A highly sensitive, rapid, and visual method for detecting albendazole and albendazole sulfoxide residues in animal-derived foods

Abstract

The present invention discloses a method for highly sensitive, rapid and visual detection of albendazole and albendazole sulfoxide residues in animal-derived foods, belonging to the field of food safety technology. The present invention finds that the rare earth metal organic framework material EuUHC‑30 has a sensitive and specific fluorescence response to ABZ and ABZSO, which can be used to detect ABZ and ABZSO, and can also be used to prepare products for detecting ABZ and ABZSO. The present invention also uses EuUHC‑30 to prepare a test paper, which is combined with the color recognition software of an intelligent device to achieve portable, visual and rapid detection of ABZ and ABZSO. The results of the present invention for detecting ABZ and ABZSO are consistent with the results of HPLC analysis, providing an excellent fluorescent sensor and a portable, accurate, visible and on-site detection method for determining ABZ and ABZSO in animal-derived foods.

Description

Technical Field

[0001] The invention belongs to the technical field of food safety and relates to veterinary drug residue detection, and particularly relates to a method for highly sensitive, rapid and visual detection of albendazole and albendazole sulfoxide residues in animal-derived food. Background Art

[0002] Albendazole (ABZ), a benzimidazole anthelmintic, is the gold standard for treating helminthic infections due to its high efficacy. It is widely used in veterinary clinics for the prevention of parasitic infections (such as hookworms, roundworms, whipworms, pinworms, and trichinella spiralis) and in agriculture and aquaculture. Following oral administration, ABZ is rapidly metabolized to albendazole sulfoxide (ABZSO), albendazole sulfone, and albendazole-2-aminosulfone. Of these, only ABZSO exhibits anthelmintic activity. The widespread and inappropriate use of ABZ in animal husbandry has resulted in the generation of anthelmintic-resistant, toxic residues in animal-derived foods, potentially posing a health risk to humans. Long-term exposure to ABZ and ABZSO can lead to multiple adverse effects, including teratogenicity, polyploidy, congenital malformations, and pulmonary edema. Therefore, ABZ is not recommended for use in lactating dairy cows due to its prolonged metabolic period in animals. Governments in several countries have established maximum residue limits (MRLs) in animal-derived foods to protect human health. For example, the MRL for ABZ in milk is 100 μg / kg, 500 μg / kg in kidney, and 100 μg / kg in liver. However, some farmers still violate these regulations and use large amounts of ABZ for commercial gain. Therefore, further development of accurate and rapid detection methods for ABZ and ABZSO in animal-derived foods is desirable.

[0003] Numerous analytical methods, including capillary electrophoresis, fluorescence (HPLC-FL), ultraviolet high-performance liquid chromatography (HPLC-UV), liquid chromatography tandem mass spectrometry (LC-MS), micellar liquid chromatography (MLC), and ultra-high-performance liquid chromatography-fluorescence (UPLC-FLD), have been applied to the quantitative determination of ABZ and its metabolites in biological samples and animal-derived foods. However, these methods are time-consuming, require high-purity reagents, are relatively expensive, and require skilled operators. Therefore, the development of a low-cost, simple, and accurate method for the detection of ABZ is necessary.

[0004] In recent years, fluorescence-based methods have attracted significant attention due to their simplicity, visualization, real-time analysis, and cost-effectiveness. Among fluorescent materials, luminescent lanthanide metal-organic frameworks (Ln-MOFs) have garnered worldwide attention because they combine the inherent advantages of MOF materials with excellent luminescence properties, offering the possibility of rational design with desired structural and luminescent properties. Consequently, these luminescent Ln-MOFs have been extensively explored as chemical and biological sensors in recent years. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for highly sensitive, rapid and visual detection of albendazole and albendazole sulfoxide residues in animal-derived foods.

