Preparation method and application of halloysite-doped perfluoroalkyl hybrid material
By using perfluoroalkyl hybrid materials doped with elolite as adsorbents, providing both hydrophilic and hydrophobic adsorption sites, the problem of difficulty in adsorbing and detecting hydrophilic and hydrophobic antibiotics in milk and dairy products in the prior art is solved, and efficient antibiotic detection and analysis is achieved.
Patent Information
- Application Number
- CN202510094732.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2025-06-06
AI Technical Summary
The prior art is difficult to simultaneously absorb and detect hydrophilic and hydrophobic antibiotics in milk and dairy products, especially hydrophilic antibiotics, which have weak retention on hydrophobic adsorbents, resulting in a lower recovery rate.
Elolite-doped perfluoroalkyl hybrid materials are used as adsorbents, which provide both hydrophilic and hydrophobic adsorption sites by introducing perfluoroalkyl and other functional groups on the surface, thereby achieving efficient adsorption of hydrophilic and hydrophobic antibiotics.
It significantly improves the adsorption capacity and recovery of hydrophilic and hydrophobic antibiotics, reduces the matrix effect, improves the accuracy and sensitivity of detection, and can detect trace-level antibiotics.
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Figure CN120094555A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of detection of hydrophilic and hydrophobic antibiotics in food, and in particular to a preparation method of a perfluoroalkyl hybrid material doped with halloysite and an application thereof. The prepared perfluoroalkyl hybrid material is used as an adsorbent for detecting hydrophilic and hydrophobic antibiotics in milk and dairy products. Background Art
[0002] Antibiotics have attracted great interest worldwide because they are beneficial for preventing and treating animal diseases and are used as feed additives to promote animal growth. There are many types of antibiotics and their chemical properties vary greatly. For example, β-lactams (such as cefuroxime and cefoperazone) are hydrophilic substances, while macrolides (such as erythromycin, clarithromycin and roxithromycin) are hydrophobic substances. Antibiotic residues in milk and dairy products consumed daily can cause many problems for human health. According to Chinese regulations, the maximum residue limits (MRLs) of erythromycin in milk are less than 40 μg / kg. The EU MRLs for cefoperazone, cefuroxime and erythromycin in milk are 50, 50 and 40 μg / kg, respectively. In order to assess compliance with the MRLs, there is an urgent need to establish analytical methods to detect, quantify and validate these low-level antibiotics with different properties.
[0003] Milk and dairy products are rich in protein and fat. When using liquid chromatography-tandem mass spectrometry (LC-MS / MS) methods, complex matrices can lead to serious matrix effects, affecting the accuracy and sensitivity of the measurement. Therefore, it is necessary to develop effective sample pretreatment methods to reduce matrix effects. At present, the methods reported in the literature for the simultaneous determination of hydrophilic and hydrophobic antibiotics in milk and dairy products are mainly based on liquid-liquid extraction (LLE), or solid phase extraction (SPE), dispersed solid phase extraction (dSPE), magnetic extraction (MSPE), etc. The adsorbents used are mainly hydrophobic adsorbents, such as C18, Oasis (PRiME) HLB and hypercrosslinked polystyrene / F 3 O 4 etc. Since hydrophilic β-lactam antibiotics are poorly retained on hydrophobic adsorbents, the recovery rate is low. Considering the above, we believe that the development of an adsorbent based on a hydrophilic / hydrophobic mixed mode is of great significance for the purification of hydrophilic and hydrophobic antibiotics in milk and dairy products. However, the development of new adsorbents with good adsorption performance for both hydrophilic and hydrophobic analytes remains a great challenge.
[0004] Perfluoroalkyl compounds are widely used as modifiers for the preparation of fluorinated stationary phases due to their high electronegativity, strong hydrophobicity, low polarizability, and excellent chemical and thermal stability. In liquid chromatography separation, fluorinated stationary phases mainly exhibit hydrophobic, π-π, dipole-dipole, charge transfer, FF, hydrogen bonding, ion exchange and other effects. 8 F 13 The modified silica stationary phase as a separation medium exhibits a typical reverse phase mechanism. According to literature reports, the fluorinated stationary phase based on silica exhibits a hydrophilic mechanism for polar compounds, which is mainly caused by the silanol groups on the surface of the silica.
[0005] Therefore, the art hopes to develop a material that provides both hydrophilic and hydrophobic adsorption sites, so that the material can be used as an adsorbent to achieve the adsorption of hydrophilic and hydrophobic antibiotics by the same adsorbent, and the adsorbent can be used for the detection of antibiotics in milk and dairy products. Summary of the invention
[0006] The first technical problem to be solved by the present invention is to provide a preparation method of a perfluoroalkyl hybrid material doped with halloysite in view of the current status of the prior art.
[0007] The second technical problem to be solved by the present invention is to provide a perfluoroalkyl hybrid material doped with halloysite having a hydrophilic / hydrophobic mixed mode obtained by the above preparation method in view of the current status of the prior art, wherein the perfluoroalkyl hybrid material has adsorption properties for both hydrophilic and hydrophobic antibiotics.
[0008] The third technical problem to be solved by the present invention is to provide an application of the above-mentioned perfluoroalkyl hybrid material doped with halloysite in detecting hydrophilic and hydrophobic antibiotics in milk and dairy products in view of the current status of the prior art.
