Preparation method of cobalt modified polyheptazine imide and application thereof in rhodamine b photosensitized detection of paracetamol

Abstract

The application relates to a preparation method of cobalt-modified polyheptazine imide and application thereof in rhodamine B photosensitization detection of paracetamol, and relates to the technical field of visual super-sensitive detection of colorless paracetamol. Method: the cobalt-modified polyheptazine imide is used to detect paracetamol in the following modes: mode one, rhodamine B-cobalt-modified polyheptazine imide is uniformly mixed with a paracetamol solution to obtain a to-be-detected suspension; the suspension is stirred and adsorbed in a Porphyrin multi-channel photocatalytic reactor under the condition of no light, a filter membrane is used for filtration after 532nm visible light is turned on, and ultraviolet-visible spectrophotometry is used for detection; mode two, the to-be-detected suspension is injected into a liquid-core optical fiber probe and is packaged, then a 532nm single-wavelength light source is turned on, and light irradiation is performed for 3-5min. The application can obtain the preparation method of cobalt-modified polyheptazine imide and application thereof in rhodamine B photosensitization detection of paracetamol.

Description

Preparation method of cobalt-modified polyheptamethrinimide and its application in the photosensitization detection of acetaminophen by rhodamine B. Technical Field

[0001] This invention relates to the field of visual ultrasensitive detection technology for colorless paracetamol, specifically to the preparation method of cobalt-modified polyheptamethrinimide and its application in the photosensitization detection of paracetamol using Rhodamine B. Background Technology

[0002] Paracetamol, a widely used nonsteroidal anti-inflammatory drug (NSAID) and analgesic globally, can enter the aquatic environment through various channels, including pharmaceutical wastewater and human and animal metabolism. Due to its widespread use and bioaccumulation, paracetamol is one of the most frequently detected pharmaceutical pollutants in water bodies. Although the concentration of paracetamol in aquatic ecosystems is lower than that used for therapeutic purposes, its poor biodegradability and long-term exposure to aquatic systems can have negative impacts on organisms. Excessive use or accumulation of paracetamol can cause hepatotoxicity, kidney failure, and even nephrotoxicity. Because of its high and continuously increasing usage and its persistent nature, paracetamol has become one of the most frequently detected emerging pharmaceutical and personal care product (PPCP) pollutants in global aquatic ecosystems. Studies show that the global average detection concentration is generally at the microgram or nanogram level, and long-term accumulation poses a serious threat to aquatic ecosystems. Therefore, rapid and ultrasensitive detection of paracetamol is of great significance for environmental monitoring and the protection of ecology and human health.

[0003] Currently, the common detection methods for paracetamol include chromatography, mass spectrometry, and Raman spectroscopy. Chromatography is based on the differences in the physicochemical properties of paracetamol in a mixture within a stationary phase and a mobile phase (usually methanol or acetonitrile). The interaction between the two phases leads to different residence times, enabling separation and detection. Mass spectrometry is based on the ionization of paracetamol in an ion source, generating ions with different charge-to-mass ratios. These ions are accelerated by an electric field to form an ion beam, which enters a mass analyzer. The different mass-to-nucleus ratios obtained in the mass analyzer are used to test paracetamol. Raman spectroscopy analyzes paracetamol by recording its light scattering absorption spectrum after a beam of infrared light is irradiated onto it. It can only perform qualitative analysis and is difficult to perform quantitative analysis. Therefore, all of these methods require specialized, large-scale detection equipment, complex pretreatment processes, toxic organic solvents such as methanol and acetonitrile, and demanding operational skills from testing personnel. They also cannot achieve rapid on-site detection and have long detection cycles. Therefore, there is a need to develop an in-situ, sensitive, long-distance, and visual detection method. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems by providing a method for preparing cobalt-modified polyheptamethrin imide and its application in the photosensitization detection of acetaminophen by rhodamine B.

[0005] The preparation method of cobalt-modified polyheptamethrin imide is carried out according to the following steps:

[0006] Step S1:

[0007] Melamine and cyanuric acid were added separately to deionized water and stirred at 50-100℃ until completely dissolved, yielding solutions A and B respectively. Solution B was added to solution A at 50-100℃ and stirred until homogeneous, yielding mixture C. After heating and stirring for 20-40 minutes, potassium thiocyanate was added, and heating and stirring continued for another 20-40 minutes. Then, cobalt nitrate was added, and heating and stirring continued for 1.5-3 hours. After heating and stirring, the mixture was cooled, centrifuged, and the supernatant was discarded. The white particles were collected, washed, dried, and ground to obtain powder D.

[0008] Step S2:

[0009] Under nitrogen protection, powder D obtained in step S1 is placed in a tube furnace and heated to 500-550℃, and calcined at 500-550℃ for 3-5 hours. After calcination, it is naturally cooled to room temperature to obtain a sample after the first calcination. The sample after the first calcination is placed in a tube furnace again and heated to 450-510℃ under air conditions, and calcined at 450-510℃ for 1.5-3 hours. After calcination, it is naturally cooled to room temperature to obtain a sample after the second calcination. The sample after the second calcination is then reacted with chlorine... Potassium chloride and lithium chloride were mixed and ground, then placed in a tube furnace and heated to 530–570 °C under nitrogen protection, and calcined at 530–570 °C for 3.5–4.5 h. After calcination, the mixture was allowed to cool naturally to room temperature to obtain a calcined molten salt sample. The calcined molten salt sample was added to a nitric acid solution and stirred in a water bath at 60–80 °C for 1–2 h. After cooling, the sample was centrifuged, the supernatant was discarded, and the remaining solid was collected, washed, dried, and then dispersed in deionized water to prepare a solution with a concentration of 1.0–3.0 g·L⁻¹. -1 Cobalt-modified polyheptamethimide (PHI).

