Rapid detection method for ferric ions in water

Abstract

The invention belongs to the technical field of iron ion detection, and particularly relates to a rapid detection method for ferric ions in water, which comprises the following steps: a fluorescent probe preparation step: taking trihydrate of copper nitrate and tryptamine, adding into a centrifuge tube in sequence, adding ultrapure water, performing ultrasonic dissolution, transferring into a high-pressure reaction kettle, and performing hydrothermal reaction to obtain a fluorescent probe; cooling to room temperature, centrifuging the obtained yellow green solution in a centrifugal machine, and filtering the supernate through a microfiltration membrane to obtain a copper-doped carbon quantum dot CuCDs stock solution, namely the fluorescent probe; analyzing and determining Fe < 3 + >: taking the diluent of the prepared CuCDs solution, adding the diluent into a centrifugal tube containing a Fe < 3 + > standard solution, uniformly mixing, carrying out fluorescent quantitative analysis and detection, and exploring the change rule of the fluorescence intensity ratio of CuCDs; according to the rapid detection method for Fe < 3 + > provided by the invention, the synthesized CuCDs have high sensitivity, can realize on-site rapid detection of Fe < 3 + > in a water medium, and shows a wide application prospect in the field of environmental monitoring.

Description

Technical Field

[0001] This invention belongs to the field of iron ion detection technology, and in particular relates to a rapid detection method for ferric ions in water. Background Technology

[0002] Iron (Fe) is an essential trace element for the human body, playing a vital role in biological processes such as oxygen transport. The human body primarily obtains iron through diet, including heme iron and non-heme iron. Iron absorption is finely regulated in the intestines to maintain iron homeostasis. The main iron ions in the human body are Fe. 2+ and Fe 3+ Fe 3+ It is the main form of iron in food and water. Fe in the blood 3+ Transferrin transports the iron to the bone marrow and liver, where excess iron is stored in hepatosplenic ferritin and reduced to Fe when necessary. 2+ Contains Fe 3+ The proteins in this protein are involved in antibacterial and immune regulation. However, excessive intake of Fe... 3+ This can lead to iron overload, triggering cellular oxidative stress and free radical generation, causing organ damage. Therefore, detecting Fe in an aqueous medium... 3+ It is important to assess iron intake balance, and rapid and effective detection methods need to be developed.

[0003] Traditional Fe 3+ Detection methods include inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS), and ultraviolet-visible spectrophotometry (UV-Vis), but all have limitations and cannot meet modern detection needs, thus restricting practical applications. For example, ICP-MS detection is time-consuming, costly, and complex to operate; while AAS and UV-Vis are cost-effective, their sensitivity, selectivity, and anti-interference capabilities are insufficient. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and to disclose a rapid detection method for ferric ions in water.

[0005] To achieve the aforementioned objective, the present invention provides a rapid detection method for ferric ions in water, the rapid detection method comprising the following steps:

[0006] Fluorescent probe preparation steps: Copper nitrate trihydrate and tryptophan were added to a centrifuge tube, and ultrapure water was added. After ultrasonic dissolution, the solution was transferred to a high-pressure reactor and subjected to hydrothermal reaction. The solution was then cooled to room temperature. The resulting yellow-green solution was centrifuged and the supernatant was filtered through a microporous membrane to obtain a copper-doped carbon quantum dot CuCDs stock solution, which is the fluorescent probe.

[0007] Fe 3+Analytical and determination steps: Take the diluted solution of the prepared CuCDs solution and add it to a solution containing Fe. 3+ The standard solution was mixed in centrifuge tubes and then subjected to quantitative fluorescence analysis to investigate the variation law of the fluorescence intensity ratio of CuCDs.

[0008] Preferably, the rapid detection method further includes:

[0009] Transmission electron microscopy characterization steps: The brownish-yellow CuCDs powder was placed on a copper grid, and the morphology and structure of the synthesized CuCDs were characterized by transmission electron microscopy.

[0010] Preferably, the rapid detection method further includes:

[0011] X-ray diffraction characterization steps: CuCDs are coated onto a clean Si substrate with a smooth surface and strong adhesion to the substrate. The crystal structure of CuCDs is characterized by XRD.

[0012] Preferably, the rapid detection method further includes:

[0013] X-ray photoelectron spectroscopy analysis steps: CuCDs are coated onto a clean Si substrate to form a film, then dried. The elements and valence states of CuCDs are analyzed using XPS.

[0014] Preferably, the rapid detection method further includes:

[0015] Fourier transform infrared spectroscopy analysis procedure: After adding KBr to CuCDs, the sample is made into tablets and the composition of functional groups on the surface of CuCDs is further analyzed by FTIR.