[0006] The present invention utilizes a dual-emission Eu-MOF (EuUHC-30) chemical sensor for detecting ABZ and ABZSO in animal-derived foods. EuUHC-30 is synthesized by post-modification of a UiO-66 material composed of 2-hydroxyterephthalic acid, 1,2,4,5-benzenetetracarboxylic acid, and ZrCl4. 3+ , EuUHC-30 exhibited dual emission bands, and was found to have sensitive and specific fluorescence responses to ABZ and ABZSO.

[0007] The dual-emission rare earth metal organic framework material EuUHC-30 can be synthesized by a method comprising the following steps:

[0008] (1) ZrCl4, 1,2,4,5-benzenetetracarboxylic acid, and 2-hydroxyterephthalic acid were added to water for reflux reaction, and the product obtained by centrifugation after cooling was refluxed again with water. The product obtained by centrifugation was washed three times with water and ethanol, and then dried to obtain UHC-30;

[0009] (2) UHC-30 added to Eu 3+ The reaction is carried out in an aqueous solution to obtain EuUHC-30.

[0010] In step (1), the reaction ratio of ZrCl4, 1,2,4,5-benzenetetracarboxylic acid, and 2-hydroxyterephthalic acid is 2.00mmol:2.8mmol:1.2mmol; the reflux reaction condition is preferably 100°C for 24 hours.

[0011] In step (2), the Eu 3+ The aqueous solution is preferably a Eu(NO3)3 aqueous solution, which is prepared by reacting UHC-30 and Eu(NO3)3 in a mass ratio of 1:1.3; the reaction conditions are preferably 80°C for 12 hours.

[0012] In its first aspect, the present invention provides the use of the dual-emission rare earth metal organic framework material EuUHC-30 as a fluorescence sensor for detecting ABZ and / or ABZSO. EuUHC-30's fluorescence at 450 nm and 614 nm is quenched by ABZ or ABZSO, respectively, within one minute. It also exhibits excellent resistance to interference from other veterinary drugs, some metal ions, and amino acids.

[0013] In a second aspect, the present invention provides a method for detecting ABZ and / or ABZSO, comprising the following steps: adding a test sample to a EuUHC-30 aqueous suspension, detecting changes in its fluorescence intensity at 450 nm or 614 nm, and detecting ABZ and / or ABZSO based on the fluorescence quenching effect.

[0014] In a third aspect, the present invention provides the use of a rare earth metal organic framework material EuUHC-30 in the preparation of products for detecting ABZ and / or ABZSO.

[0015] In a fourth aspect, the present invention provides a system for detecting ABZ and / or ABZSO, comprising: a test strip and a color recognition device. The test strip is impregnated or coated with a EuUHC-30 suspension. The color recognition device is preferably a smartphone installed with an RGB color value application. The test strip, coated with a suspension obtained by reacting EuUHC-30 with a standard concentration of ABZ or ABZSO, is photographed using a camera under ultraviolet light, and the linear relationship between the RGB values ​​of the photographed image and the ABZ and / or ABZSO concentration is determined.

[0016] In a fifth aspect, the present invention also provides a method for using the aforementioned system, combining it with RGB color values ​​assisted by a portable smartphone to achieve intelligent detection of ABZ and / or ABZSO. The method comprises the following steps: adding a test solution dropwise to a test strip to react and obtain the test strip; identifying the RGB values ​​of the test strip under ultraviolet light using a color recognition device; and comparing the RGB values ​​with the linear relationship between the RGB values ​​and the ABZ and / or ABZSO concentrations to determine the ABZ or ABZSO concentration in the test solution.

[0017] Advantages and benefits of the present invention: The present invention utilizes the rapid response of the fluorescence spectrum of the dual-emission rare earth metal organic framework material EuUHC-30 to ABZ and ABZSO, thereby achieving highly sensitive, rapid, and visual detection of ABZ and ABZSO. The method has been successfully applied to the detection of ABZ and ABZSO residues in actual milk and pig kidney samples, with the results consistent and reliable with HPLC analysis. Combining EuUHC-30 into test strips and color recognition equipment enables portable, visual, and rapid detection of ABZ and ABZSO. This present invention provides an excellent fluorescence sensor and a portable, accurate, visible, and on-site detection method for the determination of ABZ and ABZSO in animal-derived foods. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1The HPLC linear standard curves of ABZ (a) and ABZSO (b) at different concentrations (0-70 μM) in pig kidney samples and the HPLC linear standard curves of ABZ (c) and ABZSO (d) at different concentrations (0-70 μM) in milk samples were established.

