Surface coating materials, solid-phase microextraction probes, their preparation methods and applications

Abstract

This invention discloses a surface coating material, a solid-phase microextraction probe, its preparation method, and its application, relating to the field of veterinary drug detection technology. The probe comprises a metal rod and a coating applied to the outer surface of the metal rod. The surface coating material is prepared by electrospinning a mixture of SBA-15 material, polyacrylonitrile, and N,N-dimethylformamide. The ratio of SBA-15 material, polyacrylonitrile, and N,N-dimethylformamide is 100mg–300mg: 100mg–300mg: 2mL–4mL. This invention addresses the problems of inconvenient equipment portability and long detection times in existing technologies.

Description

Technical Field

[0001] This invention belongs to the field of veterinary drug detection technology, specifically relating to a surface coating material, a solid-phase microextraction probe, its preparation method, and its application. Background Technology

[0002] Veterinary drugs are indispensable for disease prevention in modern animal husbandry, but they may leave residues. Therefore, developing rapid, effective and accurate veterinary drug testing methods is crucial for ensuring food safety, and on-site analysis technology is becoming increasingly important.

[0003] Solid-phase microextraction (SPME) is a novel sample preparation technique suitable for both laboratory and field applications. It involves coating an adsorbent material onto the surface of a bare metal rod using electrospinning to create a solid-phase microextraction probe. This probe is then exposed to the sample system for extraction, enrichment, injection, and desorption of the analyte. This technique simplifies operation, reduces reagent consumption, and improves analytical efficiency. Furthermore, it can be coupled with liquid chromatography and gas chromatography-mass spectrometry (GC-MS) for quantitative analysis. The coating of the solid-phase microextraction probe is the core of SPME; different coating materials have different effects on target analytes with different properties.

[0004] Popular adsorbent materials include mesoporous silica materials, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs). Mesoporous silica materials possess excellent properties, including porosity, ordered pore channels, good stability, and broad functionalization capabilities. MOFs are coordination polymers, characterized by porous structures formed by the coupling of transition ion clusters or metal ions with organic ligands through coordination bonds. On the other hand, COFs represent highly ordered crystalline porous organic materials composed of light elements linked by reversible covalent bonds. These materials are renowned for their remarkable texture properties and excellent stability, making them widely used in various adsorption applications.

[0005] Portable mass spectrometers (PMS) offer rapid, sensitive, and on-site detection capabilities, overcoming the limitations of large instruments. PMS is a promising alternative to chromatographic separation for multiplexing. A portable mass spectrometer has three main subsystems: an ionization source, an analyzer, and a detector assembly. The ionization source converts the substance to be measured into charged particles, which are then separated by the mass spectrometer based on the mass-to-charge ratio of each target. The detector assembly converts the ion intensity into an electrical signal for digitization and readout via a digital acquisition system. The ionization source in a portable mass spectrometer should be simple in structure and low in power consumption. Commonly used ionization sources in PMS include electron impact ionization (EI), ambient ionization (AI), dielectric plug discharge ionization (DBDI), and electrospray ionization (ESI). Recently, ESI-based PMS systems have shown great potential for multiplexing and on-site applications.

[0006] Therefore, developing a coating material with good adsorption properties for veterinary drugs is crucial for improving the accuracy and efficiency of veterinary drug residue analysis. However, existing coating materials cannot effectively adsorb veterinary drug residues, resulting in poor sensitivity and specificity, and consequently, poor reliability of analytical results. Summary of the Invention

[0007] To address the above problems, this invention provides a surface coating material, a solid-phase microextraction probe, its preparation method, and its application, in order to improve upon the inconvenience of carrying out existing equipment and the long detection time.

[0008] This invention is achieved through the following technical solution:

[0009] A surface coating material for a solid-phase microextraction probe is prepared by electrospinning after mixing and stirring SBA-15 material, polyacrylonitrile and N,N-dimethylformamide.

[0010] The ratio of the SBA-15 material, polyacrylonitrile, and N,N-dimethylformamide is 100mg-300mg: 100mg-300mg: 2mL-4mL.

[0011] Preferably, the SBA-15 material is prepared by the following method:

[0012] S1: Add hydrochloric acid solution to the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and mix in a water bath to completely dissolve the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer.

[0013] S2: Add tetraethyl silicate to a solution of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, mix in a water bath, and then carry out a hydrothermal synthesis reaction;

[0014] S3: After the reaction is complete, filter to obtain a white precipitate, wash and dry for 8 hours;

[0015] S4: Calcine the material after it has been dried overnight to synthesize SBA-15.

[0016] Preferably, the method for preparing the surface coating material of the solid-phase microextraction probe includes:

[0017] S(1): N,N-dimethylformamide is dissolved in polyacrylonitrile;

[0018] S(2): Add SBA-15 material to the mixture of polyacrylonitrile and N,N-dimethylformamide and stir for 2 to 3 hours to obtain an electrospinning coating solution containing SBA-15, which is the surface coating material.

[0019] Preferably, the probe comprises a metal rod and a coating applied to the outer surface of the metal rod, wherein the coating is the electrospinning coating liquid.

[0020] Preferably, the solid-phase microextraction probe is prepared using a method comprising:

[0021] The surface of the metal rod was cleaned with water and ethanol to remove impurities and then dried for later use. The electrospinning coating solution was then coated onto the dried metal rod by electrospinning to form a coating. The metal rod was then immersed in an ethanol solution and finally dried in a drying oven to obtain a solid-phase microextraction probe.

[0022] Preferably, the coating has a thickness of 265 μm and a length of 1 cm.

[0023] Preferably, the diameter of the metal rod is 980 μm.

