A detection structure capable of quickly identifying ferroferric oxide, a preparation method and application thereof

Abstract

The application discloses a detection structure capable of quickly identifying ferroferric oxide, and a preparation method and application thereof. The detection structure comprises a base body, and potassium ferricyanide and ammonium thiocyanate which are respectively adsorbed on opposite ends of the base body. The detection structure can quickly identify whether the ferroferric oxide is contained in a to-be-detected substance. The detection structure has low detection limit, high accuracy and simple operation.

Description

Technical Field

[0001] This invention relates to the field of magnetite detection. More specifically, it relates to a detection structure for rapidly identifying magnetite, its preparation method, and its applications. Background Technology

[0002] Iron, the fourth most abundant element on Earth, is widely distributed in the Earth's crust. Iron ions are essential for the human body, forming the core of hemoglobin and playing an irreplaceable role in metabolic activities. However, excessive iron ion levels can damage organs such as the liver. Therefore, the iron ion concentration in the body should not be too high or too low. Iron ion detection methods typically include atomic absorption spectrophotometry, inductively coupled plasma atomic emission spectrometry, and fluorescence spectroscopy. These methods often require expensive equipment and are relatively complex to operate. Among these, techniques utilizing fluorescent or colorimetric probes for iron ion detection include methods and kits for detecting ferrous ions (Fe2O3) and the use of rhodamine as a fluorescent probe for detecting ferric ions (Fe3O4). Iron(III) oxide (Fe3O4) is a magnetic black crystal, also known as magnetic iron oxide. It is insoluble in water, alkalis, and organic solvents such as ethanol, but naturally occurring iron(III) oxide is insoluble in acids. In humid conditions, it easily oxidizes to ferric oxide (Fe2O3) in air. Iron(III) oxide is commonly used as a pigment and polishing agent, and also in the manufacture of audio tapes and telecommunications equipment. Current research has focused on the properties of iron(III) oxide and its interactions with other chemical substances. Developing new, rapid, and accurate methods for detecting iron(III) oxide has been a key focus for researchers in this field. Summary of the Invention

[0003] To address the above problems, the present invention aims to provide a detection structure for rapidly identifying iron(III) oxide, its preparation method, and its applications. This detection structure can rapidly identify whether a analyte contains iron(III) oxide. Furthermore, this detection structure has a low detection limit for iron(III) oxide, high accuracy, and is simple to operate.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] On the one hand, the present invention provides a detection structure for rapidly identifying iron(III) oxide, the detection structure comprising a matrix and potassium ferricyanide and ammonium thiocyanate respectively adsorbed on opposite ends of the matrix.

[0006] Furthermore, the substrate is selected from cotton swabs or filter paper.

[0007] Furthermore, both ends of the cotton swab are provided with cotton loops.

[0008] Furthermore, when the substrate is a cotton swab, the adsorption capacity of potassium ferricyanide and ammonium thiocyanate on the substrate is independently 0.1–1000 μg / cm³. 2 .

[0009] Furthermore, when the substrate is filter paper, the adsorption capacity of potassium ferricyanide and ammonium thiocyanate on the substrate does not exceed 5 ± 0.5 μg / cm³. 2 .

[0010] Although iron(III) oxide can be written with the chemical formula Fe3O4, it is actually a mixture composed of ferric oxide (Fe2O3) and ferrous oxide (FeO). The double displacement reaction between iron(III) oxide and acids is actually two separate reactions. Taking the reaction with hydrochloric acid as an example, when iron(III) oxide reacts with acid, it produces ferrous chloride, ferric chloride, and water. The reaction equation is shown below:

[0011] Fe₂O₃ + 6HCl = 2FeCl₃ + 3H₂O

[0012] FeO + 2HCl = FeCl₂ + H₂O

[0013] It is worth noting that different acids react differently with iron(III) oxide. Weak acids generally do not react with iron(III) oxide, with very few exceptions (such as H₂S); strong acids without oxidizing anions (such as HCl) produce one times the amount of Fe²⁺ and two times the amount of Fe³⁺ after reaction; strong acids with oxidizing anions (such as HNO₃) produce all Fe³⁺ after reaction; and HI produces all Fe²⁺ after reaction. This indicates that iron(III) oxide can be identified by the valence state of the iron ions in the products generated from its reaction with different acids. Therefore, the main mechanism for identifying iron(III) oxide is based on the formation of ferrous (Fe²⁺) and ferric (Fe³⁺) ions under acidic conditions.