[0019] Figure 2 Characterization results of the synthesized metal-organic frameworks. (a) XRD patterns of the synthesized materials; (b) Fluorescence emission spectra of UHC-x (x = 10, 30, 50, 70, 90); (c) Fluorescence emission spectra of EuUHC-x (x = 10, 30, 50, 70, 90); (d) Fluorescence distribution of EuUHC-x (x = 10, 30, 50, 70, 90) at 450 nm and 614 nm.

[0020] Figure 3 Characterization results of UHC-30 and EuUHC-30. (a) FT-IR spectra of UHC-30 and EuUHC-30; (b) EDS mapping spectrum of UHC-30; (c) EDS mapping spectrum of EuUHC-30; (d) XPS spectra of UHC-30 and EuUHC-30; (e) O1s spectra of UHC-30 and EuUHC-30; (f) SEM image of UHC-30; (g) SEM image of EuUHC-30; (h) Particle size distribution of UHC-30; (i) Particle size distribution of EuUHC-30; (j) TGA and DTG patterns of UHC-30 and EuUHC-30.

[0021] Figure 4 The optical properties of UHC-30 and EuUHC-30 are shown in Figure 2. (a) Solid-state fluorescence spectrum of UHC-30; (b) Liquid-state fluorescence spectrum of UHC-30; (c) Solid-state fluorescence spectrum of EuUHC-30; (d) Liquid-state fluorescence spectrum of EuUHC-30; (e) Fluorescence spectrum of EuUHC-30 aqueous suspension over seven days; (f) Changes in fluorescence intensity at 450 nm and 614 nm of EuUHC-30 aqueous suspension over seven days; (g) Fluorescence spectrum of EuUHC-30 aqueous suspension under different pH conditions; (h) Changes in fluorescence intensity at 450 nm and 614 nm of EuUHC-30 aqueous suspension under different pH conditions.

[0022] Figure 5 The results of EuUHC-30 detection of ABZ and ABZSO are shown in Figure 2. (a) Fluorescence spectra of EuUHC-30 in the presence of different concentrations of ABZ; (b) Fluorescence spectra of EuUHC-30 in the presence of different concentrations of ABZSO; (c) CIE graph in the presence of ABZ; (d) CIE graph in the presence of ABZSO; (e) (F0 / F)614 Linear relationship with different concentrations of ABZ; (f)(F0 / F) 450 Linear relationship with different concentrations of ABZ; (g)(F0 / F) 614 The linear relationship between different concentrations of ABZSO; (h)(F0 / F) 450 Linear relationship with different concentrations of ABZ; (i) Time response of ABZ and EuUHC-30; (j) Time response of ABZSO and EuUHC-30.

[0023] Figure 6 Interference resistance results of EuUHC-30 in detecting ABZ and ABZSO. (a) Fluorescence spectra of EuUHC-30 in the presence of various interfering substances; (b) Changes in relative fluorescence intensity of EuUHC-30 at 450 nm and 614 nm in the presence of various interfering substances; (c) Interference resistance histogram at 450 nm; (d) Interference resistance histogram at 614 nm.

[0024] Figure 7 This is a study on the fluorescence quenching mechanism of ABZ and ABZSO. (a) XRD pattern after the reaction of ABZ / ABZSO and EuUHC-30; (b) XPS N 1s pattern after the reaction of ABZ / ABZSO and EuUHC-30; (c) XPS Eu 3d pattern after the reaction of ABZ / ABZSO and EuUHC-30; (d) UV-vis spectra of ABZ, ABZSO, H4bect, and 2-htpa; (e) ABZ and ABZSO on Eu 3+ (f) Effect of ABZ and ABZSO on the fluorescence intensity of 2-htpa.