[0010] Application of cobalt-modified polyheptamethrinimide in the photosensitization of paracetamol using Rhodamine B: Paracetamol was detected using cobalt-modified polyheptamethrinimide in any of the following methods:

[0011] Method 1:

[0012] The concentration is 1.0~3.0 g·L -1 Cobalt-modified polyheptamethrinimide with a concentration of 1-8 mg·L -1After the rhodamine B solution was mixed evenly, rhodamine B-cobalt modified polyheptamethrin imide was obtained; the volume ratio of the cobalt modified polyheptamethrin imide to the rhodamine B solution was (0.5~1.0):(0.5~1.0).

[0013] Rhodamine B-cobalt modified polyheptamethrin imide was mixed evenly with acetaminophen solution to obtain the test suspension. The test suspension was placed in a Pofil multi-channel photocatalytic reactor and stirred for 4-7 min under no light conditions. Then, 532 nm visible light was turned on and the solution was irradiated for 3-5 min. After filtration, the solution was filtered using a 22 μm aqueous phase filter membrane. The filtrate was then detected using a UV-Vis spectrophotometer to complete the detection of acetaminophen with rhodamine B-cobalt modified polyheptamethrin imide.

[0014] Method 2:

[0015] The concentration is 1.0~3.0 g·L -1 Cobalt-modified polyheptamethrinimide with a concentration of 1-8 mg·L -1 After the rhodamine B solution was mixed evenly, rhodamine B-cobalt modified polyheptamethrin imide was obtained; the volume ratio of the cobalt modified polyheptamethrin imide to the rhodamine B solution was (0.5~1.0):(0.5~1.0).

[0016] Rhodamine B-cobalt modified polyheptamethrin imide was mixed evenly with acetaminophen solution to obtain the test suspension. The volume ratio of rhodamine B solution, cobalt modified polyheptamethrin imide and acetaminophen solution in the rhodamine B-cobalt modified polyheptamethrin imide was (0.5~1.0):(0.5~1.0):0.2. The test suspension was injected into the liquid-core fiber optic probe using a syringe and then sealed. The liquid-core fiber optic probe was connected to the HOURS-532 light source, and then the 532nm single-wavelength light source was turned on and irradiated for 3~5 minutes to complete the detection of acetaminophen with rhodamine B-cobalt modified polyheptamethrin imide.

[0017] The fabrication method of the liquid-core fiber optic probe is carried out according to the following steps:

[0018] Step 1:

[0019] Polyethylene glycol acrylate and 2-hydroxy-2-methyl-1-phenyl-1-propanone were added to deionized water and ultrasonically mixed to obtain a hydrogel solution.

[0020] Step Two:

[0021] A silicone tube with an inner diameter of 3 mm is fitted over a silicone tube with an inner diameter of 1 mm. Then, the hydrogel solution obtained in step one is injected into the sandwich formed by the two silicone tubes. After curing with a 365 nm UV lamp, the inner and outer silicone tubes are removed to obtain a tubular hydrogel layer.

[0022] Step 3:

[0023] The quartz optical fiber is inserted into the tubular hydrogel layer obtained in step two. After curing, it is then alternately soaked in sodium alginate solution and calcium chloride solution to obtain a liquid-core optical fiber probe.

[0024] The principle of this invention:

[0025] Rhodamine B, an oxanthracene dye with vibrant color, possesses unique spirocyclic transformation properties, allowing for rapid conversion between open-ring and closed-ring structures under certain conditions. Figure 1 illustrates this spirocyclic transformation characteristic of RhB, leading to color changes and making it an ideal probe for developing rapid, visual detection systems. More interestingly, under visible light irradiation, RhB can photosensitize a semiconductor, causing the excited-state electrons of the dye to rapidly transfer to the lower energy level of the semiconductor's conduction band (CB). Upon losing electrons, RhB transforms from a colored open-ring structure to a colorless closed-ring structure, thus inducing rapid photosensitization and decolorization. Based on this property, if the semiconductor can competitively adsorb paracetamol, paracetamol can block electron transfer between the dye RhB and the semiconductor, thereby inhibiting the photosensitization and decolorization process of RhB and achieving a color change. Therefore, utilizing the degree of inhibition of RhB photosensitization and decolorization by paracetamol in the RhB-semiconductor photosensitization system holds promise for establishing a novel visual detection method for paracetamol.

[0026] Another core component of the photosensitization detection system is a semiconductor that matches the RhB energy level. The lowest empty orbital level (LUMO) of the RhB dye should be more negative than the CB of the semiconductor, thermodynamically enabling electron injection into the semiconductor. The emerging two-dimensional carbon nitride-based nanomaterial, polyheptamethrinimide (PHI), possesses suitable semiconductor band-edge positions, readily accepting photoexcited electrons from the RhB dye. Its high crystallinity and two-dimensional layered structure further facilitate surface charge transport, thus promoting photosensitization and decolorization. Furthermore, the PHI surface has abundant active sites and easily tunable electronic structures, which can be used to provide precise selective adsorption sites for paracetamol through structural regulation or modification, making it an ideal semiconductor material for paracetamol photosensitization detection systems. Therefore, exploring and establishing novel RhB-PHI photosensitization detection methods holds promise for achieving rapid, visualized, highly sensitive, and highly selective detection of paracetamol.