[0009] The fourth technical problem to be solved by the present invention is to provide a tube tip solid phase extraction column filled with the above-mentioned halloysite-doped perfluoroalkyl hybrid material in view of the current status of the prior art.
[0010] The fifth technical problem to be solved by the present invention is to provide a method for detecting hydrophilic and hydrophobic antibiotics in milk and dairy products by using the above-mentioned tube tip solid phase extraction column in view of the current status of the prior art.
[0011] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is: a method for preparing a perfluoroalkyl hybrid material doped with halloysite, comprising the following steps:
[0012] Step (1): adding halloysite to a sodium hexametaphosphate aqueous solution, subjecting it to ultrasonic treatment and stirring to obtain sodium hexametaphosphate purified halloysite;
[0013] Step (2): mixing halloysite purified by sodium hexametaphosphate, 1H, 1H, 2H, 2H-perfluoroalkyl triethoxysilane, tetraethoxysilane, aminopropyl triethoxysilane, PEG 10,000 and anhydrous ethanol, dissolving and dispersing by ultrasonic, adding water, shaking evenly and reacting in a water bath to obtain a perfluoroalkyl hybrid material doped with halloysite; wherein the number of carbon atoms of the alkyl group in the 1H, 1H, 2H, 2H-perfluoroalkyl triethoxysilane is 6 to 10. In the present invention, 1H,1H,2H,2H-perfluoroalkyltriethoxysilane can be one of the five components of 1H,1H,2H,2H-perfluorohexyltriethoxysilane, 1H,1H,2H,2H-perfluoroheptyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorononyltriethoxysilane and 1H,1H,2H,2H-perfluorodecyltriethoxysilane, or a combination of at least two of the five components.
[0014] Preferably, the 1H,1H,2H,2H-perfluoroalkyltriethoxysilane is 1H,1H,2H,2H-perfluorooctyltriethoxysilane.
[0015] Preferably, in the step (1), the mass concentration of the sodium hexametaphosphate aqueous solution is 0.05% to 0.25%, the mass volume ratio of halloysite to the sodium hexametaphosphate aqueous solution is 1g:8 to 20mL, the ultrasonic time is 10 to 20min, the stirring time is 30 to 60min, and the stirring is stopped after the end of stirring, and the precipitated part is discarded. The halloysite dispersed in the sodium hexametaphosphate aqueous solution is dried to obtain the sodium hexametaphosphate purified halloysite.
[0016] Preferably, in step (1), the mass concentration of the sodium hexametaphosphate aqueous solution is 0.1%, the mass volume ratio of halloysite to the sodium hexametaphosphate aqueous solution is 1 g:10 mL, the ultrasonic time is 15 min, and the stirring time is 45 min.
[0017] Preferably, in the step (2), the mass of halloysite purified by sodium hexametaphosphate is 720-1200 mg; the mass of PEG 10,000 is 600-1000 mg; the volume of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane is 1-2 mL; the volume of tetraethoxysilane is 2-3 mL; the volume of aminopropyltriethoxysilane is 2-3 mL; the volume of anhydrous ethanol is 3.00-8.00 mL, and the volume of water is 0.30-1.00 mL; the temperature of the water bath is 40-80° C., and the time of the water bath is 6-24 h.
[0018] Preferably, in the step (2), the mass of sodium hexametaphosphate purified halloysite is 960 mg; the mass of PEG 10,000 is 780 mg; the volume of 1H, 1H, 2H, 2H-perfluoroalkyl triethoxysilane is 1.18 mL; the volume of tetraethoxysilane is 2.24 mL; the volume of aminopropyl triethoxysilane is 2.36 mL; the volume of anhydrous ethanol is 4.35 mL; and the volume of water is 0.64 mL. In the present invention, the amount of each reaction component can be increased or decreased in proportion to the size of the specific reaction scale.
[0019] The technical solution adopted by the present invention to solve the above second technical problem is: a perfluoroalkyl hybrid material doped with halloysite prepared by the above preparation method.
[0020] The technical solution adopted by the present invention to solve the third technical problem is: an application of the above-mentioned perfluoroalkyl hybrid material in detecting hydrophilic and hydrophobic antibiotics in milk and dairy products.
[0021] The technical solution adopted by the present invention to solve the fourth technical problem is: a tube tip solid phase extraction column, wherein the tube tip solid phase extraction column is filled with the above-mentioned perfluoroalkyl hybrid material.
