium dioxide to the hot sulfuric acid while stirring, and heat at a constant temperature of 300℃ until the reaction is complete and the solid disappears. Transfer the contents of the beaker to a 500mL volumetric flask and rinse the beaker with a little distilled water. Slowly add 100mL of concentrated sulfuric acid to the volumetric flask and distilled water to 500mL;

[0083] 7.4 mol / L sulfuric acid solution: Slowly inject 400 mL of concentrated sulfuric acid into a 1000 mL beaker containing about 400 mL of distilled water and stir continuously with a glass rod. After the solution cools, transfer it to a 1000 mL volumetric flask and make up to volume with distilled water.

[0084] 5. Instruments and equipment

[0085] Spectrophotometer, analytical balance, electric hot plate, electric ceramic furnace, muffle furnace, volumetric flask, graduated pipette, beaker, reagent bottle, etc.

[0086] 6. Standard curve drawing

[0087] Use a graduated pipette to take 0mL, 1mL, 2mL, 3mL, 4mL, 5mL, 6mL, 7mL, 8mL, 9mL and 10mL of a titanium standard solution with a concentration of 0.5mg / mL, and inject them into 11 100mL volumetric flasks respectively. In the above volumetric flasks, add 10mL, 9mL, 8mL, 7mL, 6mL, 5mL, 4mL, 3mL, 2mL, 1mL and 0mL of a 7.4mol / L sulfuric acid solution in turn, shake well, add 20mL of hydrogen peroxide solution (30%) to each with a pipette, and finally make up to 100mL with distilled water. Use a sample that does not contain titanium as a blank to zero. On a spectrophotometer, use 410nm as the working wavelength to measure the absorbance of the solution in each volumetric flask. The maximum titanium concentration that is linearly related to the absorbance is 0.05mg / mL. Draw a standard curve based on the measured absorbance and titanium concentration, and the standard curve is as shown below. Figure 1 shown.

[0088] Depend on Figure 1 It can be seen that the standard curve equation of titanium concentration and absorbance value is y=0.1078x-9E-05, R 2 =0.9999. Correlation coefficient R 2 It is equal to 0.9999, indicating that the test data has a good fit with the standard curve equation and there is a strong linear correlation between titanium concentration and absorbance value.

[0089] 7. Test steps

[0090] (1) Weigh about 0.25 g of freeze-dried chyme sample or 0.75 g of feed sample (in parallel) into a porcelain crucible, carefully carbonize on an electric ceramic furnace until smokeless, the carbonization temperature is 200° C., the carbonization time is 1 h, and then burn in a muffle furnace at 800° C. for 1 h to obtain a first mixed system;

[0091] (2) After the first mixed system is cooled, the crucible residue is transferred to a 50 mL beaker, 10 mL of 7.4 mol / L sulfuric acid solution is added and the crucible is rinsed;

[0092] (3) Place the beaker on a hot plate, cover it with a concave glass sheet, and heat it at 200°C. When the contents of the beaker are close to the temperature, slowly increase the temperature of the hot plate. Do not let the solution boil, otherwise white β-hydrated titanium dioxide that is insoluble in acid and alkali will be produced, causing the experiment to fail. According to experience, it is best to increase the temperature by 10°C every 10 minutes and maintain it at 300°C. During the heating process, preheat 7.4 mol / L sulfuric acid solution at 200°C and replenish it in time. Heat for 3 hours until it is completely dissolved to obtain a second mixed system.

[0093] (4) After the second mixed system is cooled, rinse the contents of the beaker with 25 mL of distilled water and transfer to a 100 mL volumetric flask; add 20 mL of H 2 O2 (30%), distilled water to 100 mL; filter with qualitative filter paper, and compare the filtrate at 410 nm.

[0094] 8. Calculation formula

[0095]

[0096] a-TiO in the sample 2 content(%);

[0097] b-Check the titanium concentration (mg / mL) in the sample solution on the standard curve;

[0098] m-sample mass (g).

[0099] 9. Improve the results of sample weighing test

[0100] As shown in Table 1, the sample weight of chyme is 0.25 g, and its absorbance value of 0.339 is in the median of the standard absorbance value (0-0.5), with a small relative error, which can improve the accuracy and reliability of the detection.

[0101] Table 1 Freeze-dried chyme samples

[0102]

[0103] As shown in Table 2, the feed sample weight is 0.75g, and the TiO 2 The content was 0.4018%, which is closest to the TiO2 in feed. 2 Content 0.4002%.