[0027] Fiber optic probes are target detection tools based on optical signal sensing and quantification. They offer advantages such as compact structure, integrated signal transmission and detection, and strong remote detection capabilities. They are also easily combined with conventional physicochemical treatment methods to detect substances that are difficult to detect using other methods, and have been widely used in chemistry, biology, and medicine. However, the modification and corrosion of traditional solid-state optical fibers are complex and time-consuming. Light is mainly concentrated at the fiber end, resulting in scattering and refraction leading to uneven light distribution, and the sensing material and contaminants cannot effectively contact each other within the solid-state fiber. Hydrogel liquid-core optical fibers have a high-refractive-index core and a low-refractive-index cladding structure. Therefore, light can be positioned and transmitted within the hydrogel fiber. By embedding the sensing material into the hydrogel liquid-core optical fiber probe, the sample to be detected is automatically introduced into the core and mixed with the sensing material. The RhB-Co / PHI photosensitization detection system reacts to cause changes in the optical signal, thereby achieving on-site, in-situ, and rapid detection of acetaminophen.

[0028] Based on this, this invention differs from traditional detection methods in principle and procedure, proposing a novel dye-semiconductor photosensitization detection method. Based on the prepared cobalt-modified PHI nanomaterial (Co / PHI) and RhB, a visual detection method for paracetamol is constructed. This sensing material system is encapsulated in a liquid-core fiber optic probe, enabling rapid remote reading of paracetamol concentration data on-site simply by inserting the probe into the test water sample. The specific detection principle is as follows: RhB can photosensitize Co / PHI under visible light irradiation at 532nm. The excited-state electrons of RhB rapidly transfer to the lower energy level conduction band (CB) of Co / PHI. Upon losing electrons, RhB transforms from a colored open-ring structure to a colorless closed-ring structure, thus triggering rapid photosensitization and decolorization of RhB. However, when acetaminophen enhances the competitive selective adsorption of acetaminophen by Co / PHI through coordination with Co on PHI, acetaminophen can block electron transfer between the dye RhB and Co / PHI, thereby inhibiting the photosensitization and decolorization process of RhB, leading to a change in RhB color. Therefore, by utilizing the degree of inhibition of RhB photosensitization and decolorization by acetaminophen in the RhB-Co / PHI photosensitization system, i.e., the change in visible light absorption intensity or color of RhB, a new method for visual detection of acetaminophen can be established. Furthermore, by encapsulating the RhB-Co / PHI sensing system into a hydrogel liquid-core fiber optic probe with a 532nm fiber optic light source, the sample to be tested can be fully and uniformly mixed with the sensing material inside the fiber core. Utilizing the color change of the probe caused by the photosensitization reaction in the liquid-core fiber, the goal of on-site, in-situ, rapid, and remote detection of acetaminophen can be achieved.

[0029] The beneficial effects of this invention are:

[0030] This invention successfully establishes for the first time a portable, visual, and rapid detection system for paracetamol using the RhB-Co / PHI photosensitization system. This system requires only a 532nm single-wavelength light source to irradiate the detection system, and the visual detection of paracetamol can be achieved by observing the degree of color change in the detection system. In this detection system, we synthesized Co / PHI nanomaterials using a novel synthesis method. The interaction between Co introduced onto PHI and paracetamol enhances the selective adsorption and enrichment capacity of paracetamol, thereby improving the selectivity and sensitivity of paracetamol detection.

[0031] Furthermore, compared to traditional solid-state fiber optic probes, whose modification and etching processes are complex and time-consuming, and whose light is mainly concentrated at the fiber end, resulting in uneven light distribution due to scattering and refraction, and the inability of sensing materials and contaminants to effectively contact each other within the solid-state fiber. This patent fabricates a hydrogel liquid-core fiber structure with a high-refractive-index core and a low-refractive-index cladding. Light can be positioned and transmitted within the hydrogel fiber, greatly improving light utilization. Encapsulating RhB-Co / PHI sensing material into the hydrogel liquid-core fiber optic probe allows the sample to be fully and uniformly mixed with the sensing material within the core. Utilizing the color change of the probe caused by the photosensitization reaction within the liquid-core fiber optic probe, and with the aid of a colorimetric card or smartphone, on-site, in-situ, rapid, and remote acetaminophen detection can be achieved.

[0032] This invention provides a method for preparing cobalt-modified polyheptamethrin imide and its application in the photosensitization detection of acetaminophen using Rhodamine B. Attached Figure Description

[0033] Figure 1 shows the spirocyclic transformation characteristics of RhB;

[0034] Figure 2 shows a scanning electron microscope (SEM) image of Co / PHI.

[0035] Figure 3 shows the EDS elemental distribution of Co / PHI;

[0036] Figure 4 shows the X-ray diffraction pattern (XRD) of Co / PHI.

[0037] Figure 5 shows the Fourier transform infrared spectrum (FT-IR) of Co / PHI.

[0038] Figure 6 shows the trend of RhB photosensitization decolorization concentration as the illumination time increases;

[0039] Figure 7 shows the UV-Vis absorption spectra of RhB when different concentrations of acetaminophen were added to the RhB-Co / PHI detection system;

[0040] Figure 8 shows the logarithm of the RhB blocking rate lg( IA graph showing the linear fit between ) and the logarithm lg[c] of acetaminophen concentration;

[0041] Figure 9 shows the effect of adding several potential interfering substances to the RhB-Co / PHI system on the detection of paracetamol;

[0042] Figure 10 shows the change in the blocking effect of paracetamol on sensitization and decolorization as the concentration of paracetamol added to the system increases;

[0043] Figure 11 shows a standard color chart made according to different concentrations of acetaminophen and their corresponding fiber optic probe colors;

[0044] Figure 12 shows a diagram of the fiber optic detection device for paracetamol in this invention;

[0045] Figure 13 shows a physical image of the liquid-core optical fiber cladding in this invention;

[0046] Figure 14 shows a schematic diagram of the liquid-core optical fiber in this invention;

[0047] Figure 15 shows a physical diagram of the liquid-core optical fiber and its testing process in this invention.