[0022] The technical solution adopted by the present invention to solve the fifth technical problem is: a method for detecting hydrophilic and hydrophobic antibiotics in milk and dairy products, characterized in that it comprises the following steps:
[0023] Step 1: Take an appropriate amount of milk and dairy products to be tested in a container;
[0024] Step 2: Add 1-3 g of sodium chloride and 10-20 mL of acetonitrile to the above container, shake, mix evenly, perform ultrasonic treatment for 30 min, centrifuge at a speed of 3000-5000×g for 5-10 min, and take the upper clear liquid; add 8-15 mL of cyclohexane to the supernatant, shake for 1-5 min, centrifuge at a speed of 3000-5000×g for 5-10 min; discard the cyclohexane layer, blow dry with nitrogen at 30-45° C., redissolve the hydrophilic antibiotic with 200-500 μL of 95-98% acetonitrile, and redissolve the hydrophobic antibiotic with 200-500 μL of 0-3% methanol to obtain an extract of milk and dairy products;
[0025] Step 3: The tip solid phase extraction column is rinsed with 200-1000 μL pure acetonitrile and 200-1000 μL pure water respectively; for the analysis of hydrophilic antibiotics, 200-1000 μL 95%-98% acetonitrile is used for equilibration, and for the analysis of hydrophobic antibiotics, 200-1000 μL 0-3% methanol is used for equilibration, and both are centrifuged at 424×g for 10 min; the milk and dairy product extract obtained in step 2 is transferred to the tip solid phase extraction column, and the sample is loaded by centrifugation at 106-424×g for 5-15 min; the hydrophilic antibiotics are eluted with 500 μL 50 mmol / L ammonium acetate (pH 5.00) containing 60% acetonitrile by volume, and the hydrophobic antibiotics are eluted with 500 μL 100 mmol / L ammonium acetate (pH 5.00) containing 60% methanol by volume. 6.56) elution, centrifugation at 106-238×g for 10 min to obtain the eluate;
[0026] Step 4: Filter the eluate and directly perform liquid chromatography-mass spectrometry detection.
[0027] Compared with the prior art, the advantages of the present invention are:
[0028] (1) The surface of the perfluoroalkyl hybrid material doped with halloysite prepared by the present invention contains perfluoroalkyl groups, and the perfluoroalkyl groups are used as the functional groups of the adsorbent, and hydrophilic and hydrophobic adsorption sites are provided at the same time, so that the same adsorbent can adsorb hydrophilic and hydrophobic antibiotics; the perfluorooctyl hybrid material doped with halloysite of the present invention can have hydrophilic interactions with hydrophilic antibiotics, and the adsorption capacity of the hydrophilic antibiotic cefoperazone is as high as 48.3 mg / g; the perfluorooctyl hybrid material doped with halloysite of the present invention can also have hydrophobic interactions with hydrophobic antibiotics, and the adsorption capacity of the hydrophobic antibiotic roxithromycin reaches 18.6 mg / g;
[0029] (2) Compared with the hybrid material without perfluoroalkyl, the perfluoroalkyl hybrid material doped with halloysite prepared by the present invention has an adsorption capacity of 3.6 times for the hydrophilic antibiotic cefoperazone and 9.8 times for the hydrophobic antibiotic roxithromycin, which is beneficial for the detection of trace hydrophilic and hydrophobic antibiotics in milk and dairy products;
[0030] (3) The present invention fills the perfluoroalkyl hybrid material doped with halloysite on the tip solid phase extraction column, and uses centrifugation to purify the impurities in milk and dairy products, which significantly reduces the matrix effect and improves the accuracy of detection. The matrix effect is reduced from 49-148% before purification to 90-104% after purification, meeting the matrix effect range of 80-120% that can be ignored for detection.
[0031] (4) The tip solid phase extraction method based on the perfluoroalkyl hybrid material doped with halloysite of the present invention is used to detect trace hydrophilic and hydrophobic antibiotics in milk and dairy products, with the lowest detection limit as low as 0.01 to 0.03 μg / kg, thereby improving the sensitivity of detecting hydrophilic and hydrophobic antibiotics. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 Schematic diagram of preparation of perfluorooctyl hybrid material doped with halloysite in an embodiment of the present invention;
[0033] Figure 2 The scanning electron microscope images of the hybrid materials prepared by different preparation methods in the embodiments of the present invention are shown; wherein,
[0034] Figure 2 a is a scanning electron micrograph of halloysite purified by sodium hexametaphosphate (Purified HNTs);
[0035] Figure 2 b is a scanning electron microscope image of the perfluorooctyl hybrid material (PFOTS monolith) in Comparative Example 3;
[0036] Figure 2 c is a scanning electron microscope image of the perfluorooctyl hybrid material (HNTs-PFOTS monolith) doped with halloysite in Example 1 at a magnification of 10,000 times;
[0037] Figure 2 d is a scanning electron microscope image of the perfluorooctyl hybrid material (HNTs-PFOTS monolith) doped with halloysite in Example 1 at a magnification of 30,000 times;
[0038] Figure 3 The thermogravimetric and differential thermogravimetric analysis diagrams (a), infrared spectra (b) and X-ray diffraction diagrams (c) of hybrid materials prepared by different preparation methods in the embodiments of the present invention; among them, sodium hexametaphosphate purified halloysite (Purified HNTs), perfluorooctyl hybrid material (PFOTS monolith) and perfluorooctyl hybrid material doped with halloysite (HNTs-PFOTS monolith);
[0039] Figure 4 The X-ray photoelectron spectra of the hybrid materials prepared by different preparation methods in the embodiments of the present invention are as follows:
[0040] Figure 4 a is the X-ray photoelectron spectrum of halloysite purified by sodium hexametaphosphate (Purified HNTs);
[0041] Figure 4b is the X-ray photoelectron spectrum of the perfluorooctyl hybrid material (HNTs-PFOTS monolith) doped with halloysite in Example 1. DETAILED DESCRIPTION
[0042] The present invention is further described in detail below with reference to the accompanying drawings.
