Iron ion detection fluorescent probe, application and fluorescent detection method

Abstract

The present application relates to a kind of iron ion detection fluorescent probe, application and fluorescence detection method, belong to iron content detection technical field, solve the technical problems such as the operation of the iron content detection in magnesium oxide is complicated, time-consuming etc..The preparation steps of fluorescent probe are as follows: step one, pyrazine-2,3,5,6-tetramethylic acid and Zn(NO) 3 are weighed and dissolved in the mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide, after stirring, mixed solution is obtained;Step two, the mixed solution obtained in step one is placed in oven and continuously heated, white transparent block crystal is obtained, after washing, filtering, drying and grinding, the fluorescent probe is obtained.The present application synthesizes a new type of zinc-based compound by solvothermal method, as fluorescent probe is used for the fluorescence detection of iron ion in magnesium oxide, can realize the trace detection of iron ion to screen out low magnetic magnesium oxide with iron content meeting industry standard requirements.

Description

Technical Field

[0001] This invention belongs to the field of iron content detection technology, specifically relating to a fluorescent probe for iron ion detection, its application, and a fluorescence detection method. Background Technology

[0002] Magnesium oxide, also known as magnesia, is a white, hygroscopic solid mineral that exists in nature in the form of periclase and is a raw material for smelting magnesium (or oxides). As a refractory material, magnesium oxide possesses physical and chemical stability at high temperatures; as a building material, it exhibits excellent properties such as fire resistance, termite resistance, moisture resistance, mildew resistance, and high strength; as an antacid, magnesium supplement, and short-term laxative, it can also be used in the medical field to relieve heartburn and indigestion. With increasing purity, the application performance of magnesium oxide improves; therefore, it is necessary to monitor the impurity content in high-purity magnesium oxide.

[0003] The impurity content of high-purity magnesium oxide needs to be strictly controlled. Depending on customer requirements, calcium, iron, silicon, aluminum, and heavy metals must all meet specific standards to ensure product quality and performance. Iron, a common impurity in magnesium oxide, has specific content requirements in industry standards. For example, HG / T-6066-2022 stipulates that the iron ion content in magnesium oxide for mineral-insulated cables should be less than or equal to 0.5%.

[0004] The common method for detecting iron ions usually follows GB / T5069-2015 Chemical Analysis Methods for Magnesium-Aluminum Refractory Materials: o-Phenanthroline Spectrophotometric Method. The principle involves melting the ferrous ions with a sodium carbonate-boric acid flux and leaching them with dilute hydrochloric acid. Hydroxylamine hydrochloride reduces Fe(III) to Fe(II). In a weakly acidic solution, Fe(II) forms an orange-red complex with o-Phenanthroline, and its absorbance is measured at a spectrophotometer wavelength of 510 nm. This method is accurate, but it also has some disadvantages that hinder enterprise applications, such as complex operation, long processing time, and the need for numerous reagents.

[0005] Therefore, it is urgent to develop a rapid method for detecting iron impurities that meets the industry standards for magnesium oxide. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fluorescent probe for iron ion detection, its application, and a fluorescence detection method, which solves the technical problems of cumbersome operation and time consumption in the detection of iron content in magnesium oxide.

[0007] To address the aforementioned problems, the technical solution of this invention is: a fluorescent probe for iron ion detection, wherein the molecular formula of the fluorescent probe is (Zn2(C8O8N2H2)·DMSO·HCOOH). n .

[0008] Preferably, the preparation steps of the fluorescent probe are as follows:

[0009] Step 1: Weigh pyrazine-2,3,5,6-tetracarboxylic acid and Zn(NO)3 and dissolve them in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). After stirring, a mixed solution is obtained. The mass ratio of pyrazine-2,3,5,6-tetracarboxylic acid to Zn(NO)3 is 1:6, and the volume ratio of N,N-dimethylformamide (DMF) to dimethyl sulfoxide (DMSO) is 3:1.