[0048] Figure 16 shows the invention lg(C) 扑热息痛 The relationship between brightness and lightness. Detailed Implementation

[0049] Specific Implementation Method 1: The preparation method of cobalt-modified polyheptamethrin imide in this implementation method is carried out according to the following steps:

[0050] Step S1:

[0051] Melamine and cyanuric acid were added separately to deionized water and stirred at 50-100℃ until completely dissolved, yielding solutions A and B respectively. Solution B was added to solution A at 50-100℃ and stirred until homogeneous, yielding mixture C. After heating and stirring for 20-40 minutes, potassium thiocyanate was added, and heating and stirring continued for another 20-40 minutes. Then, cobalt nitrate was added, and heating and stirring continued for 1.5-3 hours. After heating and stirring, the mixture was cooled, centrifuged, and the supernatant was discarded. The white particles were collected, washed, dried, and ground to obtain powder D.

[0052] Step S2:

[0053] Under nitrogen protection, powder D obtained in step S1 is placed in a tube furnace and heated to 500-550℃, and calcined at 500-550℃ for 3-5 hours. After calcination, it is naturally cooled to room temperature to obtain a sample after the first calcination. The sample after the first calcination is placed in a tube furnace again and heated to 450-510℃ under air conditions, and calcined at 450-510℃ for 1.5-3 hours. After calcination, it is naturally cooled to room temperature to obtain a sample after the second calcination. The sample after the second calcination is then reacted with chlorine... Potassium chloride and lithium chloride were mixed and ground, then placed in a tube furnace and heated to 530–570 °C under nitrogen protection, and calcined at 530–570 °C for 3.5–4.5 h. After calcination, the mixture was allowed to cool naturally to room temperature to obtain a calcined molten salt sample. The calcined molten salt sample was added to a nitric acid solution and stirred in a water bath at 60–80 °C for 1–2 h. After cooling, the sample was centrifuged, the supernatant was discarded, and the remaining solid was collected, washed, dried, and then dispersed in deionized water to prepare a solution with a concentration of 1.0–3.0 g·L⁻¹. -1 Cobalt-modified polyheptamethine imide.

[0054] Specific Implementation Method Two: The difference between this implementation method and Specific Implementation Method One is that the ratio of the mass of melamine, the mass of cyanuric acid and the volume of deionized water in step S1 is (8~13) g: (3~5) g: (300~550) mL; the mass ratio of melamine, cyanuric acid, potassium thiocyanate and cobalt nitrate in step S1 is (8~11): (3~5): (0.2~0.3): (0.2~0.3).

[0055] The other steps are the same as in Specific Implementation Method 1.

[0056] Specific Implementation Method 3: The difference between this implementation method and Specific Implementation Method 1 or 2 is that: in step S1, the centrifugation speed is 3000~5000 r / min, and the centrifugation time is 3~7 min; the cleaning is done by washing with deionized water and anhydrous ethanol 3~5 times each; the drying temperature is 50~80℃.

[0057] The other steps are the same as in specific implementation method one or two.

[0058] Specific Implementation Method Four: The difference between this implementation method and Specific Implementation Methods One to Three is as follows: In step S2, nitrogen protection means that the nitrogen gas introduction rate is 120~180mL / min; in step S2, the temperature is raised to 500~550℃ at a heating rate of 1~3℃ / min; in step S2, the temperature is raised to 450~510℃ at a heating rate of 4~6℃ / min under air conditions; in step S2, the temperature is raised to 530~570℃ at a heating rate of 4~6℃ / min under nitrogen protection.

[0059] The other steps are the same as those in Specific Implementation Methods One to Three.

[0060] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: in step S2, the mass ratio of the sample after secondary calcination, potassium chloride, and lithium chloride is (0.3~0.6):(0.4~0.45):(0.3~0.35); the mass ratio of the sample after molten salt calcination to the volume of nitric acid solution in step S2 is (0.5~0.8) g:(50~80) mL, and the concentration of the nitric acid solution is 3~6 mol·L⁻¹. -1 .

[0061] The other steps are the same as those in Specific Implementation Methods One through Four.

[0062] Specific Implementation Method Six: The difference between this implementation method and Specific Implementation Methods One to Five is that: in step S2, after cooling, centrifuge at a speed of 3000~5000r / min for 4~6min; in step S2, the washing is done by washing with deionized water and anhydrous ethanol 3~5 times each; the drying temperature is 40~70℃.

[0063] The other steps are the same as those in Specific Implementation Methods 1 to 5.

[0064] Specific Implementation Method Seven: This implementation method involves the application of cobalt-modified polyheptamethrinimide in the photosensitization detection of acetaminophen using Rhodamine B. The cobalt-modified polyheptamethrinimide is used to detect acetaminophen in any of the following ways:

[0065] Method 1:

[0066] The concentration is 1.0~3.0 g·L -1 Cobalt-modified polyheptamethrinimide with a concentration of 1-8 mg·L -1 After the rhodamine B solution was mixed evenly, rhodamine B-cobalt modified polyheptamethrin imide was obtained; the volume ratio of the cobalt modified polyheptamethrin imide to the rhodamine B solution was (0.5~1.0):(0.5~1.0).

[0067] Rhodamine B-cobalt modified polyheptamethrin imide was mixed evenly with acetaminophen solution to obtain the test suspension. The test suspension was placed in a Pofil multi-channel photocatalytic reactor and stirred for 4-7 min under no light conditions. Then, 532 nm visible light was turned on and the solution was irradiated for 3-5 min. After filtration, the solution was filtered using a 22 μm aqueous phase filter membrane. The filtrate was then detected using a UV-Vis spectrophotometer to complete the detection of acetaminophen with rhodamine B-cobalt modified polyheptamethrin imide.