[0043] Example 1 Preparation of Halloysite-doped Perfluorooctyl Hybrid Material (HNTs-PFOTS Monolith)
[0044] Step (1): 20 g of halloysite is added to 200 mL of a sodium hexametaphosphate aqueous solution with a mass concentration of 0.05%, subjected to ultrasonic treatment for 15 min, magnetic stirring for 30 min, and allowed to stand for 20 min. The precipitate is discarded, and the halloysite dispersed in the sodium hexametaphosphate aqueous solution is collected by centrifugation, washed with water for 2 to 3 times, and dried at 85° C. for 7 h to obtain sodium hexametaphosphate purified halloysite (Purified HNTs);
[0045] Step (2): 960 mg of sodium hexametaphosphate purified halloysite (Purified HNTs), 1.18 mL of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOTS), 2.24 mL of tetraethoxysilane (TEOS), 2.36 mL of aminopropyltriethoxysilane (APTES), 780 mg of PEG 10,000 and 4.35 mL of anhydrous ethanol were mixed, ultrasonicated at 50° C. for 30 min, 0.64 mL of water was added, and after oscillation, the mixture was reacted in a water bath at 80° C. for 6 h; the obtained material was washed with anhydrous ethanol to obtain a perfluorooctyl hybrid material doped with halloysite (HNTs-PFOTS monolith);
[0046] The purified HNTs and the HNTs-PFOTS monolith prepared in this example were subjected to scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) tests. The results are as follows: Figure 2 , 3 As shown in a, 3b, 3c, and 4.
[0047] Example 2 Preparation of Halloysite-doped Perfluorooctyl Hybrid Material (HNTs-PFOTS Monolith)
[0048] The same as Example 1, except that the amount of sodium hexametaphosphate purified halloysite (Purified HNTs) used in step (2) is 480 mg.
[0049] Example 3 Preparation of Halloysite-doped Perfluorooctyl Hybrid Material (HNTs-PFOTS Monolith)
[0050] The same as Example 1, except that the amount of sodium hexametaphosphate purified halloysite (Purified HNTs) used in step (2) is 720 mg.
[0051] Example 4 Preparation of Halloysite-doped Perfluorooctyl Hybrid Material (HNTs-PFOTS Monolith)
[0052] The same as Example 1, except that the amount of sodium hexametaphosphate purified halloysite (Purified HNTs) used in step (2) is 1200 mg.
[0053] Example 5 Preparation of Halloysite-doped Perfluorodecyl Hybrid Material
[0054] The same as Example 1, the only difference is that the 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTS) used in step (2) is changed to 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTS).
[0055] Example 6 Preparation of Halloysite-doped Perfluorohexyl Hybrid Material
[0056] The same as Example 1, the only difference is that the 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTS) used in step (2) is changed to 1H,1H,2H,2H-perfluorohexyltriethoxysilane (PFHTS).
[0057] Example 7 Preparation of Halloysite-doped Perfluorooctyl Hybrid Material (HNTs-PFOTS Monolith)
[0058] Step (1): 10 g of halloysite is added to 200 mL of a sodium hexametaphosphate aqueous solution with a mass concentration of 0.25%, subjected to ultrasonic treatment for 10 min, magnetic stirring for 45 min, and allowed to stand for 20 min. The precipitate is discarded, and the halloysite dispersed in the sodium hexametaphosphate aqueous solution is collected by centrifugation, washed with water for 2 to 3 times, and dried at 90° C. for 5 h to obtain sodium hexametaphosphate purified halloysite (Purified HNTs);
[0059] Step (2): 720 mg of sodium hexametaphosphate purified halloysite (Purified HNTs), 1 mL 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOTS), 2 mL tetraethoxysilane (TEOS), 2 mL aminopropyltriethoxysilane (APTES), 600 mg PEG 10,000 and 3 mL anhydrous ethanol were mixed, ultrasonicated at 40° C. for 60 min, 0.3 mL of water was added, and after oscillation, the mixture was reacted in a water bath at 40° C. for 24 h; the obtained material was washed with anhydrous ethanol to obtain a perfluorooctyl hybrid material doped with halloysite (HNTs-PFOTS monolith).
[0060] Example 8 Preparation of Halloysite-doped Perfluorooctyl Hybrid Material (HNTs-PFOTS Monolith)
[0061] Step (1): 20 g of halloysite is added to 160 mL of a sodium hexametaphosphate aqueous solution with a mass concentration of 0.15%, subjected to ultrasonic treatment for 20 min, magnetic stirring for 60 min, and allowed to stand for 20 min. The precipitate is discarded, and the halloysite dispersed in the sodium hexametaphosphate aqueous solution is collected by centrifugation, washed with water for 2 to 3 times, and dried at 80° C. for 8 h to obtain sodium hexametaphosphate purified halloysite (Purified HNTs);
[0062] Step (2): 1200 mg of sodium hexametaphosphate purified halloysite (Purified HNTs), 2 mL of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOTS), 3 mL of tetraethoxysilane (TEOS), 3 mL of aminopropyltriethoxysilane (APTES), 1000 mg of PEG 10,000 and 8 mL of anhydrous ethanol were mixed, ultrasonicated at 60° C. for 15 min, 1 mL of water was added, and after oscillation, the mixture was reacted in a water bath at 80° C. for 6 h; the obtained material was washed with anhydrous ethanol to obtain a perfluorooctyl hybrid material doped with halloysite (HNTs-PFOTS monolith).
[0063] Comparative Example 1
[0064] The same as Example 1, except that 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTS) is not added in step (2).