[0025] Figure 8 Figure 5 is the fluorescence emission spectra of EuUHC-30 in the presence and absence of milk and pig kidney samples.

[0026] Figure 9 It is the fluorescence graph of EuUHC-30 based paper strips under different concentrations of ABZ and ABZSO.

[0027] Figure 10 ABZ and ABZSO were quantified by smartphone imaging (the relationship between the RGB values ​​of fluorescence photos and the concentrations of ABZ and ABZSO). DETAILED DESCRIPTION

[0028] The following examples are intended to further illustrate the present invention but should not be construed as limiting the present invention. Any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principles of the present invention are considered equivalent substitutions and are included within the scope of protection of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0029] Example Synthesis of Dual-Emission Rare Earth Metal Organic Framework Material EuUHC-30 and Its Application in Detection of ABZ and ABZSO

[0030] 1. Experimental Methods

[0031] (1) Synthesis of UHC-30

[0032] ZrCl4 (466 mg, 2.00 mmol), 1,2,4,5-benzenetetracarboxylic acid (H4betc) (710 mg, 2.8 mmol) and 2-hydroxyterephthalic acid (2-htpa) (220 mg, 1.2 mmol) were mixed in H2O (25 mL) and then refluxed at 100°C for 24 hours. A white residue was obtained by centrifugation at 10,000 rpm for 8 minutes. The residue was refluxed in 200 mL of H2O and refluxed at 100°C for 1 day. After the suspension was cooled to room temperature, the residue was washed with H2O and CH3CH2OH and then dried at 80°C for 12 hours to obtain a white powder, thereby obtaining UHC-30.

[0033] (2) Synthesis of EuUHC-30

[0034] 500 mg of UHC-30 was immersed in 30 mL of a 0.05 M Eu(NO₃)₃·6H₂O aqueous solution and stirred at 80°C overnight. The resulting residue was centrifuged and filtered, then washed with H₂O and CH₃CH₂OH. The white powder was collected and dried at 80°C for 10 hours to obtain EuUHC-30.

[0035] (3) Luminescence sensing experiment

[0036] The luminescent response of EuUHC-30 to various substances that may be present in milk and pig kidney was studied. 25 mg of EuUHC-30 dry powder was dispersed in 50 mL of H2O and sonicated at room temperature for 20 minutes to obtain a uniform suspension. To each 2 mL of EuUHC-30 suspension was added 20 μL of 100 μM different substances, including lysine, leucine, tryptophan, DL-methionine, valine, proline, VC, fructose, glucose, K + 、Na + , Ca 2+chloramphenicol, lincomycin, avermectin, ivermectin, erythromycin, oxytetracycline, carbendazim, benomyl, fenbendazole, ABZ, and ABZSO were thoroughly mixed before fluorescence spectroscopy testing. To further investigate the anti-interference capability of the probe designed for monitoring ABZ and ABZSO, fluorescence spectra of the interfering species were recorded in the presence of ABZ or ABZSO. All fluorescence emission spectra were recorded at an excitation wavelength of 290 nm and a slit width of 1.5 nm / 1.5 nm.

[0037] (4) Detection of ABZ and ABZSO in pig kidney and milk samples

[0038] For pig kidney pretreatment, first, 5.00 g of uniform kidney tissue was mixed with 5 mL of phosphate buffered saline (PBS) and 10 mL of ethyl acetate, vortexed for 3 minutes, centrifuged at 6000 rpm for 8 minutes, and the organic layer was collected. The residue was extracted with 10 mL of ethyl acetate using the same steps. The two organic layers were combined and dried under a stream of N2 at 30 ° C. Then 5 mL of acetonitrile was added and vortexed for 5 minutes. The acetonitrile phase was washed three times with 5 mL of n-hexane, and the n-hexane phase was discarded. Finally, the acetonitrile phase was dried and redissolved with 1.00 mL of DMF, vortexed for 5 minutes, and the supernatant was collected by centrifugation. The standard concentrations of DMF solutions of ABZ and ABZSO were added to the above acetonitrile solution. 2 mL of EuUHC-30 suspension was added to each 20 μL sample for fluorescence and HPLC analysis ( Figure 1 (a), (b)).