[0010] Step 2: Place the mixed solution obtained in Step 1 in an oven at 90℃±5℃ and heat continuously for 4-6 days to obtain white transparent block crystals. After washing, filtering, drying and grinding the white transparent block crystals, the fluorescent probe is obtained.

[0011] Preferably, the stirring time in step one is 30-60 minutes.

[0012] Another object of the present invention is to provide an application of the above-mentioned iron ion detection fluorescent probe in the rapid detection of iron content in magnesium oxide.

[0013] Another object of the present invention is to provide a rapid fluorescence detection method for detecting iron content in magnesium oxide, comprising the following steps:

[0014] Step 1: Weigh 0.5g of dried magnesium oxide into a platinum crucible. Add 4.0g of anhydrous sodium carbonate and 2.7g of boric acid to the platinum crucible and mix well. Cover with a platinum lid, leaving a slight gap, and place in a high-temperature furnace. First, heat slowly, then gradually increase the temperature to 1100℃±25℃ and heat for 10 minutes. Remove the crucible and cover it with a platinum lid or watch glass. After the crucible has cooled slightly, add 55mL of sulfuric acid solution while stirring. Heat in a steam bath until the sample is completely dissolved. After cooling, transfer to a volumetric flask and dilute to volume to obtain a magnesium oxide solution.

[0015] Step 2: Take 1 mg of the above-mentioned iron ion detection fluorescent probe, add 3 mL of the magnesium oxide solution prepared in Step 1, mix well, and measure the fluorescence intensity of the iron ion detection fluorescent probe at an excitation wavelength of 290 nm.

[0016] Preferably, in step two, the volume ratio of sulfuric acid to water in the sulfuric acid solution is 1:9.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The fluorescence detection method of this invention uses pyrazine-2,3,5,6-tetracarboxylic acid as a ligand to synthesize a novel zinc-based compound via a solvothermal method. This compound serves as a fluorescent probe for the fluorescence detection of iron ions in magnesium oxide, enabling trace detection of iron ions and thus screening for low-magnetic magnesium oxide with iron content meeting industry standards. The method of this invention for determining the iron content in industrial magnesium oxide features rapid response, high selectivity, high sensitivity, and low cost. Compared with existing iron ion detection technologies, this fluorescence detection technology offers advantages such as low cost, high sensitivity, and ease of operation, and has promising market application prospects. Attached Figure Description

[0019] Figure 1 The structure of the pyrazine-2,3,5,6-tetracarboxylic acid ligand is shown.

[0020] Figure 2 This is a diagram of the coordination environment of the fluorescent probe for iron ion detection.

[0021] Figure 3 This is a two-dimensional structural diagram of the fluorescent probe for iron ion detection;

[0022] Figure 4 The powder line diffraction pattern of the fluorescent probe for iron ion detection;

[0023] Figure 5 The infrared spectrum of the fluorescent probe for iron ion detection;

[0024] Figure 6 The image shows the detection of metal ions by the fluorescent probe for iron ion detection.

[0025] Figure 7 For different Fe 3+ Fluorescence changes at different concentrations;

[0026] Figure 8 The equation is the Stern-Volmer (SV) equation.

[0027] Figure 9 Bar chart showing the anti-interference experiments in different solutions. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0029] Example 1: This example provides a fluorescent probe for iron ion detection. The molecular formula of the fluorescent probe is (Zn2(C8O8N2H2)·DMSO·HCOOH). n .

[0030] The preparation steps of the fluorescent probe for iron ion detection are as follows:

[0031] Step 1: Weigh pyrazine-2,3,5,6-tetracarboxylic acid and Zn(NO)3 and dissolve them in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Stir for 30-60 minutes to obtain a mixed solution. The mass ratio of pyrazine-2,3,5,6-tetracarboxylic acid to Zn(NO)3 is 1:6, and the volume ratio of N,N-dimethylformamide (DMF) to dimethyl sulfoxide (DMSO) is 3:1.