[0024] Preferably, the veterinary drug being tested is one or more of sulfadiazine, thiabendazole, amantadine, ractopamine, and clenbuterol.

[0025] Preferably, the veterinary drug detection conditions include: performing analysis using a portable mass spectrometer equipped with an electrospray ionization source and a hyperbolic ion trap in positive ion mode, maintaining the inlet temperature at 200°C, and setting the voltage of the electrospray ionization source to 2kV. The sheath gas and auxiliary flow rates are both set to 2.5 L·min. -1 .

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The surface coating of the solid-phase microextraction probe of this invention is prepared from mesoporous silica material SBA-15, polyacrylonitrile, and N,N-dimethylformamide. Mesoporous silica materials exhibit high extraction efficiency due to their ordered pore channels, good stability, and broad functionalization capabilities. The electrospinning method offers advantages such as uniform coating, cost-effectiveness, reusability, and good stability. The prepared nanofibers possess high specific surface area and rapid mass transfer kinetics, significantly increasing their active adsorption sites. The addition of a portable mass spectrometer further enhances the mechanical and thermal stability of the surface coating, making the prepared solid-phase microextraction probe less prone to damage and enabling better coupling with a portable mass spectrometer.

[0028] Solid-phase microextraction probes can withstand up to 50 extraction and desorption cycles and are suitable for detection in milk and chicken. The detection limit is 7 μg·L⁻¹. -1 ~28μg·L -1 The limit of quantitation is 22 μg·L⁻¹. -1 ~86μg·L -1 It has good sensitivity and specificity, and the analytical results are highly reliable.

[0029] The solid-phase microextraction probe is simple to prepare and inexpensive. Compared with commercially available probes, the solid-phase microextraction probe prepared in this invention has better extraction efficiency for veterinary drugs. Combined with a portable mass spectrometer, it can perform quantitative analysis of sulfadiazine, thiabendazole, amantadine, ractopamine and clenbuterol. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 A schematic diagram illustrating the preparation method of solid-phase microextraction probes and the principle of solid-phase microextraction combined with portable mass spectrometry for the detection of veterinary drugs;

[0032] Figure 2 Mass spectra of five veterinary drugs detected by a portable mass spectrometer;

[0033] Figure 2 In the image, (a) is the mass spectrum for the detection of amantadine; (b) is the mass spectrum for the detection of thiabendazole; (c) is the mass spectrum for the detection of clenbuterol; (d) is the mass spectrum for the detection of sulfadiazine; and (e) is the mass spectrum for the detection of ractopamine.

[0034] Figure 3The graph shows a comparison of coating materials and an absolute recovery graph of the SBA-15 solid-phase microextraction probe for five veterinary drugs and two competing compounds.

[0035] Figure 3 In the table, (a) compares the adsorbed coating materials: 1 represents UiO-66-NH2-50%, 2 represents MCM-41, 3 represents 4-meso-UiO-66, 4 represents SBA-15, 5 represents SBA-16, 6 represents HCl-meso-UiO-66, 7 represents Meso-UiO-66, and 8 represents polyacrylonitrile; (b) shows the absolute recoveries of the SBA-15 solid-phase microextraction probe for five veterinary drugs and two competing compounds. The mixed solution contained 3 μg·mL⁻¹ -1 Amantadine, thiabendazole, sulfadiazine, clenbuterol, and ractopamine, and 300 μg·mL -1 Bisacodyl and metronidazole;

[0036] Figure 4 Figure showing the optimization of electrospinning conditions for solid-phase microextraction probes;

[0037] Figure 4 In the table, (a) represents the material ratio in the electrospinning coating solution, where 1 represents 100 mg polyacrylonitrile + 100 mg SBA-15 + 2 mL N,N-dimethylformamide, 2 represents 100 mg polyacrylonitrile + 200 mg SBA-15 + 3 mL N,N-dimethylformamide, 3 represents 100 mg polyacrylonitrile + 300 mg SBA-15 + 4 mL N,N-dimethylformamide, 4 represents 100 mg polyacrylonitrile + 100 mg SBA-15 + 3 mL N,N-dimethylformamide, 5 represents 100 mg polyacrylonitrile + 200 mg SBA-15 + 4 mL N,N-dimethylformamide, and 6 represents 300 mg polyacrylonitrile + 100 mg SBA-15 + 4 mL N,N-dimethylformamide; and (b) represents the electrospinning time.

[0038] Figure 5 Scanning electron microscope images of the SBA-15 solid-phase microextraction probe at different spinning times;

[0039] Figure 5Images (a), (b), (c), (d), (e), and (f) are scanning electron microscope (SEM) images at 30x for a metal rod with a diameter of 0.98 mm after electrospinning for 20 min, 30 min, 40 min, 50 min, and 60 min, respectively. Images (g), (h), (i), and (j) are scanning electron microscope (SEM) images at 50x for electrospinning for 20 min, 30 min, 40 min, 50 min, and 60 min, respectively. Scanning electron microscope (SEM) images: (k)(i)(m)(m)(n)(o) are the scanning electron microscope (SEM) images of electrospinning at 10000x for 20 min, 30 min, 40 min, 50 min, and 60 min, respectively; (p)(q)(r)(s)(t) are the scanning electron microscope (SEM) images of electrospinning at 30000x for 20 min, 30 min, 40 min, 50 min, and 60 min, respectively.

[0040] Figure 6 The SBA-15 coating was prepared by electrospinning for 40 min. (a)(b)(c)(d) are scanning electron microscope images at 30x, 50x, 10000x and 30000x, respectively.