[0016] Preferably, the rapid detection method further includes a reaction system parameter optimization step, which includes:

[0017] Buffer selection steps: Investigate the effects of four buffers, PB, MES, MOPS propanesulfonic acid, and HEPES, on the fluorescence intensity of CuCDs;

[0018] pH optimization steps: Investigate the effect of MES buffer at multiple pH points in the pH range of 3-11 on the fluorescence intensity of CuCDs;

[0019] Optimization steps for reaction temperature: Investigate the effect of multiple temperature points in the reaction system range of 10-80℃ on the fluorescence intensity of CuCDs;

[0020] Reaction time optimization steps: Investigate the effect of reaction time on CuCD fluorescence intensity at multiple time points within the range of 10-60 min;

[0021] Preferably, the rapid detection method further includes:

[0022] Selective analysis steps: Take CuCDs solution, select and prepare solutions of different metal ions, add the metal ion solutions to CuCDs solution respectively, mix well and perform fluorescence analysis, and calculate the fluorescence intensity ratio;

[0023] Performance evaluation steps: Fe 3+ The CuCDs were added to a CuCDs solution for quantitative fluorescence analysis to investigate the change in CuCDs fluorescence signal with the target Fe. 3+ The relationship between concentration changes;

[0024] Actual water sample testing steps: The CuCDs detection method was used to evaluate the Fe content in actual water samples. 3+ The performance of CuCDs was evaluated by fluorescence analysis of water samples after filtration through a filter membrane, and the spiked recovery method was used to assess the detection of Fe in actual water samples. 3+ The performance of the water sample was assessed by fluorescence analysis after filtration through a filter membrane.

[0025] Preferably, the working concentration of CuCDs is 1.00-1.50 mg / mL.

[0026] Preferably, in the selective analysis step, the metal ions include Na. + K + Ag + Mg 2+ Mn 2+ Ca 2+ Cd 2+ Cu 2+ Zn 2+ Al 3+ Cr 3+ and Fe 3+ Any one of them.

[0027] Preferably, the concentration of the diluent for the CuCDs solution is 1.00–1.50 mg / mL.

[0028] The technical solution provided by this invention has at least the following technical effects:

[0029] Copper nitrate trihydrate (Cu(NO3)2·3H2O) and tryptamine (C 10 H 12 N2) was used as the raw material for synthesis, and Fe was selected. 3+ As an aptamer targeting CuCDs, experimental results show that CuCDs synthesized via a one-step hydrothermal method exhibit dual emission peaks at 336 nm and 395 nm under 290 nm excitation light and show blue fluorescence under ultraviolet light. When Fe is added to CuCDs... 3+Subsequently, its blue fluorescence was quenched. With Fe... 3+ As the concentration increases, the fluorescence color gradually fades from an initial blue to nearly colorless. Based on this phenomenon, the Fe proposed in this invention... 3+ A rapid detection method was developed, and the synthesized CuCDs exhibited high sensitivity, enabling the detection of Fe in aqueous media. 3+ Rapid on-site detection has shown broad application prospects in the field of environmental monitoring. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 The morphology and crystal structure of CuCDs are characterized using TEM and XRD in embodiments of the present invention.

[0032] Figure 2 XPS was used to analyze the elemental composition and valence state diagram of CuCDs in an embodiment of the present invention;

[0033] Figure 3 This is a surface functional group composition diagram of CuCDs analyzed using FTIR in an embodiment of the present invention;

[0034] Figure 4 The emission spectrum and UV-Vis absorption and fluorescence spectra of CuCDs in the embodiments of the present invention are shown below.

[0035] Figure 5 The figures show the F0 / F values ​​of CuCDs solutions after adding different metal ions and the fluorescence images of CuCDs solutions with different metal ions under ultraviolet light in the embodiments of the present invention.

[0036] Figure 6 This is a graph showing the relationship between the fluorescence quenching degree F0 / F value of CuCDs dual emission peaks and their concentration in an embodiment of the present invention. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0038] This embodiment discloses a rapid detection method for ferric ions in water, the rapid detection method comprising the following steps:

[0039] Fluorescent probe preparation steps: Take 0.10 g of copper nitrate trihydrate (Cu(NO3)2·3H2O) and 0.10 g of tryptamine (C 10 H 12 N2) was added to 50 mL centrifuge tubes; 20 mL of ultrapure water was added, and the mixture was dissolved by sonication and transferred to a 40 mL high-pressure reactor. The reactor was then placed at 180 °C for hydrothermal reaction for 6 h. The reactor was removed and cooled to room temperature. The resulting yellow-green solution was centrifuged at 10,000 rpm for 10 min. The supernatant was then filtered through a 0.22 μm microporous membrane to obtain the fluorescent probe, namely the copper-doped carbon quantum dot (CuCDs) stock solution.