[0065] Comparative Example 2
[0066] The method is the same as Example 1, except that: in step (2), sodium hexametaphosphate purified halloysite (PurifiedHNTs) and 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTS) are not added.
[0067] Comparative Example 3 Preparation of perfluorooctyl hybrid material (PFOTS monolith)
[0068] The same as Example 1, the only difference is that: in step (2), sodium hexametaphosphate is not added to purify halloysite (PurifiedHNTs), and the obtained material is a perfluorooctyl hybrid material (PFOTS monolith). The perfluorooctyl hybrid material (PFOTS monolith) prepared in this comparative example was tested by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results are as follows: Figure 2 , 3 As shown in a, 3b, 3c, and 4.
[0069] The key experimental parameters in the above Examples 1 to 6 and Comparative Examples 1 to 3, the reagent passing capacity of the obtained hybrid materials, and the maximum adsorption capacity of the obtained hybrid materials for cefoperazone and roxithromycin are shown in Table 1. Although the adsorption capacity of the perfluorooctyl hybrid material doped with halloysite prepared in Example 1 for hydrophilic antibiotics did not reach the maximum value (48.3 mg / g), its adsorption capacity for hydrophobic antibiotics reached the maximum value (18.6 mg / g). Taking all factors into consideration, the perfluorooctyl hybrid material doped with halloysite prepared in Example 1 can provide a large adsorption capacity for both hydrophilic and hydrophobic antibiotics, has the best performance, and can meet the analysis requirements of both hydrophilic and hydrophobic antibiotics. The hybrid material prepared in Comparative Example 1 has poor permeability, and it is difficult for the solution to pass through the tip solid phase extraction column filled with it, and the maximum adsorption capacities for hydrophilic and hydrophobic antibiotics are only 13.3 and 1.9 mg / g, respectively, that is, there is almost no adsorption of hydrophobic antibiotics. In the hybrid material prepared in Comparative Example 2, the solvent cannot pass through the tip solid phase extraction column filled with it. The material prepared in Comparative Example 3 has an adsorption capacity of 36.9 mg / g for hydrophilic antibiotics, but only 4.8 mg / g for hydrophobic antibiotics. Therefore, the perfluorooctyl hybrid material doped with halloysite prepared in the present application has a large adsorption capacity for hydrophilic and hydrophobic antibiotics, which is beneficial to the detection of trace hydrophilic and hydrophobic antibiotics.
[0070] Table 1 Solvent passing capacity and maximum adsorption capacity of hybrid materials prepared by different preparation methods.
[0071]
[0072] a Using 424 × g, the reagents permeate the capacity of the sorbent-filled pipette tip.
[0073] b The maximum adsorption capacity of cefoperazone.
[0074] c The maximum adsorption capacity of roxithromycin.
[0075] SEM results analysis: Figure 2 a It can be seen that the halloysite purified by sodium hexametaphosphate (Purified HNTs) presents a fiber structure with a length of about 1 μm; Figure 2 In b, the perfluorooctyl hybrid material (PFOTS monolith) presents an irregular block structure of about 50 μm; when halloysite is doped into the perfluorooctyl hybrid material (PFOTS monolith), the morphology changes greatly, such as Figure 2 As shown in Figures 2c and 2d, the hybrid material formed by the interweaving of countless fibers has through pores of 1 to 5 μm, which is conducive to solvent penetration, further confirming that halloysite plays an important role in the formation of the overall material structure.
[0076] Analysis of thermogravimetric and differential thermogravimetric analysis results: Figure 3 As shown in a, below 200 °C is the dehydration drying process of the three samples and the evaporation process of the residual solvent in the perfluorooctyl hybrid material and the doped halloysite perfluorooctyl hybrid material; 450-525 °C is the main decomposition stage of the purified halloysite, the differential thermogravimetric (DTG) peak is at 502 °C, the mass loss is about 13.06%, and its crystal structure is destroyed, mainly due to the dehydroxylation of the Al-OH group in the halloysite; except for the first stage temperature below 200 °C, the perfluorooctyl hybrid material and the doped halloysite perfluorooctyl hybrid material both present the second and third stages; for the perfluorooctyl hybrid material, the mass loss in the second stage (i.e., 200-475 °C) is about 40.08%, and the mass loss in the third stage (i.e., 475-600 °C) is about 28.02%, which are attributed to the breakage of the polymer chain (i.e., perfluoroalkyl chain and aminopropyl) and the SiO 2 The dehydration of silanol groups in the network; in the second stage, a mass loss of about 14.66% was observed in the doped halloysite perfluorooctyl hybrid material; in the third stage, the DTG peak (580℃) of the doped halloysite perfluorooctyl hybrid material was higher than that of the perfluorooctyl hybrid material (502℃), indicating that the doped halloysite perfluorooctyl hybrid material has higher thermal stability. In addition, the mass losses of purified halloysite, perfluorooctyl hybrid material and doped halloysite perfluorooctyl hybrid material in the range of 35-800℃ were 16.74%, 71.15% and 48.22%, respectively, which further indicates that halloysite can significantly improve the thermal stability of the hybrid material.