[0068] Method 2:

[0069] The concentration is 1.0~3.0 g·L -1 Cobalt-modified polyheptamethrinimide with a concentration of 1-8 mg·L-1 After the rhodamine B solution was mixed evenly, rhodamine B-cobalt modified polyheptamethrin imide was obtained; the volume ratio of the cobalt modified polyheptamethrin imide to the rhodamine B solution was (0.5~1.0):(0.5~1.0).

[0070] Rhodamine B-cobalt modified polyheptamethrin imide was mixed evenly with acetaminophen solution to obtain the test suspension. The volume ratio of rhodamine B solution, cobalt modified polyheptamethrin imide and acetaminophen solution in the rhodamine B-cobalt modified polyheptamethrin imide was (0.5~1.0):(0.5~1.0):0.2. The test suspension was injected into the liquid-core fiber optic probe using a syringe and then sealed. The liquid-core fiber optic probe was connected to the HOURS-532 light source, and then the 532nm single-wavelength light source was turned on and irradiated for 3~5 minutes to complete the detection of acetaminophen with rhodamine B-cobalt modified polyheptamethrin imide.

[0071] Specific Implementation Method Eight: The difference between this implementation method and Specific Implementation Method Seven is that the volume of the Rhodamine B aqueous solution is 5-8 mL, and the concentration is 1-3 mg·L⁻¹. -1 The cobalt-modified polyheptamethrin imide suspension has a volume of 2-4 mL and a concentration of 1-2.5 g·L⁻¹. -1 The volume of the paracetamol aqueous solution is 0.5~2mL.

[0072] The other steps are the same as in Specific Implementation Method Seven.

[0073] Specific Implementation Method Nine: The preparation method of the liquid-core fiber optic probe in this implementation method is carried out according to the following steps:

[0074] Step 1:

[0075] Polyethylene glycol acrylate and 2-hydroxy-2-methyl-1-phenyl-1-propanone were added to deionized water and ultrasonically mixed to obtain a hydrogel solution.

[0076] Step Two:

[0077] A silicone tube with an inner diameter of 3 mm is fitted over a silicone tube with an inner diameter of 1 mm. Then, the hydrogel solution obtained in step one is injected into the sandwich formed by the two silicone tubes. After curing with a 365 nm UV lamp, the inner and outer silicone tubes are removed to obtain a tubular hydrogel layer.

[0078] Step 3:

[0079] The quartz optical fiber is inserted into the tubular hydrogel layer obtained in step two. After curing, it is then alternately soaked in sodium alginate solution and calcium chloride solution to obtain a liquid-core optical fiber probe.

[0080] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that: the volume ratio of polyethylene glycol acrylate, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and deionized water in step one is (2~4):(0.3~0.5):(4~6); the ultrasonic time in step one is 20~50 min; the mass fraction of sodium alginate in the sodium alginate solution in step three is 1~5%, and the concentration of the calcium chloride solution is 0.05~2 mol·L⁻¹. -1 .

[0081] The other steps are the same as in Specific Implementation Method Nine.

[0082] The beneficial effects of the present invention are verified using the following embodiments:

[0083] Example 1:

[0084] I. The preparation method of cobalt-modified polyheptamethrin imide is carried out according to the following steps:

[0085] Step S1:

[0086] 10g of melamine and 4g of cyanuric acid were added to 500mL of deionized water and stirred at 80℃ until completely dissolved, yielding solutions A and B respectively. Solution B was added to solution A at 80℃ and stirred until homogeneous, resulting in water-insoluble white granules. After heating and stirring for 30min, 0.2526g of potassium thiocyanate was added, and heating and stirring continued for another 30min. Then, 0.2278g of cobalt nitrate was added, and heating and stirring continued for 2h. After heating and stirring, the mixture was cooled and centrifuged at 4000r / min for 5min. The supernatant was discarded, and the white granules were collected and washed three times each with deionized water and anhydrous ethanol. The mixture was then dried in a 60℃ oven and ground to obtain powder D.

[0087] Step S2:

[0088] Under nitrogen protection (inlet rate of 150 mL / min), powder D obtained in step S1 was compacted in a covered ceramic boat, sealed with aluminum foil, and placed in a tube furnace. It was heated to 520°C at a heating rate of 1°C / min and calcined at 520°C for 4 hours. After calcination, it was allowed to cool naturally to room temperature to obtain the sample after one calcination. The sample after one calcination was loosened, uncovered, wrapped with perforated aluminum foil, and placed back in a tube furnace. It was heated to 500°C under air conditions at a heating rate of 5°C / min and calcined at 500°C. The sample was calcined for 2 hours under the following conditions: after calcination, it was naturally cooled to room temperature to obtain the sample after secondary calcination; 0.5 g of the sample after secondary calcination was mixed with 0.4125 g of potassium chloride and 0.3375 g of lithium chloride and ground, then placed in a covered ceramic boat wrapped with aluminum foil inside and out, and then placed in a tube furnace. Under nitrogen protection, the temperature was increased to 550 °C at a heating rate of 5 °C / min, and calcined at 550 °C for 4 hours; after calcination, it was naturally cooled to room temperature to obtain the sample after molten salt calcination; 0.7 g of the sample after molten salt calcination was added to 70 mL of a 5 mol·L⁻¹ solution. -1 The solution was stirred in a water bath at 70°C for 1.5 hours. After cooling, it was centrifuged at 4000 rpm for 5 minutes. The supernatant was discarded, and the remaining solid was collected. It was washed five times each with deionized water and anhydrous ethanol, dried in an oven at 60°C, and then prepared to a concentration of 1.0 g·L⁻¹. -1 Cobalt-modified polyheptamethine imide solution.