[0041] Figure 7 The optimized diagram of the SBA-15 solid-phase microextraction probe program;

[0042] Figure 7 In the table, (a) is the sample volume; (b) is the rotation speed; (c) is the sodium chloride concentration; (d) is the extraction temperature; (e) is the extraction time; (f) is the desorption solvent: in (f) 1 represents acetonitrile; 2 represents acetone; 3 represents methanol; 4 represents acetonitrile:water = 9:1 (v / v); 5 represents acetonitrile:water = 7:3 (v / v); 6 represents acetonitrile:water = 1:9 (v / v); and (g) is the desorption time.

[0043] Figure 8 The results are for testing the PDMS-solid-phase microextraction probe under optimal extraction and desorption conditions.

[0044] Figure 8 In the table, (a) represents the extraction time, (b) represents the desorption solvent, 1 represents methanol:water = 7:3, 2 represents acetonitrile:water = 7:3, 3 represents methanol:water = 9:1, 4 represents acetone:water = 7:3 and (c) represents the desorption time;

[0045] Figure 9 The test results of the Polyacrylate-solid-phase microextraction probe under optimal extraction and desorption conditions are as follows:

[0046] Figure 9In the table, (a) represents the extraction time, (b) represents the desorption solvent, 1 represents methanol:water = 7:3, 2 represents acetonitrile:water = 7:3, 3 represents methanol:water = 9:1, 4 represents acetone:water = 7:3 and (c) represents the desorption time;

[0047] Figure 10 The results are for the Carbon WR / PDMS solid-phase microextraction probe under optimal extraction and desorption conditions.

[0048] Figure 10 In the table, (a) represents the extraction time, (b) represents the desorption solvent, 1 represents methanol:water = 7:3, 2 represents acetonitrile:water = 7:3, 3 represents methanol:water = 9:1, 4 represents acetone:water = 7:3 and (c) represents the desorption time;

[0049] Figure 11 The test results of the DVB / Carbon WR / PDMS-solid phase microextraction probe under optimal extraction and desorption conditions;

[0050] Figure 11 In the table, (a) represents the extraction time, (b) represents the desorption solvent, 1 represents methanol:water = 7:3, 2 represents acetonitrile:water = 7:3, 3 represents methanol:water = 9:1, 4 represents acetone:water = 7:3 and (c) represents the desorption time;

[0051] Figure 12 The test results of the DVB / PDMS-solid phase microextraction probe under optimal extraction and desorption conditions;

[0052] Figure 12 In the table, (a) represents the extraction time, (b) represents the desorption solvent, 1 represents methanol:water = 7:3, 2 represents acetonitrile:water = 7:3, 3 represents methanol:water = 9:1, 4 represents acetone:water = 7:3 and (c) represents the desorption time;

[0053] Figure 13 A comparison of the extraction efficiency of the SBA-15 solid-phase microextraction probe and a commercial solid-phase microextraction probe under optimal conditions, and a comparison of the extraction performance of the SBA-15 solid-phase microextraction probe and the DVB / PDM solid-phase microextraction probe in milk.

[0054] Figure 13In the table, (a) compares the extraction efficiency of the SBA-15 solid-phase microextraction probe and a commercial solid-phase microextraction probe under optimal conditions; 1 represents the SBA-15 solid-phase microextraction probe; 2 represents the DVB / Carbon WR / PDMS solid-phase microextraction probe; 3 represents the Polyacrylate solid-phase microextraction probe; 4 represents the DVB / PDMS solid-phase microextraction probe; 5 represents the Carbon WR / PDMS solid-phase microextraction probe; 6 represents the PDMS solid-phase microextraction probe; (b) compares the extraction performance of the SBA-15 solid-phase microextraction probe and the DVB / PDMS solid-phase microextraction probe in milk.

[0055] Figure 14 Structural features of the SBA-15 solid-phase microextraction probe before and after 50 extractions and desorptions;

[0056] Figure 14 In the image, (a) shows the SBA-15 solid-phase microextraction probe after 50 cycles; (c) shows the SBA-15 solid-phase microextraction probe after 50 cycles; (b) shows the SBA-15 solid-phase microextraction probe at 10000x; (d) shows the SBA-15 solid-phase microextraction probe after 50 cycles at 10000x; (e) shows the new SBA-15 solid-phase microextraction probe and a macroscopic image of the SBA-15 solid-phase microextraction probe; and (f) shows the reusability of the SBA-15 solid-phase microextraction probe.

[0057] Figure 15 The residual effect experiment of SBA-15 solid-phase microextraction probe. Detailed Implementation

[0058] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0060] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0061] (1) Experimental reagents and equipment

[0062] N,N-Dimethylformamide (DMF), polyacrylonitrile (PAN), adamantane, ethanol, ammonium hydroxide, tetraethyl silicate (TEOS), hexadecyltrimethylammonium bromide (CTAB), zirconium chloride (ZrCl4), terephthalic acid (H2BDC), 4-pentylbenzoic acid, 2-aminoterephthalic acid (NH2-BDC), and acetic acid were purchased from Maclean's in Shanghai, China. Thiabendazole and sulfadiazine were purchased from Yuanye in Shanghai, China. Clenbuterol was from TM Standard in Changzhou, China, and ractopamine was from Anpu in Shanghai, China. Polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123), polyoxyethylene polyoxypropylene ether triblock copolymer (F127), SPME arrow, and bare SPME arrow were all from Merck in Shanghai, China. Hydrochloric acid was purchased from headspace vials from Luoyang Haohua Chemical Reagent Co., Ltd., and polytetrafluoroethylene / silicone diaphragm screw caps were purchased from Merck in Shanghai, China.