[0077] Infrared spectrum analysis: Figure 3 b shows that the purified halloysite has a peak at 3697 and 3622 cm -1The double peaks at 468 and 910 cm are due to the stretching vibration of Al-OH on the inner surface; -1 The peaks at 1138, 1190, and 1235 cm-1 are attributed to the bending vibrations of Si-O-Si and internal surface hydroxyl groups in purified halloysite, respectively; according to the FTIR spectrum of the perfluorooctyl hybrid material, the peaks at 1138, 1190, and 1235 cm-1 are attributed to the bending vibrations of Si-O-Si and internal surface hydroxyl groups in the purified halloysite, respectively. -1 The characteristic peak is designated as -CF 2 and -CF 3 Group vibration, 629cm -1 The low intensity peak at is attributed to -CF 2 Bond stretching and rocking vibrations; 2936 and 2876 cm -1 The characteristic peaks correspond to the symmetric and asymmetric stretching vibrations of CH; in the FTIR spectrum of the halloysite-doped perfluorooctyl hybrid material, the characteristic peaks of the purified halloysite and perfluorooctyl hybrid material were observed at the same time, confirming that the halloysite-doped perfluorooctyl hybrid material has been successfully prepared.
[0078] X-ray diffraction pattern analysis: Figure 3 c It can be seen that the characteristic diffraction peak of the perfluorooctyl hybrid material and the halloysite-doped perfluorooctyl hybrid material at 2θ=23° is the characteristic peak of amorphous silica; the four characteristic diffraction peaks of the purified halloysite and the halloysite-doped perfluorooctyl hybrid material at 2θ=20.073°, 24.571°, 35.022° and 62.585° correspond to the (100), (002), (110) and (300) crystal planes of halloysite-7A, respectively (JCPDS29–1487). The results show that the crystal structures of amorphous silica and halloysite coexist in the halloysite-doped perfluorooctyl hybrid material.
[0079] X-ray photoelectron spectroscopy results analysis: Figure 4 As shown in Figure a, characteristic peaks of O1s, Si 2p, Al2p and C1s were observed in the purified halloysite, wherein O, Si and Al are characteristic elements of halloysite, and C may be an impurity in halloysite or an impurity introduced during the purification process; in addition to the characteristic peaks of halloysite, characteristic peaks of N1s and F1s were further observed in the doped halloysite perfluorooctyl hybrid material, i.e., the material contained N and F. These data indicate that the doped halloysite perfluorooctyl hybrid material of Example 1 was successfully prepared.
[0080] Example 9: Packing of the Tip Solid Phase Extraction Column
[0081] Place a sieve plate or cotton wool at the bottom of the pipette tip, weigh 15 mg of the perfluorooctyl hybrid material doped with halloysite and put it into the pipette tip, press it with the sieve plate or cotton wool, and set aside. The volume of the pipette tip can be 20, 200 or 1000 μL; the mass of the perfluorooctyl hybrid material doped with halloysite is 5 to 30 mg. In some embodiments, the filling method of the tube tip solid phase extraction column is as above, except that the material placed is different.
[0082] Example 10 Application of Halloysite-doped Perfluorooctyl Hybrid Materials in Detecting Hydrophilic and Hydrophobic Antibiotics in Milk and Dairy Products
[0083] Step 1: Take 5 g of whole milk powder purchased from a local supermarket in a 50 mL plastic centrifuge tube, and simultaneously add different volumes and concentrations of standard solutions of two hydrophilic antibiotics, cefuroxime and cefoperazone, so that the final concentrations of cefuroxime and cefoperazone are 0.1, 0.2 and 5.0 μg / kg, respectively; or simultaneously add different volumes and concentrations of standard solutions of three hydrophobic antibiotics, erythromycin, clarithromycin and roxithromycin, so that the final concentrations of erythromycin, clarithromycin and roxithromycin are 0.1, 0.2 and 5.0 μg / kg, respectively, to obtain whole milk powder samples in which different substances to be detected are dissolved and the concentrations of the substances to be detected are different;
[0084] Step 2: Add 2 g of sodium chloride and 15 mL of acetonitrile to the above container, shake, mix evenly, perform ultrasonic treatment for 30 min, centrifuge at 4000×g for 5 min, and take the upper clear liquid; add 10 mL of cyclohexane to the supernatant, shake for 1 min, and centrifuge at 4000×g for 5 min; discard the cyclohexane layer, blow dry with nitrogen at 40°C, redissolve the hydrophilic antibiotic with 500 μL of 98% acetonitrile by volume, and redissolve the hydrophobic antibiotic with 500 μL of 3% methanol by volume to obtain an extract of whole milk powder;
[0085] Step 3: The tip solid phase extraction column filled with the perfluorooctyl hybrid material doped with halloysite was rinsed with 1000 μL pure acetonitrile and 1000 μL pure water respectively, and the hydrophilic antibiotic analysis was balanced with 1000 μL 98% acetonitrile, and the hydrophobic antibiotic analysis was balanced with 1000 μL 3% methanol, and both were centrifuged at 424×g for 10 min; the extract of the whole milk powder obtained in step 2 was transferred to the tip solid phase extraction column, and the sample was loaded by centrifugation at 424×g for 10 min; the hydrophilic antibiotics were eluted with 500 μL of 50 mmol / L ammonium acetate (pH 5.00) containing 60% acetonitrile by volume, and the hydrophobic antibiotics were eluted with 500 μL of 100 mmol / L ammonium acetate (pH 6.56) containing 60% methanol by volume to obtain an eluent;
[0086] Step 4: Filter the eluate and perform liquid chromatography-mass spectrometry detection.