[0040] Fe 3+ Analytical determination procedure: Take 180 μL of the diluted CuCDs solution prepared above (concentration of 1.32 mg / mL) and add it to a solution containing 20 μL of Fe. 3+ The standard solution (or actual water sample) was mixed in a 1.5 mL centrifuge tube and then subjected to quantitative fluorescence analysis with an excitation wavelength of 290 nm to investigate the variation law of the fluorescence intensity ratio (F0 / F) of CuCDs.

[0041] Specifically, it also includes characterization and analysis steps for the fluorescent probe CuCDs:

[0042] like Figure 1 As shown, the transmission electron microscopy (TEM) characterization steps are as follows: Transmission electron microscopy (TEM) characterization: The brownish-yellow CuCDs powder was placed on a copper grid, and the morphology and structure of CuCDs were characterized by TEM.

[0043] like Figure 1 As shown, the X-ray diffraction (XRD) characterization steps are as follows: CuCDs are coated on a clean Si substrate with a thickness of about 20 nm. The surface is flat and the CuCDs are firmly bonded to the substrate. The crystal structure of CuCDs is characterized by XRD.

[0044] like Figure 2 As shown, the X-ray photoelectron spectroscopy (XPS) analysis steps are as follows: CuCDs are coated onto a clean Si substrate to form a film with a thickness of 1-2 drops, and then dried. The elemental composition and valence state of CuCDs are analyzed using XPS.

[0045] like Figure 3 , Figure 4 As shown, Fourier transform infrared spectroscopy (FTIR) analysis: After adding KBr to CuCDs, the sample was made into tablets and the composition of functional groups on the surface of CuCDs was further analyzed by FTIR.

[0046] Optimization steps for reaction system parameters: Buffer selection step: Investigate the effects of four buffers on the fluorescence intensity of CuCDs: PB (phosphate), MES (2-(N-morpholine) ethanesulfonic acid), MOPS (3-(N-morpholine) propanesulfonic acid), and HEPES (4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid);

[0047] pH optimization steps: Investigate the effect of MES buffer on the fluorescence intensity of CuCDs at 9 pH points from pH 3 to 11;

[0048] Optimization steps for reaction temperature: Investigate the effect of reaction system temperature at 7 temperature points ranging from 10 to 80℃ on the fluorescence intensity of CuCDs;

[0049] Optimization steps for reaction time: Investigate the effect of reaction time on the fluorescence intensity of CuCDs at 8 time points ranging from 10 to 60 min.

[0050] like Figure 5 As shown, the selective analysis procedure is as follows: 180 μL of CuCDs solution was taken, and 10 mM solutions of different metal ions (Na+, Na ... + K + Ag + Mg 2+ Mn 2+ Ca 2+ Cd 2+ Cu 2+ Zn 2+ Al 3+ Cr 3+ Fe 3+ ) solution, add 20 μL of the above metal ion solution to CuCDs solution, mix well and perform fluorescence analysis, calculate the fluorescence intensity ratio (F0 / F).

[0051] like Figure 6 As shown, the method analyzes the performance evaluation steps: 0-1000μM Fe 3+ The CuCDs were added to a CuCDs solution for quantitative fluorescence analysis to investigate the fluorescence signal of CuCDs as a function of the target Fe. 3+ The relationship between concentration changes.

[0052] Actual water sample testing steps: The CuCDs detection method was used to evaluate the Fe content in actual water samples. 3+ The performance was assessed using Minjiang River water as a sample, which was filtered through a 0.22 μm filter membrane and then subjected to fluorescence analysis.

[0053] Table 1: Fe in water samples 3+ Test results

[0054]

[0055]

[0056] As shown in the table above, the recovery rate was 84.9%–118.6%, which is similar to the results of the AAS standard method, indicating that the method is feasible and has good specificity and sensitivity.

[0057] This invention constructs a simple and convenient Fe2+ ionization process by preparing dual-emission CuCDs. 3+ Quantitative detection method. Copper nitrate trihydrate (Cu(NO3)2·3H2O) and tryptophan (C 10 H 12 N2) was used as the raw material for synthesis, and Fe was selected. 3+ As an aptamer targeting CuCDs, experimental results show that CuCDs synthesized via a one-step hydrothermal method exhibit dual emission peaks at 336 nm and 395 nm under 290 nm excitation light and show blue fluorescence under ultraviolet light. When Fe is added to CuCDs... 3+ Subsequently, its blue fluorescence was quenched. With Fe... 3+ As the concentration increases, the fluorescence color gradually fades from an initial blue to nearly colorless. Based on this phenomenon, the Fe proposed in this invention... 3+ A rapid detection method was developed, and the synthesized CuCDs exhibited high sensitivity, enabling the detection of Fe in aqueous media. 3+ Rapid on-site detection has shown broad application prospects in the field of environmental monitoring.