[0063] Example 1

[0064] This embodiment relates to a method for preparing a surface coating material for a solid-phase microextraction probe, the specific method of which is as follows:

[0065] (1) Synthesis of SBA-15 material: Take 6.4 g of P123 into a three-necked flask, add 200 mL of 2 mol·L⁻¹ ... -1 A hydrochloric acid solution was prepared and stirred thoroughly in a 40°C water bath until P123 was completely dissolved. Then, 13.6 mL of tetraethyl orthosilicate was added dropwise, and the mixture was stirred thoroughly in a 40°C water bath for 20 hours. The resulting white dispersion was then poured into a polytetrafluoroethylene container, which was placed in a high-pressure reactor and then in a muffle furnace. The mixture was subjected to hydrothermal synthesis at 100°C for 24 hours. After the reaction was complete, the solution was filtered to obtain a white precipitate, which was washed with deionized water and dried at 70°C for 8 hours. The dried material was then placed in a crucible and calcined at 550°C for 6 hours in a muffle furnace to remove the template, thus synthesizing SBA-15.

[0066] (2) Polyacrylonitrile and N,N-dimethylformamide were mixed and stirred with magnetic force to completely dissolve the polyacrylonitrile and mix evenly with the N,N-dimethylformamide. Then, SBA-15 material was added to the mixture of polyacrylonitrile and N,N-dimethylformamide and stirred for 2 hours to obtain an electrospinning coating solution containing SBA-15, which is the surface coating material. The ratio of SBA-15 material, polyacrylonitrile and N,N-dimethylformamide in the electrospinning coating solution is 100mg:200mg:3mL.

[0067] Comparative Example 1

[0068] This embodiment relates to a method for preparing a surface coating material for a solid-phase microextraction probe, the specific method of which is as follows:

[0069] (1) Synthesis of MCM-41 material: 1.25 g of hexadecyltrimethylammonium bromide was dissolved in 490 mL of 14 wt% NH4OH and stirred for 5 min to ensure complete dissolution. Then, 10 mL of tetraethyl silicate was slowly added to the solution, and a white precipitate gradually appeared. The mixture was stirred at room temperature for 2 h. The precipitate was then filtered, dried, and finally calcined in air at 550 °C for 6 h to remove the template.

[0070] (2) Polyacrylonitrile and N,N-dimethylformamide were mixed and magnetically stirred to ensure complete dissolution of the polyacrylonitrile and uniform mixing with the N,N-dimethylformamide. Then, MCM-41 material was added to the mixture of polyacrylonitrile and N,N-dimethylformamide and stirred for 2 hours to obtain an electrospinning coating solution containing MCM-41 material, which is the surface coating material. The ratio of MCM-41 material, polyacrylonitrile, and N,N-dimethylformamide in the electrospinning coating solution was 100 mg: 200 mg: 3 mL.

[0071] Comparative Example 2

[0072] This embodiment relates to a method for preparing a surface coating material for a solid-phase microextraction probe, the specific method of which is as follows:

[0073] (1) Synthesis of SBA-16 material: Take 6.66g of F127 into a three-necked flask, add 200mL of 2mol·L⁻¹ ... -1 The hydrochloric acid solution was stirred thoroughly in a 35°C water bath until F127 was completely dissolved. Then, 25 mL of tetraethyl orthosilicate was added dropwise, and the mixture was stirred thoroughly in a 35°C water bath for 20 hours. The resulting white dispersion was then poured into a polytetrafluoroethylene container, which was placed in a high-pressure reactor and then in a muffle furnace. The mixture was subjected to hydrothermal synthesis at 100°C for 24 hours. After the reaction was complete, the solution was filtered to obtain a white precipitate, which was washed with deionized water and dried at 70°C for 8 hours. The dried material was then placed in a crucible and calcined at 550°C for 6 hours in a muffle furnace to remove the template.

[0074] (2) Polyacrylonitrile and N,N-dimethylformamide were mixed and magnetically stirred to ensure complete dissolution of the polyacrylonitrile and uniform mixing with the N,N-dimethylformamide. Then, SBA-16 material was added to the mixture of polyacrylonitrile and N,N-dimethylformamide and stirred for 2 hours to obtain an electrospinning coating solution containing SBA-16 material, which is the surface coating material. The ratio of SBA-16 material, polyacrylonitrile, and N,N-dimethylformamide in the electrospinning coating solution was 100 mg: 200 mg: 3 mL.

[0075] Comparative Example 3

[0076] This embodiment relates to a method for preparing a surface coating material for a solid-phase microextraction probe, the specific method of which is as follows:

[0077] This comparative example relates to the preparation method of solid-phase microextraction probes made of UiO-66 series materials. The UiO-66 series materials include UiO-66-NH2-50%, Meso-UiO-66, HCl-meso-UiO-66, and 4-meso-UiO-66. Taking UiO-66-NH2-50% as an example, the specific method is as follows:

[0078] (1) Synthesis of UiO-66-NH2-50% material: 320 mg zirconium chloride, 125 mg 2-aminoterephthalic acid, 125 mg terephthalic acid, 9.864 g acetic acid, and 270 mg hydrochloric acid were dispersed in 50 mL of N,N-dimethylformamide. The mixture was then reacted at 120 °C for 24 h. The solid product was washed five times each with N,N-dimethylformamide and ethanol. Finally, UiO-66-NH2-50% was vacuum dried at 150 °C for 12 h; a sample containing 100 mg UiO-66-NH2-50% was heat-treated at 350 °C for 2 h. After cooling to room temperature, the new material was vacuum-dried at 150℃ for 12 h to obtain meso-UiO-66. 100 mg of meso-UiO-66 and 0.2 mL of hydrochloric acid were mixed into 20 mL of N,N-dimethylformamide, heated at 50℃, and stirred for 12 h. The solid product was washed five times each with N,N-dimethylformamide and ethanol. After centrifugation, the new material was vacuum-dried at 150℃ for 12 h and named HCl-meso-UiO-66. 45 mg of HCl-meso-UiO-66, 60 mg of 4-n-pentylbenzoic acid, and 3 mL of LDMF were added to a glass bottle, capped, and stirred at 80℃ for 24 h. The solid product was washed five times each with N,N-dimethylformamide and ethanol, centrifuged, and the new material was vacuum-dried at 150℃ for 12 h and named 4-meso-UiO-66.