[0104] Table 2 Feed samples

[0105]

[0106] 10. Precision test results

[0107] Add 0.4% TiO to the diet at 18 and 39 days of age 2 Mix well, feed continuously for 3 days before slaughter, collect ileum chyme for determination. Fast for 2 hours the night before collecting chyme, start feeding 3 hours before sampling to ensure that there is enough chyme in the ileum. After the chyme is fully mixed, place it in a clean covered culture dish, dry it in a 65℃ oven, pulverize it after rehumidification in the air for 24 hours, pass it through a 40-mesh sieve, and detect the content of titanium dioxide. The results are shown in Tables 3 and 4.

[0108] Table 3 Average measured values ​​of titanium dioxide in feed samples (n=10)

[0109]

[0110] Table 4 Average determination values ​​of titanium dioxide in ileal chyme samples (n=10)

[0111]

[0112] According to the test method, the feed and ileum digesta samples of broiler metabolism test were measured 10 times in parallel. The average value of titanium dioxide in feed samples was 0.4042%, and the relative standard deviation (n=10) of the measured value was 2.68%; the average value of titanium dioxide in ileum digesta samples was 10.5966g / kg, and the relative standard deviation (n=10) of the measured value was 4.96%. The relative standard deviation values ​​of the two samples were within 5%, indicating that the precision of this method met the detection requirements and the test results obtained were accurate and reliable.

[0113] 11. Recovery test results

[0114] Add 0.4% TiO to the diet 2 Mix well and detect the titanium dioxide content in the sample according to the test method. The recovery rate is calculated as follows:

[0115] Recovery rate = (actual detected amount / amount added in feed) × 100%.

[0116] As shown in Table 5, the recovery rates of titanium dioxide in feed under the muffle furnace treatment conditions of 580°C, 13h and 800°C, 1h are 111.66% and 100.14% respectively, indicating that the muffle furnace calcination conditions of the present invention are 800°C, 1h, and the recovery rate of titanium dioxide detected is closer to 100%, and the standard deviation is relatively small. The required instruments and equipment of this method can be met by most laboratories, the sample pretreatment is simple and fast, the test result recovery rate is high, the repeatability is good, and the risk of using the muffle furnace at high temperature overnight and the workload of the experimenter are reduced, and it can be used for the inspection of samples in metabolic tests.

[0117] Table 5 Recovery of titanium dioxide in feed

[0118]

[0119] Example 2

[0120] The method for detecting the content of titanium dioxide in a sample provided in this embodiment, the method for drawing a standard curve is the same as that in Example 1, comprising the following steps:

[0121] (1) Weigh about 0.7 g of feed sample (do parallel) into a porcelain crucible, carefully carbonize it on an electric ceramic furnace until smokeless, the carbonization temperature is 100° C., the carbonization time is 1.5 h, and then burn it in a muffle furnace at 820° C. for 0.5 h to obtain a first mixed system;

[0122] (2) After the first mixed system is cooled, the crucible residue is transferred to a 50 mL beaker, 8 mL of 8 mol / L sulfuric acid solution is added and the crucible is rinsed;

[0123] (3) Place the beaker on a hot plate, cover it with a concave glass sheet, and heat it at 200°C. When the contents of the beaker are close to the temperature, slowly increase the temperature of the hot plate. Do not let the solution boil, otherwise white β-hydrated titanium dioxide that is insoluble in acid and alkali will be produced, causing the experiment to fail. According to experience, it is best to increase the temperature by 10°C every 10 minutes and maintain it at 290°C. During the heating process, preheat 8 mol / L sulfuric acid solution at 200°C and replenish it in time. Heat for 2 hours until it is completely dissolved to obtain a second mixed system.

[0124] (4) After the second mixed system is cooled, rinse the contents of the beaker with 25 mL of distilled water and transfer to a 100 mL volumetric flask; add 18 mL of H 2 O 2 (32 vol%), distilled water was used to make the volume to 100 mL; the solution was filtered with qualitative filter paper, and the filtrate was colorimetrically analyzed at 410 nm.