[0087] Liquid chromatography-mass spectrometry detection method:
[0088] A) Liquid Chromatography Separation
[0089] Hydrophilic antibiotics: Chromatographic column: Waters Atiantis HILIC Silica column (100mm×2.1mm, 5μm); flow rate: 0.3mL / min; column temperature: 30℃; injection volume: 5μL; gradient separation was adopted for mobile phase: the mobile phase (A) was 10mmol / L ammonium formate aqueous solution containing 0.1% formic acid, and the mobile phase (B) was acetonitrile, and the gradient was as follows: 0–1.5min, 90–90% B; 1.5–2.0min, 90–70% B; 2.0–2.5min, 70–60% B; 2.5–3.5min, 60% B; 3.5–5.0min, 60–90% B; 5.0–8.0min, 90–90% B.
[0090] Hydrophobic antibiotics: Chromatographic column: Agilent Zorbax SB-C18 column (150mm×4.6mm, 5μm); flow rate: 0.8mL / min; column temperature: 30℃; injection volume: 5μL; mobile phase was gradient separation: mobile phase (A) was water containing 0.1% formic acid, mobile phase (B) was methanol containing 0.1% formic acid, the gradient was as follows: 0.0–2.0min, 15–20% B; 2.0–4.0min, 20–40% B; 4.0–5.0min, 40–60% B; 5.0–6.0min, 60–90% B; 6.0–7.0min, 90–95% B; 7.0–12.0min, 95% B; 12.0–13.0min, 95–15% B; 13–18min, 15% B.
[0091] B) Mass spectrometry detection
[0092] Hydrophilic antibiotics: Cefoperazone was scanned with positive ions, and cefuroxime was scanned with negative ions. The hydrophilic antibiotics were quantitatively analyzed in the multiple reaction monitoring (MRM) mode. The detection parameters were as follows: the capillary voltage was 3.0 and -1.6 kV, respectively; the ion source temperature was 150 °C; the desolvation temperature was 500 and 350 °C, respectively; the cone gas flow rate was 150 L / h, and the desolvation gas volume flow rate was 950 and 650 L / h, respectively.
[0093] Hydrophobic antibiotics: Positive ion scanning was used to quantitatively analyze hydrophobic antibiotics in the multiple reaction monitoring (MRM) mode, and the detection parameters were as follows: ion source temperature was 600°C; spray voltage: 4.5 kV; spray gas (gas 1) pressure, 55 psi; auxiliary heating gas (gas 2) pressure, 55 psi; curtain gas pressure, 30 psi; collision gas pressure was set to medium.
[0094] The quantitative and confirmation parameters of the MRM mode for the five antibiotics are shown in Table 2:
[0095] Table 2 Quantification and confirmation parameters of the MRM mode for five antibiotics.
[0096]
[0097] *Quantitative ion
[0098] In this example, the tip solid phase extraction column filled with the halloysite-doped perfluorooctyl hybrid material prepared in Example 1 was used to detect different types of antibiotics in whole milk powder by centrifugation, and the results are listed in Table 3.
[0099] Example 11 Application of Halloysite-doped Perfluorooctyl Hybrid Materials in Detecting Hydrophilic and Hydrophobic Antibiotics in Milk and Dairy Products
[0100] In this embodiment, skimmed milk powder is used as the sample, and the remaining steps are the same as those in Example 10.
[0101] Example 12 Application of Halloysite-doped Perfluorooctyl Hybrid Materials in Detecting Hydrophilic and Hydrophobic Antibiotics in Milk and Dairy Products
[0102] In this embodiment, skimmed goat milk powder is used as the sample, and the remaining steps are the same as those in Example 10.
[0103] Example 13 Application of Halloysite-doped Perfluorooctyl Hybrid Materials in Detecting Hydrophilic and Hydrophobic Antibiotics in Milk and Dairy Products
[0104] In this embodiment, the sample is whole goat milk powder, and the remaining steps are the same as those in Example 10.
[0105] Example 14 Application of Halloysite-doped Perfluorooctyl Hybrid Materials in Detecting Hydrophilic and Hydrophobic Antibiotics in Milk and Dairy Products
[0106] In this embodiment, the sample is whole camel milk powder, and the remaining steps are the same as those in Example 10.
[0107] Example 15 Application of Halloysite-doped Perfluorooctyl Hybrid Materials in Detecting Hydrophilic and Hydrophobic Antibiotics in Milk and Dairy Products
[0108] In this embodiment, milk is used as the sample, and the remaining steps are the same as those in Embodiment 10.
[0109] Table 3 Recoveries of hydrophilic and hydrophobic antibiotics in milk and dairy products at different spike concentrations (n = 3).
[0110]
[0111]
[0112] As shown in Table 3, the intra-day and inter-day recoveries of the five antibiotics were between 81.8% and 108.1% and 80.0% and 112.3%, and the relative standard deviations (RSDs) were between 0.4% and 8.8% and 1.0% and 10.9%, respectively, with high recovery and good reproducibility. The minimum detection limit and minimum quantification limit of the five antibiotics were 0.01% to 0.03% and 0.03% to 0.08 μg / kg, respectively. The whole milk powder extract extracted in step 2 was directly detected by liquid chromatography-mass spectrometry. The matrix effects of the five antibiotics were between 49% and 148%. After the purification of the tip solid phase extraction column based on the perfluorooctyl hybrid material doped with halloysite in step 3, the matrix effects of the five antibiotics were between 90% and 104%, which greatly reduced the matrix effect and improved the accuracy of the determination.