[0079] (2) Polyacrylonitrile and N,N-dimethylformamide were mixed and magnetically stirred to completely dissolve the polyacrylonitrile and mix it evenly with the N,N-dimethylformamide. Then, UiO-66-NH2-50% material was added to the mixture of polyacrylonitrile and N,N-dimethylformamide and stirred for 2 hours to obtain an electrospinning coating solution containing UiO-66-NH2-50% material, which is the surface coating material. The ratio of UiO-66-NH2-50% material, polyacrylonitrile and N,N-dimethylformamide in the electrospinning coating solution is 100mg:200mg:3mL.

[0080] The extraction efficiency of surface coating materials prepared from SBA-15, SBA-16, MCM-41, UiO-66-NH2-50%, Meso-UiO-66, HCl-meso-UiO-66, and 4-meso-UiO-66 in Examples 1 and Comparative Examples 1-3, respectively, for five veterinary drugs, namely sulfadiazine, thiabendazole, amantadine, ractopamine, and clenbuterol, was evaluated. Among these materials, the surface coating material prepared from SBA-15 exhibited the highest adsorption capacity for all analytes, such as... Figure 3 As shown in (a) above. Further selectivity tests were performed on the surface coating material prepared with SBA-15 in the presence of two other antibiotics, bisacodyl and metronidazole, and the results showed that despite the high concentrations of these competing compounds, there was no significant effect on the adsorption of the five target veterinary drugs. Figure 3 As shown in (b) above. These results demonstrate that the surface coating material prepared by SBA-15 exhibits superior extraction capability and selectivity even in the presence of interfering substances. Therefore, the electrospinning coating solution prepared by SBA-15 was used as the surface coating material for the solid-phase microextraction probe.

[0081] Example 2

[0082] This embodiment relates to a method for preparing a solid-phase microextraction probe, the specific method of which is as follows:

[0083] Clean the surface of the metal rod repeatedly with water and ethanol to remove oil stains and impurities, then dry it for later use. The metal rod has a diameter of 0.98 mm. Figure 5 As shown in (a) above. The cleaned metal rod is fixed to the motor, and the surface coating material is applied to the dried metal rod using a handheld electrospinning machine to form a coating. The electrospinning voltage is 14 kV, and the working rate is 17 μL·min. -1 The distance from the syringe needle tip to the metal rod tip was 15 cm, and the inner diameter of the electrospinning apparatus was 0.6 mm. The electrospinning time was 40 min. After electrospinning, the final coating thickness of the metal rod was 265 μm, and the surface coating length was 1 cm. The metal rod was immersed in an ethanol solution for 1 h to promote the solvent exchange reaction. Finally, the solid-phase microextraction probe was dried in an 80℃ drying oven for 12 h. The schematic diagram of the solid-phase microextraction probe preparation method is shown below. Figure 1 As shown.

[0084] Example 3

[0085] This embodiment involves the effect of SBA-15 surface coating material on the extraction of five analytes by a solid-phase microextraction probe under different electrospinning conditions, as detailed below:

[0086] like Figure 4 As shown in (a), adsorption performance was observed in the ratio of SBA-15 material, polyacrylonitrile, and N,N-dimethylformamide at 100-300 mg: 100-300 mg: 2 mL-4 mL, with optimal adsorption performance observed when 100 mg of polyacrylonitrile, 200 mg of SBA-15, and 3 mL of N,N-dimethylformamide were mixed. This composition may contribute to the formation of more effective adsorption sites on the SBA-15 coating. Conversely, when the added weights of PAN and SBA-15 were too low, the SBA-15 coating on the metal substrate became weak, attributed to the low viscosity of the electrospinning coating solution. Conversely, excessive addition of SBA-15 hindered diffusion pathways and reduced the effective specific surface area. Therefore, the composition of 100 mg of polyacrylonitrile and 200 mg of SBA-15 in 3 mL of N,N-dimethylformamide was selected as the optimal electrospinning coating solution ratio for manufacturing solid-phase microextraction probes.

[0087] like Figure 5 As shown, with the electrospinning time increasing from 20 min to 60 min, the thickness of the SBA-15 coating increased from 135 μm to 300 μm. Correspondingly, the extraction capacity of the SBA-15 coating for the five veterinary drugs was significantly improved. However, further extending the electrospinning time to over 40 min did not significantly improve the extraction capacity, possibly because the excessively thick coating hindered the diffusion pathway and slowed down the adsorption kinetics. Therefore, we selected an electrospinning time of 40 min to fabricate the solid-phase microextraction probe, such as... Figure 4 As shown in (b) above. Scanning electron microscope images of the solid-phase microextraction probe at different magnifications after 40 min are shown below. Figure 6 As shown, the surface coating material prepared by SBA-15 is uniformly coated on the bare solid-phase microextraction probe.

[0088] Example 4

[0089] The specific method for determining the solid-phase microextraction probe program is as follows:

[0090] (1) The effect of different sample solutions on the results

[0091] First, the effect of sample volume on the extraction efficiency of the SBA-15 surface coating material was investigated. Due to the strong turbulence effect and rapid analyte diffusion, theoretically a smaller sample volume should improve extraction efficiency. However, the extraction efficiencies observed at sample volumes of 5 mL and 10 mL were comparable. Figure 7 As shown in (a) above. However, considering the protective effect on the coating, a sample volume of 10 mL was chosen for subsequent experiments.