[0014] Upon reaction with dilute hydrochloric acid, it produces ferrous ions (Fe2O3). When potassium ferricyanide aqueous solution is added, a reaction occurs to form a deep blue precipitate, Prussian blue. The solution color changes from its original light green or yellow to deep blue, which is an important indicator of the presence of iron(III) oxide. The reaction equation is as follows:

[0015] 3Fe2++2[Fe(CN)6]3-═Fe3[Fe(CN)6]2

[0016] According to the above reaction equation, the dark blue precipitate indicates the presence of ferrous ions in the solution; if no dark blue precipitate appears in the solution, it indicates that the solution may not contain ferrous ions or the content of ferrous ions is extremely low and could not be detected under experimental conditions.

[0017] Ammonium thiocyanate was selected as the identification reagent for ferric ions. When ammonium thiocyanate solution was added to a solution containing ferric ions, the solution quickly turned blood red. This obvious phenomenon provides a simple method for the detection of ferric ions. The principle is that ammonium thiocyanate reacts with ferric ions to form blood-red ferric thiocyanate, and the reaction equation is as follows:

[0018] Fe3++3SCN-=Fe(SCN)3

[0019] According to the above reaction equation, the solution turning blood red indicates the presence of iron ions; if the solution does not turn blood red, it means that the solution does not contain iron ions or the content of iron ions is so low that it could not be detected under experimental conditions.

[0020] In another aspect, the present invention provides a method for preparing the detection structure as described above, the method comprising the following steps:

[0021] One end of the substrate was immersed in an aqueous solution of potassium ferricyanide, and the other end of the substrate was immersed in an aqueous solution of ammonium thiocyanate. After immersion, the substrate was dried to obtain the detection structure.

[0022] Furthermore, the concentration of the aqueous solution of potassium ferricyanide is 0.8-1.5 mmol / L. -1 Preferably 1 mmol L -1 .

[0023] Furthermore, the concentration of the aqueous solution of ammonium thiocyanate is 0.8-1.5 mmol / L. -1 Preferably 1 mmol L -1 .

[0024] Furthermore, each soaking time is 1-30 minutes.

[0025] Furthermore, the drying temperature is 80-90°C, preferably, and the drying time is 0.5-10 hours.

[0026] On another front, the present invention provides the application of the detection structure described above in the rapid identification of iron(III) oxide.

[0027] Furthermore, the application includes the following steps:

[0028] Add concentrated hydrochloric acid dropwise to the substance to be tested, let stand, and obtain the test solution;

[0029] The test solution is dropped onto the end of the matrix in the detection structure where potassium ferricyanide is adsorbed and the end where ammonium thiocyanate is adsorbed, respectively. The color change of the detection structure is used to determine whether the test substance contains iron(III) oxide.

[0030] After standing, the supernatant is taken as the solution to be tested.

[0031] Further, the concentration of the concentrated hydrochloric acid relative to the substance to be tested is (4-8) mL / g, preferably 5 mL / g. Further, the method for determining whether the substance to be tested contains iron(III) oxide is as follows:

[0032] If, in the detection structure, the color of the end with adsorbed ammonium thiocyanate changes from light green or yellow to blood red, and

[0033] In the detection structure, the color of the end where potassium ferricyanide is adsorbed changes from light green or yellow to dark blue.

[0034] Then it is determined that the substance to be tested contains iron(III) oxide;

[0035] Otherwise, the substance to be tested does not contain iron(III) oxide.