[0089] II. The preparation method of the liquid-core fiber optic probe is carried out according to the following steps:

[0090] Step 1:

[0091] Add 3g of polyethylene glycol acrylate and 0.36g of 2-hydroxy-2-methyl-1-phenyl-1-propanone to 5mL of deionized water, and sonicate for 30min until well mixed to obtain a hydrogel solution.

[0092] Step Two:

[0093] A silicone tube with an inner diameter of 3 mm is fitted over a silicone tube with an inner diameter of 1 mm. Then, the hydrogel solution obtained in step one is injected into the sandwich formed by the two silicone tubes. After curing with a 365 nm UV lamp, the inner and outer silicone tubes are removed to obtain a tubular hydrogel layer.

[0094] Step 3:

[0095] A quartz optical fiber is inserted into the tubular hydrogel layer obtained in step two. After curing, a sodium alginate solution (5% by mass) and a calcium chloride solution (0.1 mol·L⁻¹) are used. -1Alternating immersion forms a cladding layer, resulting in a liquid-core fiber optic probe (as shown in Figure 13).

[0096] III. Characterization of Co / PHI materials:

[0097] As shown in Figure 2, Co / PHI exhibits an ultrathin, silk-like sheet structure. However, no aggregates or isolated Co particles appear in the TEM image, indicating that Co does not agglomerate. As shown in Figure 3, further analysis using EDS elemental distribution maps reveals that Co, O, C, and N elements are uniformly distributed throughout the scanning area, indicating a high degree of Co dispersion on PHI.

[0098] As shown in Figure 4, the X-ray diffraction (XRD) pattern of the material shows that the peaks at 8.2° and 28.0° correspond to the (100) and (002) characteristic diffraction peaks of PHI, respectively, indicating that PHI was successfully synthesized. Furthermore, the peak intensity and position of the XRD did not change significantly after the introduction of Co, indicating that the main structure and crystal structure of PHI were not affected.

[0099] As shown in Figure 5, 2180cm -1 The presence of the -C≡N characteristic peak in PHI indicates that polyheptamethrin imide was successfully synthesized, and the introduction of Co did not significantly alter the structure of the main functional groups in PHI.

[0100] IV. Application of cobalt-modified polyheptamethrinimide in the photosensitization of paracetamol using Rhodamine B: Paracetamol was detected using cobalt-modified polyheptamethrinimide in any of the following methods:

[0101] Method 1:

[0102] 1) Solution preparation: Take 0.002 g of RhB red powder and dilute it to 1000 mL of deionized water to prepare a solution of 2 mg·L⁻¹. -1 RhB aqueous solution (pink); place 0.15 g Co / PHI powder in a 100 mL volumetric flask, dilute to volume with deionized water, and sonicate and stir thoroughly to form 1.5 g·L⁻¹. -1 White suspension; take a certain amount of paracetamol powder and add it to a 100mL volumetric flask, add 0.5mL of methanol first and then dilute to volume with deionized water, and sonicate and stir thoroughly to dissolve the paracetamol completely, and then dilute to prepare paracetamol aqueous solutions of different concentrations;

[0103] 2) After mixing cobalt-modified polyheptamethrinimide with Rhodamine B solution, Rhodamine B-cobalt-modified polyheptamethrinimide was obtained. After mixing Rhodamine B-cobalt-modified polyheptamethrinimide with 1 mL of acetaminophen solution of different concentrations, the test solution was obtained. All test solutions were placed in the Pofil multi-channel photocatalytic reactor, stirred and adsorbed for 5 min under no light conditions, and then 532 nm visible light was turned on for 5 min. After irradiation, the solution was filtered using a 22 μm aqueous phase filter membrane. The filtrate was detected using a UV-Vis spectrophotometer to complete the detection of acetaminophen with Rhodamine B-cobalt-modified polyheptamethrinimide.

[0104] Introducing dispersed cobalt onto PHI is expected to improve the detection capability of paracetamol by enhancing its selective adsorption capacity and promoting RhB sensitization efficiency.

[0105] The detection system was prepared according to the above steps using Co / PHI with a Co loading of 3% as the optimal detection material and then subjected to light irradiation. Figure 6 shows the change in the photosensitization degradation concentration of RhB as the irradiation time increases. The dark adsorption experiment of Co / PHI on RhB under no-light conditions was used as a control.

[0106] When paracetamol is added to the system, the paracetamol system can selectively adsorb onto Co / PHI, blocking the photosensitization and decolorization of RhB, thus increasing the absorption spectral intensity of RhB, as shown in Figure 7. The degree of photosensitization and decolorization of RhB by paracetamol is measured by the blocking rate. To indicate, Calculate using formula (1):

[0107] ;

[0108] In the formula, This indicates the blocking rate of RhB photosensitization decolorization after the addition of paracetamol;

[0109] C I This indicates the RhB concentration in the detection system after adding acetaminophen, in mg·L⁻¹. -1 ;

[0110] C represents the concentration of RhB after sensitization and decolorization without acetaminophen, in mg·L⁻¹. -1 ;

[0111] C0 * This indicates the concentration of RhB in the solution after dark adsorption filtration by Co / PHI, in mg·L⁻¹. -1 .

[0112] The results showed that when a concentration of 10 ng·L was introduced into the heat treatment system... -1 ~1mg·L -1Within the range, the logarithm of the RhB blocking rate The logarithm lg[c] of acetaminophen concentration has a linear fit, as shown in Figure 8. The fitted linear equation is as follows: =0.306lg[C 扑热息痛 -0.7833, linear correlation coefficient R 2 The value was 0.99056, and the limit of quantitation was 10 ng·L⁻¹. -1 .