[0125] Example 3

[0126] The method for detecting the content of titanium dioxide in a sample provided in this embodiment, the method for drawing a standard curve is the same as that in Example 1, comprising the following steps:

[0127] (1) Weigh about 0.8 g of feed sample (do parallel) into a porcelain crucible, carefully carbonize it on an electric ceramic furnace until smokeless, the carbonization temperature is 300° C., the carbonization time is 0.5 h, and then burn it in a muffle furnace at 780° C. for 1.5 h to obtain a first mixed system;

[0128] (2) After the first mixed system is cooled, the crucible residue is transferred to a 50 mL beaker, 12 mL of 7 mol / L sulfuric acid solution is added and the crucible is rinsed;

[0129] (3) Place the beaker on a hot plate, cover it with a concave glass sheet, and heat it at 200°C. When the contents of the beaker are close to the temperature, slowly increase the temperature of the hot plate. Do not let the solution boil, otherwise white β-hydrated titanium dioxide that is insoluble in acid and alkali will be produced, causing the experiment to fail. According to experience, it is best to increase the temperature by 10°C every 10 minutes and maintain it at 310°C. During the heating process, preheat the 7 mol / L sulfuric acid solution at 200°C and replenish it in time. Heat for 4 hours until it is completely dissolved to obtain the second mixed system.

[0130] (4) After the second mixed system is cooled, rinse the contents of the beaker with 25 mL of distilled water and transfer to a 100 mL volumetric flask; add 22 mL of H 2 O 2 (28 vol%), distilled water was used to make the volume to 100 mL; the solution was filtered with qualitative filter paper, and the filtrate was colorimetrically analyzed at 410 nm.

[0131] Comparative Example 1

[0132] The only difference between this comparative example and Example 1 is that the burning temperature in the test step (1) is 750°C.

[0133] Comparative Example 2

[0134] The only difference between this comparative example and Example 1 is that the concentration of the sulfuric acid solution used in the test step is 6.5 mol / L.

[0135] Comparative Example 3

[0136] The difference between this comparative example and Example 1 is that in step (4), 15 mL of H 2 O 2 (30%).

[0137] Table 6

[0138]

[0139] It can be seen from Table 6 that the burning temperature, sulfuric acid solution concentration and H 2 O 2 The concentration of TiO 2 This affects the accuracy of the test results and the recovery rate of titanium dioxide.

[0140] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for detecting the content of titanium dioxide in a sample, characterized in that: The following steps are involved: (a) carbonizing and burning the sample to be tested to obtain a first mixed system; (b) heating the first mixture containing the first mixed system and the sulfuric acid solution to obtain a second mixed system; (c) filtering the second mixture containing the second mixed system, water and hydrogen peroxide to obtain a test solution; (d) detecting the absorbance value of the test liquid, and calculating the titanium dioxide content in the test sample according to the absorbance value.

2. The method for detecting titanium dioxide content in a sample according to claim 1, characterized in that: The sample to be tested includes at least one of chyme, feed or feces.

3. The method for detecting titanium dioxide content in a sample according to claim 2, characterized in that: Includes at least one of the following technical features: (1) When the sample to be tested is chyme, weigh 0.2-0.3 g of chyme for carbonization; (2) When the sample to be tested is feed, weigh 0.7-0.8 g of feed for carbonization; (3) When the sample to be tested is feces, 0.1 to 0.4 g of feces is weighed and carbonized.

4. The method for detecting titanium dioxide content in a sample according to claim 1, characterized in that: The carbonization temperature is 100-300°C; And / or, the carbonization time is 0.5 to 1.5 hours.

5. The method for detecting titanium dioxide content in a sample according to claim 1, characterized in that: The burning temperature is 780-820°C; And / or, the burning time is 0.5 to 1.5 hours.

6. The method for detecting titanium dioxide content in a sample according to claim 1, characterized in that: Includes at least one of the following technical features: (1) The amount of sulfuric acid solution added is 8 to 12 mL; (2) The concentration of the sulfuric acid solution is 7 to 8 mol / L; (3) each 100 mL of the second mixture contains 18 to 22 mL of hydrogen peroxide; (4) The concentration of the hydrogen peroxide is 28 vol% to 32 vol%.

7. The method for detecting titanium dioxide content in a sample according to claim 1, characterized in that: The temperature of the heating treatment is 290-310°C; And / or, the heating treatment time is 2 to 4 hours.

8. The method for detecting titanium dioxide content in a sample according to claim 1, characterized in that: Detect the absorbance of the test solution at a wavelength of 410 nm.

9. The method for detecting titanium dioxide content in a sample according to claim 1, characterized in that: The calculation formula of the titanium dioxide content in the sample to be tested is as follows: Wherein, a is the TiO2 content in the sample to be tested, in %; b is the titanium concentration in the sample solution found on the standard curve, in mg / mL; m is the mass of the sample to be tested, in g.

10. A method for detecting the level of feed digestion and metabolism, characterized in that: A method for detecting titanium dioxide content in a sample comprising the method described in any one of claims 1 to 9.

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