[0032] Step 2: Place the mixed solution obtained in Step 1 in an oven at 90℃±5℃ and heat continuously for 4-6 days to obtain white transparent block crystals. After washing, filtering, drying and grinding, the white transparent block crystals are used to obtain the iron ion detection fluorescent probe.

[0033] Example 2: This example provides an application of the iron ion detection fluorescent probe from Example 1 in the rapid detection of iron content in magnesium oxide.

[0034] Example 3: This example provides a rapid fluorescence detection method for detecting iron content in magnesium oxide, including the following steps:

[0035] Step 1: Weigh 0.5g of dried magnesium oxide into a platinum crucible. Add 4.0g of anhydrous sodium carbonate and 2.7g of boric acid to the platinum crucible and mix well. Cover with a platinum lid, leaving a slight gap, and place in a high-temperature furnace. Heat slowly first, then gradually increase the temperature to 1100℃±25℃ and heat for 10 minutes. Remove the crucible and cover it with a platinum lid or watch glass. After the crucible has cooled slightly, add 55mL of sulfuric acid solution while stirring. The volume ratio of sulfuric acid to water in the sulfuric acid solution is 1:9. Heat in a steam bath until the sample is completely dissolved. After cooling, transfer to a volumetric flask and dilute to volume to obtain a magnesium oxide solution.

[0036] Step 2: Take 1 mg of the iron ion detection fluorescent probe from Example 1, add 3 mL of the magnesium oxide solution prepared in Step 1, mix well, and measure the fluorescence intensity of the iron ion detection fluorescent probe at an excitation wavelength of 290 nm. Determine whether the iron ion content in the magnesium oxide solution meets the industry standard based on whether the sample fluorescence decreases, thereby screening out magnesium oxide with iron content that meets the industry standard requirements.

[0037] I. Structure and characterization of the iron ion detection fluorescent probe of the present invention;

[0038] (1) Structural analysis: Figure 1 It represents the structure of a pyrazine-2,3,5,6-tetracarboxylic acid ligand. Figure 2 For the coordination environment of the prepared iron ion fluorescent probe, each Zn 2+ It is coordinated with four oxygen atoms and one nitrogen atom, wherein the coordinated oxygen atoms are carboxyl groups from three different ligands. Figure 3This is a two-dimensional structural diagram of the fluorescent probe for iron ion detection.

[0039] (2) Powder diffraction characterization: Figure 4 The powder line diffraction pattern of the prepared iron ion fluorescent probe is shown below. Figure 4 As shown, the characteristic diffraction peaks in the simulated PXRD correspond well with those in the actual synthesized PXRD, indicating that the prepared iron ion detection fluorescent probe is a pure phase.

[0040] (3) Infrared spectroscopy characterization of phase composition: The infrared spectra of the complex material were tested using an FT-IR spectrometer with a scanning range of 4000 cm⁻¹. -1 -400cm -1 . Figure 5 The infrared spectrum of the fluorescent probe for iron ion detection is shown at 1631 cm⁻¹. -1 A distinct characteristic peak appears at the wavelength, which is attributed to the completely deprotonated carboxyl group, consistent with the structural analysis of the single crystal results.

[0041] II. Calculation of the detection limit: The iron ion detection fluorescent probe prepared in Example 1 was shaken thoroughly with a series of metal ion solutions of known concentrations to obtain standard samples. The fluorescence of each standard sample was measured at an excitation wavelength of 290 nm. It was found that the probe has a fluorescence quenching effect on iron ions, such as... Figure 6 As shown.

[0042] III. Calculation of Detection Limit: The iron ion detection fluorescent probe prepared in Example 1 was shaken evenly with a series of iron ion solutions of known concentrations to obtain standard samples. The fluorescence of each standard sample was measured at an excitation wavelength of 290 nm. A linear relationship model was constructed with iron ion concentration as the abscissa and fluorescence intensity as the ordinate, and the detection limit was calculated. Figure 7 and Figure 8 As shown.