[0092] (2) Effect of different sodium chloride concentrations on the results

[0093] As the sodium chloride concentration increased from 0% to 40%, the extraction efficiency of the SBA-15 surface coating material decreased for all analytes, such as... Figure 7 As shown in (c) in the figure. This is because the higher the salt concentration, the greater the solubility of the target analyte in water, thereby reducing the distribution constant between the coating and the aqueous phase. Therefore, no salt was added to the extract in subsequent studies.

[0094] (3) Effect of different stirring speeds on the results

[0095] Stirring speed has a significant impact on extraction efficiency. As the stirring speed increases from 0 r / min... -1 Increase to 750 r·min -1 SBA-15 surface coating material improved the extraction efficiency of five veterinary drugs, such as... Figure 7 As shown in (b) of the figure. However, further increases in stirring speed lead to eddy currents, resulting in incomplete coating immersion and reduced extraction efficiency. Therefore, in subsequent experiments, the optimal stirring speed was determined to be 750 r·min. -1 .

[0096] (4) Effect of different extraction temperatures on the results

[0097] The effect of adsorption temperature on the extraction efficiency of the SBA-15 surface coating material was studied. Figure 7 As shown in (d), the extraction efficiency decreases with increasing temperature. This is because the exothermic nature of the adsorption process causes stronger thermal agitation of the analyte, followed by desorption, thus reducing the extraction efficiency. Therefore, the optimal extraction temperature is set at 25°C.

[0098] (5) Effect of different extraction times on the results

[0099] SPME is an equilibrium-driven process, typically reaching adsorption equilibrium within a certain timeframe. For example... Figure 7 As shown in (e), equilibrium was reached after 15 minutes of adsorption, and no further adsorption was observed as the adsorption time increased.

[0100] (6) The influence of different desorption parameters on the results

[0101] like Figure 7 As shown in (f), acetonitrile exhibited the highest desorption efficiency among the tested desorption solvents because it is less polar than methanol and, as a polar aprotic solvent, has higher elution efficiency. Therefore, acetonitrile was selected as the optimal desorption solvent. Subsequent optimization of the desorption time showed, as... Figure 7 As shown in (g), 30 minutes is sufficient to achieve the maximum desorption of the target analyte.

[0102] Example 5

[0103] This embodiment relates to the reusability test of a solid-phase microextraction probe coated with SBA-15 surface coating material. The SBA-15 surface coating material-coated solid-phase microextraction probe is abbreviated as SBA-15-solid-phase microextraction probe, and the specific method is as follows:

[0104] like Figure 14 As shown, the structural characteristics of the SBA-15 solid-phase microextraction probe before and after 50 extraction and desorption cycles are described. The metal rod of the solid-phase microextraction probe has a uniform SBA-15 coating. After 50 adsorption and desorption cycles, the changes in its appearance or internal structure are negligible. Furthermore, the extraction efficiency trends of clenbuterol and amantadine over 50 cycles were also verified, indicating a slight decrease in extraction efficiency by the 50th cycle, but the solid-phase microextraction probe can still effectively extract the target analytes, demonstrating commendable reusability.

[0105] Further reproducibility tests were conducted, including intra-batch and inter-batch reproducibility tests. Within the same batch, the relative standard deviation (RSD) of reproducibility remained below 17.0%, indicating stable performance of the solid-phase microextraction probe. Similarly, the relative standard deviation of reproducibility between different batches also remained below 20.0%, indicating equally good reproducibility between different batches.

[0106] The residual rate was quantified by comparing the mass of the target compound in three desorption cycles with the mass desorbed in the first 30 minutes. Figure 15 As shown, the results indicate that 200 μL of acetonitrile for 30 min is sufficient to desorb most of the analytes on the SBA-15 solid-phase microextraction probe.

[0107] Example 6

[0108] This embodiment involves the extraction performance testing of the SBA-15 solid-phase microextraction probe, and the specific method is as follows:

[0109] Under optimal extraction and desorption conditions, the extraction efficiency of the SBA-15 solid-phase microextraction probe was further compared with that of commercially available solid-phase microextraction probes coated with carbon nanotubes (Carbon WR) and polydimethylsiloxane (PDMS), divinylbenzene (DVB) and polydimethylsiloxane (PDMS), polydimethylsiloxane (PDMS), divinylbenzene (DVB) and carbon nanotubes (Carbon WR) and polydimethylsiloxane (PDMS), and polyacrylate. (See [link to article]) Figures 8 to 12 , Figure 8 The results are for testing the PDMS-solid-phase microextraction probe under optimal extraction and desorption conditions. Figure 9 The results are for testing the polyacrylate-solid-phase microextraction probe under optimal extraction and desorption conditions. Figure 10The results are for the CarbonWR / PDMS-solid phase microextraction probe under optimal extraction and desorption conditions. Figure 11 The test results of the DVB / CarbonWR / PDMS-solid phase microextraction probe under optimal extraction and desorption conditions are as follows. Figure 12 These are the test results for the DVB / PDMS-solid phase microextraction probe under optimal extraction and desorption conditions. Figure 13 As shown in (a), the DVB and PDMS solid-phase microextraction probes exhibited the highest extraction capabilities for the five analytes among the five commercially available solid-phase microextraction probes. However, except for thiabendazole, the SBA-15 solid-phase microextraction probe demonstrated significantly higher extraction efficiency than the DVB and PDMS probes. Furthermore, the applicability of the SBA-15, DVB, and PDMS solid-phase microextraction probes for extracting five analytes from milk samples was compared. Figure 13 As shown in (b), the SBA-15 solid-phase microextraction probe exhibits higher extraction efficiency and selectivity for amantadine, clenbuterol, sulfadiazine, and ractopamine. The DVB and PDMS solid-phase microextraction probes show slightly higher extraction efficiency for thiabendazole. In summary, compared to commercially available solid-phase microextraction probes, the SBA-15 solid-phase microextraction probe demonstrates superior extraction efficiency and selectivity for these five veterinary drugs. This is attributed to the high chemical affinity of SBA-15 for the analytes, the abundant binding sites of SBA-15, and the high permeability of PAN nanofibers.