Claims
1. A method for preparing a perfluoroalkyl hybrid material doped with halloysite, characterized in that: The steps include: Step (1): adding halloysite to a sodium hexametaphosphate aqueous solution, subjecting it to ultrasonic treatment and stirring to obtain sodium hexametaphosphate purified halloysite; Step (2): mixing halloysite purified by sodium hexametaphosphate, 1H, 1H, 2H, 2H-perfluoroalkyl triethoxysilane, tetraethoxysilane, aminopropyl triethoxysilane, PEG 10,000 and anhydrous ethanol, dissolving and dispersing by ultrasonic, adding water, shaking evenly and reacting in a water bath to obtain a perfluoroalkyl hybrid material doped with halloysite; wherein the number of carbon atoms of the alkyl group in the 1H, 1H, 2H, 2H-perfluoroalkyl triethoxysilane is 6 to 10.
2. The preparation method according to claim 1, characterized in that: The 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane is 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane.
3. The preparation method according to claim 1, characterized in that: In the step (1), the mass concentration of the sodium hexametaphosphate aqueous solution is 0.05% to 0.25%, the mass volume ratio of halloysite to the sodium hexametaphosphate aqueous solution is 1g:8-20mL, the ultrasonic time is 10-20min, the stirring time is 30-60min, and the stirring is stopped after the end, and the precipitate is discarded. The halloysite dispersed in the sodium hexametaphosphate aqueous solution is dried to obtain the sodium hexametaphosphate purified halloysite.
4. The preparation method according to claim 3, characterized in that: In the step (1), the mass concentration of the sodium hexametaphosphate aqueous solution is 0.1%, the mass volume ratio of halloysite to the sodium hexametaphosphate aqueous solution is 1 g:10 mL, the ultrasonic time is 15 min, and the stirring time is 45 min.
5. The preparation method according to claim 1, characterized in that: In the step (2), the mass of halloysite purified by sodium hexametaphosphate is 720-1200 mg; the mass of PEG 10,000 is 600-1000 mg; the volume of 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane is 1-2 mL; the volume of tetraethoxysilane is 2-3 mL; the volume of aminopropyltriethoxysilane is 2-3 mL; the volume of anhydrous ethanol is 3.00-8.00 mL, and the volume of water is 0.30-1.00 mL; the temperature of the water bath is 40-80° C., and the time of the water bath is 6-24 hours.
6. The preparation method according to claim 5, characterized in that: In the step (2), the mass of halloysite purified by sodium hexametaphosphate is 960 mg; the mass of PEG 10,000 is 780 mg; the volume of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane is 1.18 mL; the volume of tetraethoxysilane is 2.24 mL; the volume of aminopropyltriethoxysilane is 2.36 mL; the volume of anhydrous ethanol is 4.35 mL; and the volume of water is 0.64 mL.
7. A perfluoroalkyl hybrid material doped with halloysite obtained by the preparation method according to any one of claims 1 to 6.
8. Use of the perfluoroalkyl hybrid material as claimed in claim 7 in detecting hydrophilic and hydrophobic antibiotics in milk and dairy products.
9. A tip solid phase extraction column, characterized in that: The tube tip solid phase extraction column is filled with the perfluoroalkyl hybrid material as claimed in claim 7.
10. A method for detecting hydrophilic and hydrophobic antibiotics in milk and dairy products, characterized in that: The steps include: Step 1: Take an appropriate amount of milk and dairy products to be tested in a container; Step 2: Add 1-3 g of sodium chloride and 10-20 mL of acetonitrile to the above container, shake, mix evenly, perform ultrasonic treatment for 30 min, centrifuge at a speed of 3000-5000×g for 5-10 min, and take the upper clear liquid; add 8-15 mL of cyclohexane to the supernatant, shake for 1-5 min, centrifuge at a speed of 3000-5000×g for 5-10 min; discard the cyclohexane layer, blow dry with nitrogen at 30-45° C., redissolve the hydrophilic antibiotic with 200-500 μL of 95-98% acetonitrile, and redissolve the hydrophobic antibiotic with 200-500 μL of 0-3% methanol to obtain an extract of milk and dairy products; Step 3: Rinse the tip solid phase extraction column of claim 9 with 200-1000 μL pure acetonitrile and 200-1000 μL pure water respectively; for the analysis of hydrophilic antibiotics, balance with 200-1000 μL 95%-98% acetonitrile, and for the analysis of hydrophobic antibiotics, balance with 200-1000 μL 0-3% methanol, and centrifuge at 424×g for 10 min; transfer the milk and dairy product extract obtained in step 2 to the tip solid phase extraction column, and complete the loading by centrifugation at 106-424×g for 5-15 min; elute the hydrophilic antibiotics with 500 μL of 50 mmol / L ammonium acetate (pH 5.00) containing 60% acetonitrile by volume, and elute the hydrophobic antibiotics with 500 μL of 100 mmol / L ammonium acetate (pH 6.00) containing 60% methanol by volume. 6.56) elution, centrifugation at 106-238×g for 10 min to obtain the eluate; Step 4: Filter the eluate and directly perform liquid chromatography-mass spectrometry detection.