[0036] The beneficial effects of this invention are as follows:

[0037] The detection structure provided in this invention uses both potassium ferricyanide and ammonium thiocyanate as substances for identifying and determining iron(III) oxide. By controlling the adsorption amount of both on the substrate, the detection structure achieves rapid, accurate, and extremely low detection limits when detecting iron(III) oxide, overcoming the problem that no rapid identification product for iron(III) oxide has been developed on the market. Detailed Implementation

[0038] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1:

[0040] The preparation steps of a rapid identification cotton swab based on iron oxide are as follows:

[0041] 1) Preparation of potassium ferricyanide solution: Dissolve potassium ferricyanide crystals in distilled water to prepare a solution with a concentration of 1 mmol / L. -1 A solution; for example, 2 mg of potassium ferricyanide can be weighed and dissolved in distilled water to prepare a solution with a concentration of 1 mmol / L. -1 A potassium ferricyanide solution showed a yellow-green fluorescence.

[0042] Preparation of ammonium thiocyanate solution: Dissolve ammonium thiocyanate in distilled water to prepare a solution with a concentration of 1 mmol / L. -1 A solution; for example, 2 mg of ammonium thiocyanate can be weighed and dissolved in distilled water to prepare a solution with a concentration of 1 mmol / L. -1 Ammonium thiocyanate solution;

[0043] 2) Preparation of test cotton swabs: Soak one end of a cotton swab (with cotton loops at both ends) in the above potassium ferricyanide solution, take it out after 5 minutes, and place it in an oven at 80°C to dry for 1 hour to obtain a cotton swab with potassium ferricyanide adsorbed at one end.

[0044] The cotton loop at the other end of the cotton swab is immersed in the above ammonium thiocyanate solution. After 5 minutes, it is taken out and placed in an oven at 80°C to dry for 1 hour, resulting in a cotton swab with potassium ferricyanide adsorbed at one end and ammonium thiocyanate adsorbed at the other end.

[0045] The method for rapid detection of iron(III) oxide using this cotton swab includes the following steps:

[0046] 3) Take 1g of the sample to be tested and place it in a test tube. Add 5mL of concentrated hydrochloric acid to the test tube, mix well, and let stand.

[0047] 4) After the reaction is complete, take the supernatant and drop it onto the two ends of the cotton swabs prepared in step 2), which are respectively adsorbed with potassium ferricyanide and ammonium thiocyanate (make sure it is dropped onto potassium ferricyanide and ammonium thiocyanate respectively), and observe the color change.

[0048] 5) It can be seen that the potassium ferricyanide end of the cotton swab turns dark blue, and the ammonium thiocyanate end turns blood red. Therefore, it is determined that iron(III) oxide is present in the sample to be tested.

[0049] In the above method, the color development time of the test strip is within 10 seconds, and the detection limit for the concentration of ferric oxide in the sample is 10. -5 mol L -1 the following.

[0050] The presence of iron(III) oxide in the sample was confirmed by absorption spectroscopy.

[0051] Example 2

[0052] The preparation steps of a rapid identification test strip based on iron(III) oxide are as follows:

[0053] 1) Preparation of potassium ferricyanide solution: Weigh potassium ferricyanide crystals, dissolve them in distilled water, and prepare a solution with a concentration of 1 mmol / L. -1 For example, weigh 2 mg of potassium ferricyanide, dissolve it in distilled water, and prepare a solution with a concentration of 1 mmol / L. -1 A potassium ferricyanide solution showed a yellow-green fluorescence.

[0054] Preparation of ammonium thiocyanate solution: Dissolve ammonium thiocyanate in distilled water to prepare a solution with a concentration of 1 mmol / L. -1 For example, weigh 2 mg of ammonium thiocyanate, dissolve it in distilled water, and prepare a solution with a concentration of 1 mmol / L. -1Ammonium thiocyanate solution;

[0055] 2) Preparation of test paper: Immerse one end of filter paper in the above potassium ferricyanide solution, take it out after 5 minutes, and dry it in an oven at 80°C for 1 hour to obtain potassium ferricyanide test paper.