[0043] IV. Anti-interference detection: The iron ion detection fluorescent probe prepared in Example 1 was reacted with iron ions and a series of other metal ion solutions of known concentrations (Mg). 2+ Ca 2+ Al 3+ Standard samples were obtained by oscillating SiO2 to obtain homogeneous samples. The fluorescence of each standard sample was measured at an excitation wavelength of 290 nm. A bar chart model was constructed with the other added metal ions as the x-axis and the fluorescence intensity as the y-axis, as shown in the figure. Figure 9 As shown.

[0044] V. Actual Sample Testing: Take 1 mg of the iron ion detection fluorescent probe prepared in Example 1 and mix it evenly with 3 mL of the sample to be tested. Then, test the fluorescence of the mixture at an excitation wavelength of 290 nm. Determine whether the iron ion content in the sample meets the industry standard based on whether the sample fluorescence decreases. In this way, magnesium oxide with iron content that meets the industry standard requirements can be screened out.

[0045] Example 3: This example provides a rapid fluorescence detection method for detecting iron content in magnesium oxide, including the following steps:

[0046] Step 1: Accurately weigh 5 mg of pyrazine-2,3,5,6-tetracarboxylic acid and 30 mg of Zn(NO)3, dissolve them in a mixed solvent of 2.25 mL of N,N-dimethylformamide (DMF) and 0.75 mL of dimethyl sulfoxide (DMSO), stir for 30 min to obtain a mixed solution.

[0047] Step 2: Place the mixed solution obtained in Step 1 in a 90℃ oven and heat continuously for 96 hours to obtain white transparent block crystals. After washing, filtering, drying and grinding, the white transparent block crystals are used to obtain the iron ion detection fluorescent probe. The molecular formula of the iron ion detection fluorescent probe is (Zn2(C8O8N2H2)·DMSO·HCOOH). n .

[0048] Step 3: Prepare a series of iron ion standard solutions with known concentrations of 0 μM, 10 μM, 20 μM, 30 μM, 40 μM, 50 μM, and 60 μM.

[0049] Step 4: Take 1 mg of the iron ion detection fluorescent probe obtained in Step 2, add 3 mL of the iron ion standard solution of known concentration prepared in Step 3, mix well, and measure its fluorescence intensity at a wavelength of 320 nm.

[0050] Figure 7 This is a fluorescence change graph showing the addition of 3 mL of iron ion standard solutions of different concentrations to the iron ion detection fluorescent probe. From... Figure 7 It can be clearly seen that as the concentration of iron ions increases, the fluorescence intensity of the iron ion detection fluorescent probe gradually decreases.

[0051] like Figure 8 As shown, within the low iron ion concentration range of 0 μM to 300 μM, the linear relationship between the fluorescence intensity of the iron ion detection fluorescent probe and the ion concentration conforms to the Stern-Volme equation: I0 / I = 1 + K SV [M]; I0 represents the fluorescence intensity before the addition of iron ions, I represents the fluorescence intensity after the addition of iron ions, [M] represents the concentration of the analyte (μmol / L, μM), K SVRepresents the quenching constant (μM) -1 ).

[0052] The limit of detection (LOD) formula is: LOD = 3σ / K SV K SV =0.01203μM -1 The detection limit of this iron ion fluorescent probe was calculated to be 1.10 μM. Here, σ is the standard deviation of the fluorescence intensity in 10 blank experiments without any added ions; in this example, σ = 0.0044.

[0053] Accurately weigh 0.5 g of dried magnesium oxide into a 75 mL platinum dish. Add 4.0 g of anhydrous sodium carbonate and 2.7 g of boric acid, mix thoroughly, cover with a platinum cap (leaving a slight gap), and place in a high-temperature furnace. Heat slowly at first, then gradually increase the temperature to 1100℃±25℃ and heat for 10 min. Remove the crucible and cover with a platinum cap or watch glass. After the crucible has cooled slightly, add 55 mL of sulfuric acid (1+9) while stirring. Heat in a steam bath until the sample is completely dissolved. After cooling, transfer to a 250 mL volumetric flask and dilute to volume for later use.