[0110] Example 7

[0111] This embodiment involves the method verification of the SBA-15 solid-phase microextraction probe, and the specific method is as follows:

[0112] Matrix effects (ME) are unavoidable in mass spectrometry analysis and negatively impact the accuracy and precision of the method. Matrix effects are assessed by comparing the slopes of calibration curves for the actual sample K1 and the standard solution K2. Matrix effect = (1-K1 / K2)×100%. Matrix effect values ​​between -20% and 20% indicate a slight signal suppression or enhancement effect, between -50% and 50% indicate a moderate effect, and below -50% or above 50% indicate a strong effect. The matrix effects for the five analytes ranged from 75.3% to 99.9%, indicating a significant matrix effect in milk and chicken samples after pretreatment with the SBA-15 solid-phase microextraction probe. Therefore, matrix-matched calibration curves were used to compensate for the observed matrix effects during quantification. As shown in Table 1, the linear range, correlation coefficient R, limit of quantitation (LOQ), limit of detection (LOD), and repeatability of the SBA-15 solid-phase microextraction probe-portable mass spectrometry method obtained using the matrix-matched calibration strategy were evaluated. The correlation coefficients (R) of the solid-phase microextraction probe-portable mass spectrometry method for all five target analytes were greater than 0.995. The limits of detection (LODs) calculated based on signal-to-noise ratios of 3 and 10 were 7 μg·L⁻¹. -1 ~28μg·L -1 and 22 μg·L -1 ~86μg·L -1 The intraday and interday relative standard deviations were 3.2% to 10.3% and 8.5% to 12.1%, respectively, indicating that the method has good precision.

[0113] Table 1 Results of matrix matching calibration strategy

[0114]

[0115] Example 8

[0116] This embodiment relates to the feasibility test of a portable mass spectrometer (PMS), and the specific method is as follows:

[0117] The portable mass spectrometry detection conditions are as follows:

[0118] This study used ultrapure water with a resistivity of 18.25 Mcm, sourced from an ultrapure water system purchased from Chengdu Yinghang Water Treatment Equipment Co., Ltd. 30 mg of each of the five target compounds was dissolved in 30 mL of methanol and stored at 4 °C. Different concentrations were obtained by diluting the stock solutions with ultrapure water. Scanning electron microscopy (SEM) was performed using an S-3700N instrument from Hitachi, Japan.

[0119] A schematic diagram illustrating the principle of solid-phase microextraction combined with portable mass spectrometry for detecting veterinary drugs is shown below. Figure 1As shown, portable mass spectrometry analysis was performed in positive ion mode using an electrospray ionization source and hyperbolic ion trap manufactured by Innovation Instruments Co., Ltd., Ningbo, China. The inlet temperature was maintained at 200°C, and the voltage of the electrospray ionization source was set to 2 kV. The jacket gas and auxiliary flow rates were both set to 2.5 L / min. -1 The transitions (m / z) of the five target analytes—sulfadiazine, thiabendazole, amantadine, ractopamine, and clenbuterol—and two competing compounds, bisacodyl and metronidazole, are shown in Table 2. The results of the five veterinary drugs detected by a portable mass spectrometer are as follows: Figure 2 As shown.

[0120] A mixed solution using these analytes was prepared at a concentration of 100 μg / mL. -1 The feasibility of simultaneously detecting sulfadiazine, thiabendazole, amantadine, ractopamine, and clenbuterol using a portable mass spectrometer was studied. The nitrogen flow rate and separation voltage amplitude were set to 4 L / min. -1 And 4V. All five substances were successfully detected, and their mass spectra are shown below. Figure 3 As shown in the figure. Notably, in positive ion mode, sulfadiazine exhibits a quasi-molecular ion peak at m / z 279, with secondary fragment ions mainly at m / z 260.7 and m / z 203. Similarly, thiabendazole shows a quasi-molecular ion peak at m / z 202, with secondary fragment ions mainly at m / z 131.7, m / z 163.4, and m / z 175. Amantadine's quasi-molecular ion peak appears at m / z 152.2, with secondary fragment ions mainly at m / z 135. Ractopamine has a quasi-molecular ion peak at m / z 302, with secondary fragment ions mainly at m / z 283.9 and m / z 164. Finally, clenbuterol's quasi-molecular ion peak corresponds to an exact molecular mass of m / z 277, with secondary fragment ions mainly at m / z 203 and m / z 259.8. These results highlight the applicability of portable mass spectrometry for the simultaneous detection of five veterinary drugs.

[0121] Table 2. Transitions (m / z) of the five target analytes and two competing compounds.