[0056] The other end of the potassium ferricyanide test paper (the end not soaked in potassium ferricyanide solution) is immersed in the above ammonium thiocyanate solution. After 5 minutes, it is taken out and placed in an oven at 80°C to dry for 1 hour to obtain potassium ferricyanide ammonium thiocyanate test paper.

[0057] The method for rapid detection of iron(III) oxide using this test strip includes the following steps:

[0058] Take 1g of the sample to be tested and place it in a test tube. Add 5mL of 0.1mol / L solution to the test tube. -1 Mix the dilute hydrochloric acid solution, let it stand;

[0059] 4) After the reaction is complete, take the supernatant and drop it onto the potassium ferricyanide end and ammonium thiocyanate end of the test paper prepared in step 2), respectively, and observe the color change.

[0060] 5) It can be seen that no color change occurred at the potassium ferricyanide end and the ammonium thiocyanate end of the test paper; therefore, the sample to be tested does not contain iron(III) oxide.

[0061] Absorption spectroscopy was used to test the sample, confirming that there was no iron(III) oxide in the sample.

[0062] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A detection structure for rapid identification of iron(III) oxide, characterized in that, The detection structure includes a matrix, and potassium ferricyanide and ammonium thiocyanate adsorbed on opposite ends of the matrix, respectively.

2. The detection structure according to claim 1, characterized in that, The substrate is selected from cotton swabs or filter paper.

3. The detection structure according to claim 2, characterized in that, When the substrate is a cotton swab, the adsorption capacity of potassium ferricyanide and ammonium thiocyanate on the substrate is independently 0.1–1000 μg / cm³. 2 ;or When the substrate is filter paper, the adsorption capacity of potassium ferricyanide and ammonium thiocyanate on the substrate does not exceed 5 ± 0.5 μg / cm³. 2 .

4. The method for preparing the detection structure according to any one of claims 1-3, characterized in that, Includes the following steps: One end of the substrate was immersed in an aqueous solution of potassium ferricyanide, and the other end of the substrate was immersed in an aqueous solution of ammonium thiocyanate. After immersion, the substrate was dried to obtain the detection structure.

5. The preparation method according to claim 4, characterized in that, The concentrations of the aqueous solutions of ammonium thiocyanate and potassium ferricyanate are each independently 0.8-1.5 mmol / L. -1 Preferably 1 mmol L -1 .

6. The preparation method according to claim 4, characterized in that, Each soaking time is 1-30 minutes; and / or The drying temperature is 80-90℃, preferably 80℃, and the drying time is 0.5-10 hours.

7. The application of the detection structure as described in any one of claims 1-3 in the rapid identification of iron(III) oxide.

8. The application according to claim 7, characterized in that, The application includes the following steps: Add concentrated hydrochloric acid dropwise to the substance to be tested, let stand, and obtain the test solution; The test solution is dropped onto the end of the matrix in the detection structure where potassium ferricyanide is adsorbed and the end where ammonium thiocyanate is adsorbed, respectively. The color change of the detection structure is used to determine whether the test substance contains iron(III) oxide.

9. The application according to claim 8, characterized in that, The concentration of the concentrated hydrochloric acid relative to the substance to be detected is (4-8) mL / g, preferably 5 mL / g.

10. The application according to claim 8, characterized in that, The method for determining whether the substance to be tested contains iron(III) oxide is as follows: If, in the detection structure, the color of the end with adsorbed ammonium thiocyanate changes from light green or yellow to blood red, and In the detection structure, the color of the end where potassium ferricyanide is adsorbed changes from light green or yellow to dark blue. Then it is determined that the substance to be tested contains iron(III) oxide; Otherwise, the substance to be tested does not contain iron(III) oxide.