[0054] At this point, if the iron ion content of the sample meets the industry standard, the iron content should be ≤0.5%, which, according to formulas 1 and 2 below, translates to a concentration less than 125.24 μM. The detection limit of the iron ion fluorescent probe prepared in this embodiment is 1.09 μM < 125.24 μM. Furthermore, anti-interference experiments have demonstrated that this iron ion detection fluorescent probe is less affected by interference from other ions, proving that it can quickly screen magnesium oxide with iron content meeting industry standard requirements.

[0055] Formula 1: Fe2O3+3H2SO4=Fe2(SO4)3+3H2O;

[0056] Formula 2:

[0057] M is the relative molecular mass of Fe2O3, with a value of 159.69 g / mol; m is the mass of MgO weighed, with a value of 0.5 g; V is the volume of the solution, with a value of 250 mL; and C is the concentration of iron ions.

[0058] The fluorescence detection method of the present invention has the following advantages compared with the prior art:

[0059] The method of this invention for screening magnesium oxide with iron content meeting industry standards features rapid response, high selectivity, high sensitivity, and visualization. It enables rapid detection of iron ions through changes in fluorescence. Compared to existing iron ion detection technologies, this iron ion detection reagent is significantly more effective, simpler to operate, and easier to implement, showing promising market application prospects.

[0060] Sulfuric acid (1+9) usually represents the volume ratio of sulfuric acid to water, that is, 1 volume of concentrated sulfuric acid is mixed with 9 volumes of water.

Claims

1. A fluorescent probe for detecting iron ions, characterized in that, The molecular formula of the fluorescent probe is (Zn2(C8O8N2H2)·DMSO·HCOOH). n ; The preparation steps of the fluorescent probe are as follows: Step 1: Weigh pyrazine-2,3,5,6-tetracarboxylic acid and Zn(NO3)2 and dissolve them in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). After stirring, a mixed solution is obtained. The mass ratio of pyrazine-2,3,5,6-tetracarboxylic acid to Zn(NO3)2 is 1:6, and the volume ratio of N,N-dimethylformamide (DMF) to dimethyl sulfoxide (DMSO) is 3:

1. Step 2: Place the mixed solution obtained in Step 1 in an oven at 90℃±5℃ and heat continuously for 4-6 days to obtain white transparent block crystals. After washing, filtering, drying and grinding the white transparent block crystals, the fluorescent probe is obtained.

2. The fluorescent probe for iron ion detection according to claim 1, characterized in that, The stirring time in step one is 30-60 minutes.

3. The application of the iron ion detection fluorescent probe as described in claim 1 in the rapid detection of iron content in magnesium oxide.

4. A rapid fluorescence detection method for detecting iron content in magnesium oxide, characterized in that, Includes the following steps: Step 1: Weigh 0.5g of dried magnesium oxide into a platinum crucible. Add 4.0g of anhydrous sodium carbonate and 2.7g of boric acid to the platinum crucible and mix well. Cover with a platinum lid, leaving a slight gap, and place in a high-temperature furnace. First, heat slowly, then gradually increase the temperature to 1100℃±25℃ and heat for 10 minutes. Remove the crucible and cover it with a platinum lid or watch glass. After the crucible has cooled slightly, add 55mL of sulfuric acid solution while stirring. Heat in a steam bath until the sample is completely dissolved. After cooling, transfer to a volumetric flask and dilute to volume to obtain a magnesium oxide solution. Step 2: Take 1 mg of the iron ion detection fluorescent probe from claim 1, add 3 mL of the magnesium oxide solution prepared in step 1, mix well, and measure the fluorescence intensity of the iron ion detection fluorescent probe at an excitation wavelength of 290 nm.

5. The rapid fluorescence detection method for detecting iron content in magnesium oxide according to claim 4, characterized in that, In step one, the volume ratio of sulfuric acid to water in the sulfuric acid solution is 1:9.

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