[0113] Other PPCPs (poly(acetylene-containing compounds)) organic pollutants often coexist in real-world environmental systems. To explore the selectivity of the Co / PHI photosensitization detection system for acetaminophen, Figure 9 shows the effect of adding several potential interfering substances to Co / PHI on acetaminophen detection. The results show that in the absence of acetaminophen, other coexisting interfering substances have low blocking rates for RhB, and the system exhibits a decolorized white state, indicating that the photosensitization system has no significant response to other interfering substances. However, when acetaminophen is present in the system, RhB turns pink, demonstrating that the detection system has a significant selective response to acetaminophen. This indicates that environmental interference has a relatively small impact on the detection results of acetaminophen, thus this method achieves excellent selective detection of acetaminophen.

[0114] Method 2 (Fiber Optic Detection Process):

[0115] Solution preparation: Take a 25mL weighing bottle and add 0.2mL of acetaminophen solution of different concentrations, 2mg·L⁻¹. -1 0.9 mL of RhB solution, 1.5 g·L -1 0.9 mL of Co / PHI solution was mixed thoroughly and used as the test solution. 40 μL of the test solution was injected into the core probe using a syringe. The core probe was then connected to the HOURS-532 light source, and the 532 nm single-wavelength light source was turned on for 6 min. The concentration of paracetamol added to the system was continuously increased (40 μg / L). -1 →1mgL -1 The blocking effect of sensitization and decolorization is significantly enhanced. The color comparison is shown in Figure 10. A standard colorimetric card was made according to different concentrations of acetaminophen and their corresponding fiber optic probe colors, as shown in Figure 11.

[0116] As shown in Figures 14-15, cobalt-modified polyheptamethrinimide was mixed evenly with Rhodamine B solution to obtain Rhodamine B-cobalt-modified polyheptamethrinimide; Rhodamine B-cobalt-modified polyheptamethrinimide was mixed evenly with 0.2 mL of acetaminophen solution to obtain the test suspension; the test solution was injected into the liquid-core fiber optic probe using a syringe and then sealed; the fiber optic liquid-core probe was connected to the HOURS-532 light source, and then the 532 nm single-wavelength light source was turned on for 3 min;

[0117] Therefore, by comparing the color of the fiber optic probe obtained from an unknown sample with a standard colorimetric card, a visual semi-quantitative detection of acetaminophen can be achieved. The lowest detectable concentration that can be visually distinguished is 40 μg·L⁻¹. -1 This enables rapid, visual detection of colorless paracetamol.

[0118] On the other hand, the RGB values ​​of the liquid core probe color are identified using mobile phone RGB color recognition software. The specific detection device diagram is shown in Figure 12. The brightness value is calculated based on the RGB values ​​obtained from the mobile phone: [0.299×R + 0.587×G + 0.114×B]. When paracetamol is at 40 μg / L... -1 ~1mgL -1 Within the concentration range, the calculated brightness is proportional to the logarithm lg[C] of the acetaminophen concentration. 扑热息痛 It can be fitted into a linear equation, as shown in Figure 16. The linear equation is: brightness = -33.579lg[C] 扑热息痛 +220.51, linear correlation coefficient R 2 The value is 0.9931, and this method can achieve accurate quantitative detection of concentration.

[0119] V. Innovations of this invention:

[0120] This invention successfully establishes for the first time a portable, visual, and rapid detection system for paracetamol using an RhB-Co / PHI photosensitization system. This system enhances the selective adsorption and enrichment of paracetamol by utilizing the interaction between Co introduced onto PHI and paracetamol, thereby improving the selectivity and sensitivity of paracetamol detection. The use of a liquid-core fiber optic probe integrates detection and signal transmission, making detection more convenient and faster.

Claims

1. A method for preparing cobalt-modified polyheptamethrin imide, characterized in that... The preparation method is carried out according to the following steps: Step S1: Melamine and cyanuric acid are added to deionized water respectively, and stirred at 50~100℃ until completely dissolved to obtain solution A and solution B respectively; at 50~100℃, solution B is added to solution A, and stirred evenly to obtain mixture C; after heating and stirring for 20~40 min, potassium thiocyanate is added, and after heating and stirring for 20~40 min, cobalt nitrate is added, and after heating and stirring for 1.5~3 h, the mixture is cooled after heating and stirring, centrifuged and the supernatant is discarded. The white particles are collected, washed, dried and ground to obtain powder D; Step S2: Under nitrogen protection, powder D obtained in step S1 is placed in a tube furnace, heated to 500~550℃, and calcined at 500~550℃ for 3~5 h; after calcination, it is naturally cooled to room temperature. The sample was calcined once to obtain a sample after the first calcination. The sample was then placed again in a tube furnace and heated to 450–510 °C under air conditions for 1.5–3 hours. After calcination, it was allowed to cool naturally to room temperature to obtain a sample after the second calcination. This sample was then mixed with potassium chloride and lithium chloride, ground, and placed in a tube furnace. Under nitrogen protection, the temperature was raised to 530–570 °C and calcined for 3.5–4.5 hours. After calcination, it was allowed to cool naturally to room temperature to obtain a sample after molten salt calcination. This sample was then added to a nitric acid solution and stirred in a water bath at 60–80 °C for 1–2 hours. After cooling, it was centrifuged, the supernatant was discarded, and the remaining solid was collected, washed, dried, and then dispersed in deionized water to prepare a solution with a concentration of 1.0–3.0 g·L⁻¹. -1 Cobalt-modified polyheptamethine imide.

2. The method for preparing cobalt-modified polyheptamethine imide according to claim 1, characterized in that... The mass ratio of melamine, cyanuric acid and deionized water in step S1 is (8~13) g: (3~5) g: (300~550) mL; the mass ratio of melamine, cyanuric acid, potassium thiocyanate and cobalt nitrate in step S1 is (8~11): (3~5): (0.2~0.3): (0.2~0.3).