[0122]

[0123] Example 9

[0124] This example involves the analysis of a real sample, and the specific analysis method is as follows:

[0125] For the preparation of milk samples, 1 g of zinc sulfate, ZnSO4, and 1 g of potassium ferrocyanide, K4[Fe(CN)6]-3H2O were first added to 100 mL of milk. The mixture was vortexed for 2 s and then centrifuged at 10,000 rpm for 3 min to remove the bottom precipitate. This process was repeated twice until the sediment was negligible. The obtained supernatant was filtered through a 0.22 μm membrane. The pretreated sample was stored at 4 °C. Then, 10 mL of the filtrate obtained above was taken, and a solid-phase microextraction probe was immersed in it to enrich five veterinary drugs. The extraction temperature was room temperature (25 °C), and the stirring speed was 750 rpm·min. -1 The extraction time was 15 min; then the solid-phase microextraction probe was immersed in 200 μL of acetonitrile at room temperature for static desorption for 30 min; finally, the analysis was performed using a portable mass spectrometer.

[0126] Example 10

[0127] This example involves the analysis of a real sample, and the specific analysis method is as follows:

[0128] For the preparation of chicken samples, the meat was minced using a high-speed meat grinder and stored at -18°C. Then, 5.0 g of chicken was mixed with 20 mL of acetonitrile in a 50 mL centrifuge tube and stirred for 2 min. The mixture was centrifuged at 4500 rpm for 5 min. The supernatant was collected and dried with liquid nitrogen. The obtained sample was redissolved in 1 mL of 10% methanol aqueous solution and filtered through a 0.22 μm filter. Then, 10 mL of the filtrate was used to immerse a solid-phase microextraction probe to enrich five veterinary drugs. The extraction temperature was room temperature (25°C) and the stirring speed was 750 rpm·min. -1 The extraction time was 15 min; then the solid-phase microextraction probe was immersed in 20 μL of acetonitrile at room temperature for static desorption for 30 min.

[0129] The sample analysis results of Examples 9 and 10 are as follows:

[0130] The target analyte was not detected in either chicken or milk samples; therefore, samples were spiked at three concentration levels. According to Chinese National Standard GB 31650, the maximum residue limits for thiabendazole and sulfadiazine in meat and milk are 25 to 100 μg·kg⁻¹. -1 Furthermore, amantadine, clenbuterol hydrochloride, and ractopamine must not be detected in animal-derived meat samples. As shown in Table 3, the limit of quantification for thiabendazole is 86 μg·L⁻¹. -1 Therefore, the spiking levels for amantadine, clenbuterol, sulfadiazine, and ractopamine were set at 25 μg·kg⁻¹. -1 100 μg·kg -1 and 200 μg·kg-1 The spiking level for thiabendazole was set at 100 μg / kg. -1 200 μg·kg -1 and 500 μg·kg -1 Table 3 shows that the recoveries for milk samples ranged from 87% to 107%, and for chicken samples from 85% to 116%, with relative standard deviations of 2.6% to 14.7% and 2.1% to 13.9%, respectively. The developed solid-phase microextraction probe-portable mass spectrometry method demonstrates good accuracy and precision in the quantitative and qualitative determination of five target analytes in complex food samples.

[0131] Table 3. Spiking concentrations and recoveries of different target analytes in milk and muscle.

[0132]

[0133] Note: " / " indicates that this item is not present.

[0134] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A surface coating material for a solid-phase microextraction probe, characterized in that, The surface coating material is made by electrospinning a mixture of SBA-15 material, polyacrylonitrile and N,N-dimethylformamide. The ratio of the SBA-15 material, polyacrylonitrile, and N,N-dimethylformamide is 100mg~300mg: 100mg~300mg: 2mL~4mL; The SBA-15 material was prepared using the following method: S1: Add hydrochloric acid solution to the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and mix in a water bath to completely dissolve the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer. S2: Add tetraethyl silicate to a solution of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, mix in a water bath, and then carry out a hydrothermal synthesis reaction; S3: After the reaction is complete, filter to obtain a white precipitate, wash and dry for 8 hours; S4: Calcine the material after it has been dried overnight to synthesize SBA-15; The method for preparing the surface coating material of the solid-phase microextraction probe includes: S(1): Dissolve N,N-dimethylformamide in polyacrylonitrile; S(2): Add SBA-15 material to the mixture of polyacrylonitrile and N,N-dimethylformamide and stir for 2 to 3 hours to obtain an electrospinning coating solution containing SBA-15, which is the surface coating material.

2. A solid-phase microextraction probe, characterized in that, It includes a metal rod and a surface coating material coated on the outer surface of the metal rod, wherein the surface coating material is the electrospinning coating liquid as described in claim 1.

3. The method for preparing the solid-phase microextraction probe according to claim 2, characterized in that, include: Clean the surface of the metal rod with water and ethanol in turn to remove impurities, and then dry it for later use. The electrospinning coating solution was coated onto a dried metal rod by electrospinning to form a coating. The metal rod was then immersed in an ethanol solution and finally dried in a drying oven to obtain a solid-phase microextraction probe.

4. The method for preparing the solid-phase microextraction probe according to claim 3, characterized in that, The coating has a thickness of 265 μm and a length of 1 cm.

5. The method for preparing the solid-phase microextraction probe according to claim 3, characterized in that, The metal rod has a diameter of 980µm.

6. The application of the solid-phase microextraction probe according to claim 2 in veterinary drug detection.

7. The application of the solid-phase microextraction probe according to claim 6 in veterinary drug detection, characterized in that, The veterinary drugs tested were one or more of sulfadiazine, thiabendazole, amantadine, ractopamine, and clenbuterol.

8. The application of the solid-phase microextraction probe according to claim 7 in veterinary drug detection, characterized in that, Veterinary drug testing conditions include: Analysis was performed in positive ion mode using a portable mass spectrometer equipped with an electrospray ionization source and a hyperbolic ion trap. The inlet temperature was maintained at 200 °C, the voltage of the electrospray ionization source was set to 2 kV, and the jacket gas and auxiliary flow rates were both set to 2.5 L / min. -1 .

Images