[0058] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A rapid detection method for ferric ions in water, characterized in that, The rapid detection method includes the following steps: Fluorescent probe preparation steps: Copper nitrate trihydrate and tryptophan were added to a centrifuge tube, and ultrapure water was added. After ultrasonic dissolution, the solution was transferred to a high-pressure reactor and subjected to hydrothermal reaction. The solution was then cooled to room temperature. The resulting yellow-green solution was centrifuged and the supernatant was filtered through a microporous membrane to obtain a copper-doped carbon quantum dot CuCDs stock solution, which is the fluorescent probe. Fe 3+ Analytical and determination steps: Take the diluted solution of the prepared CuCDs solution and add it to a solution containing Fe. 3+ The standard solution was mixed in centrifuge tubes and then subjected to quantitative fluorescence analysis to investigate the variation law of the fluorescence intensity ratio of CuCDs.

2. The method for rapid detection of ferric ions in water according to claim 1, characterized in that, The rapid detection method also includes: Transmission electron microscopy characterization steps: The brownish-yellow CuCDs powder was placed on a copper grid, and the morphology and structure of the synthesized CuCDs were characterized by transmission electron microscopy.

3. The method for rapid detection of ferric ions in water according to claim 2, characterized in that, The rapid detection method also includes: X-ray diffraction characterization steps: CuCDs are coated onto a clean Si substrate with a smooth surface and strong adhesion to the substrate. The crystal structure of CuCDs is characterized by XRD.

4. The method for rapid detection of ferric ions in water according to claim 3, characterized in that, The rapid detection method also includes: X-ray photoelectron spectroscopy analysis steps: CuCDs are coated onto a clean Si substrate to form a film, then dried. The elements and valence states of CuCDs are analyzed using XPS.

5. The method for rapid detection of ferric ions in water according to claim 4, characterized in that, The rapid detection method also includes: Fourier transform infrared spectroscopy analysis procedure: After adding KBr to CuCDs, the sample is made into tablets and the composition of functional groups on the surface of CuCDs is further analyzed by FTIR.

6. The method for rapid detection of ferric ions in water according to claim 1, characterized in that, The rapid detection method further includes a reaction system parameter optimization step, which includes: Buffer selection steps: Investigate the effects of four buffers, PB, MES, MOPS propanesulfonic acid, and HEPES, on the fluorescence intensity of CuCDs; pH optimization steps: Investigate the effect of MES buffer at multiple pH points in the pH range of 3-11 on the fluorescence intensity of CuCDs; Optimization steps for reaction temperature: Investigate the effect of multiple temperature points in the reaction system range of 10-80℃ on the fluorescence intensity of CuCDs; Reaction time optimization steps: Investigate the effect of reaction time on CuCD fluorescence intensity at multiple time points within the range of 10-60 min.

7. The method for rapid detection of ferric ions in water according to claim 1, characterized in that, The rapid detection method also includes: Selective analysis steps: Take CuCDs solution, select and prepare solutions of different metal ions, add the metal ion solutions to CuCDs solution respectively, mix well and perform fluorescence analysis, and calculate the fluorescence intensity ratio; Performance evaluation steps: Fe 3+ The CuCDs were added to a CuCDs solution for quantitative fluorescence analysis to investigate the fluorescence signal of CuCDs as a function of the target Fe. 3+ The relationship between concentration changes; Actual water sample testing steps: The CuCDs detection method was used to evaluate the Fe content in actual water samples. 3+ The performance of CuCDs was evaluated by fluorescence analysis of water samples after filtration through a filter membrane, and the spiked recovery method was used to assess the detection of Fe in actual water samples. 3+ The performance of the water sample was assessed by fluorescence analysis after filtration through a filter membrane.

8. The method for rapid detection of ferric ions in water according to claim 1, characterized in that, The working concentration of the CuCDs is 1.00-1.50 mg / mL.

9. The method for rapid detection of ferric ions in water according to claim 7, characterized in that, In the selective analysis step, the metal ions include Na. + K + Ag + Mg 2+ Mn 2+ Ca 2+ Cd 2+ Cu 2+ Zn 2+ Al 3+ Cr 3+ and Fe 3+ Any one of them.

10. The method for rapid detection of ferric ions in water according to claim 1, characterized in that, The concentration of the diluent for the CuCDs solution is 1.00–1.50 mg / mL.

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