3. The method for preparing cobalt-modified polyheptamethine imide according to claim 1, characterized in that... In step S1, the centrifugation speed is 3000~5000 r / min and the centrifugation time is 3~7 min; the washing is done by washing with deionized water and anhydrous ethanol 3~5 times each; the drying temperature is 50~80℃.

4. The method for preparing cobalt-modified polyheptamethine imide according to claim 1, characterized in that... In step S2, nitrogen protection means that the nitrogen gas introduction rate is 120~180 mL / min; in step S2, the temperature is increased to 500~550℃ at a heating rate of 1~3℃ / min; in step S2, the temperature is increased to 450~510℃ at a heating rate of 4~6℃ / min under air conditions; and in step S2, the temperature is increased to 530~570℃ at a heating rate of 4~6℃ / min under nitrogen protection.

5. The method for preparing cobalt-modified polyheptamethine imide according to claim 1, characterized in that... In step S2, the mass ratio of the sample after secondary calcination, potassium chloride, and lithium chloride is (0.3~0.6):(0.4~0.45):(0.3~0.35); the mass ratio of the sample after molten salt calcination to the volume of nitric acid solution in step S2 is (0.5~0.8) g:(50~80) mL, and the concentration of the nitric acid solution is 3~6 mol·L⁻¹. -1 .

6. The method for preparing cobalt-modified polyheptamethine imide according to claim 1, characterized in that... After cooling in step S2, centrifuge at 3000~5000 r / min for 4~6 min; the washing in step S2 is to wash with deionized water and anhydrous ethanol 3~5 times each; the drying temperature is 40~70℃.

7. The application of the cobalt-modified polyheptamethamide prepared by the method according to any one of claims 1-6 in the photosensitization detection of acetaminophen by rhodamine B, characterized in that... Paracetamol was tested using cobalt-modified polyheptamethrinimide in any of the following methods: Method 1: A concentration of 1.0–3.0 g·L⁻¹ was used. -1 Cobalt-modified polyheptamethrinimide with a concentration of 1-8 mg·L -1 After mixing the Rhodamine B solution evenly, Rhodamine B-cobalt modified polyheptamethrin imide is obtained; the volume ratio of the cobalt modified polyheptamethrin imide to the Rhodamine B solution is (0.5~1.0):(0.5~1.0); after mixing the Rhodamine B-cobalt modified polyheptamethrin imide with acetaminophen solution evenly, the test suspension is obtained; the test suspension is placed in a Pofil multi-channel photocatalytic reactor, and stirred and adsorbed for 4~7 min under no light conditions, then 532 nm visible light is turned on, and after irradiation for 3~5 min, it is filtered using a 22μm aqueous phase filter membrane. The filtered filtrate is detected using a UV-Vis spectrophotometer to complete the detection of acetaminophen with Rhodamine B-cobalt modified polyheptamethrin imide; Method 2: 1.0~3.0 g·L -1 Cobalt-modified polyheptamethrinimide with a concentration of 1-8 mg·L -1 After thoroughly mixing the Rhodamine B solution, Rhodamine B-cobalt modified polyheptamethrin imide was obtained; the volume ratio of the cobalt modified polyheptamethrin imide to the Rhodamine B solution was (0.5~1.0):(0.5~1.0); after thoroughly mixing the Rhodamine B-cobalt modified polyheptamethrin imide with paracetamol solution, a test suspension was obtained; the volume ratio of the Rhodamine B solution, cobalt modified polyheptamethrin imide, and paracetamol solution in the Rhodamine B-cobalt modified polyheptamethrin imide was (0.5~1.0):(0.5~1.0):0.2; the test suspension was injected into the liquid-core fiber optic probe using a syringe and sealed, and the liquid-core fiber optic probe was connected to the HOURS-532 light source, and then the 532 was turned on. A single-wavelength light source (nm) was used for 3-5 minutes to detect acetaminophen with rhodamine B-cobalt modified polyheptamethrin imide. The liquid-core fiber optic probe was prepared by the following steps: Step 1: Polyethylene glycol acrylate and 2-hydroxy-2-methyl-1-phenyl-1-propanone were added to deionized water and ultrasonically mixed to obtain a hydrogel solution. Step 2: A silicone tube with an inner diameter of 3 mm was placed over a silicone tube with an inner diameter of 1 mm. The hydrogel solution obtained in Step 1 was then injected into the sandwich formed by the two silicone tubes. After curing with a 365 nm UV lamp, the inner and outer silicone tubes were removed to obtain a tubular hydrogel layer. Step 3: A quartz optical fiber was inserted into the tubular hydrogel layer obtained in Step 2. After curing, the fiber was alternately soaked in sodium alginate solution and calcium chloride solution to obtain the liquid-core fiber optic probe.

8. The application of the cobalt-modified polyheptamethrinimide according to claim 7 in the photosensitization detection of acetaminophen by Rhodamine B, characterized in that... The volume of the Rhodamine B aqueous solution is 5-8 mL, and the concentration is 1-3 mg·L⁻¹. -1 The cobalt-modified polyheptamethrin imide suspension has a volume of 2-4 mL and a concentration of 1-2.5 g·L⁻¹. -1 The volume of the paracetamol aqueous solution is 0.5~2mL.

9. The application of the cobalt-modified polyheptamethrinimide according to claim 7 in the photosensitization detection of acetaminophen by Rhodamine B, characterized in that... In step one, the volume ratio of polyethylene glycol acrylate, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and deionized water is (2~4):(0.3~0.5):(4~6); the ultrasonication time in step one is 20~50 min; the mass fraction of sodium alginate in the sodium alginate solution in step three is 1~5%, and the concentration of the calcium chloride solution is 0.05~2 mol·L⁻¹. -1 .

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