[0039] For milk pretreatment, 5 mL of CH3OH was added to 2 mL of milk sample. The mixture was vortexed for 2 minutes and then centrifuged at 8000 rpm for 10 minutes. The supernatant was filtered through a 0.22 μm organic phase filter. ABZ and ABZSO DMF solutions of different standard concentrations were added to the filtrate. Subsequently, 20 μL of the sample was added to 2 mL of 0.5 mg / mL EuUHC-30 suspension for fluorescence and HPLC analysis ( Figure 1 (c), (d)).

[0040] 2. Results

[0041] (1) Design and characterization of metal-organic framework materials

[0042] UiO-66 type MOF was selected as the backbone structure of the probe due to its excellent physical and chemical stability. The introduction of 2-htpa not only serves as a linker, but more importantly as a blue emission component. H4bect, as a linker with an uncoordinated carboxylic acid group, can be further used to introduce strong red emission Eu through coordination bonds. 3+ions. The amount of luminescent components affects the fluorescence intensity, which determines the sensing performance. Therefore, different amounts of 2-HTPA (10%, 30%, 50%, 70% and 90%, 2-HTPA accounts for the molar fraction of the total ligand (2-HTPA + H4betc)) were added to prepare the precursor UHC-x (x = 10, 30, 50, 70 and 90), which was further used to generate the precursor UHC-x and Eu 3+ Eu-MOFs were synthesized by the coordination interaction between the uncoordinated carboxylic acid groups of the ions. As expected, a series of dual-emission EuUHC-x (x = 10, 30, 50, 70 and 90) were successfully fabricated. The PXRD patterns of the synthesized MOFs were exactly the same as those of the simulated UiO-66 and matched well, indicating that the synthesized MOFs were highly crystalline and isostructural with UiO-66, and the structural framework was retained after post-modification ( Figure 2 (a)). The photoluminescence spectra of the synthesized MOF dispersed in aqueous solution were studied. A strong emission band originating from 2-htpa was observed at 450 nm for UHC-x. 3+ After post-modification, in addition to the emission of 2-htpa, Eu 3+ The characteristic emission bands of Eu (579, 592, 614, 655, 700 nm) are shown. It is worth noting that the emission band at 450 nm increases slightly with the increase of 2-HTPA. 3+ The emission band is significantly reduced ( Figure 2 (b), (c)). Since good fluorescence sensing performance requires high emission intensity, it is assumed that [Score] = [F / F max ] 450nm +[F / F max ] 614nm standards to describe emission performance. Figure 2 (d) shows that EuUHC-30 scored the highest, therefore, it was selected for detailed characterization and fluorescence sensing studies.

[0043] The FT-IR spectra of UHC-30 and EuUHC-30 are shown in Figure 2. Figure 3 (a) 1585cm -1 and 1395cm -1 The strong vibration bands at 1710 cm-1 are attributed to the asymmetric and symmetric stretching vibrations of carboxylates, respectively. -1 The stretching vibration of the free -COOH group in UHC-30 was observed, which was very weak in EuUHC-30, indicating that the free -COOH group and Eu 3+ ICP-MS analysis confirmed that Eu 3+ Ion encapsulation in EuUHC-30. Zr 4+ and Eu 3+The calculated molar ratio of ions is 1:0.125. Energy dispersive X-ray spectroscopy (EDS) elemental mapping also proves that Eu in EuUHC-30 3+ Successful encapsulation and uniform distribution ( Figure 3 (b), (c)). X-ray photoelectron spectroscopy (XPS) was used to investigate the chemical composition of MOF. Figure 3 (d) shows that compared with UHC-30, a new photoelectron line is observed at 1135.45 eV in EuUHC-30, which corresponds to the binding energy of Eu 3d, further verifying that Eu in EuUHC-30 3+ ions. At the same time, the binding energy of O1s in UHC-30 at 531.54eV moves to 531.71eV in EuUHC-30 ( Figure 3 (e)), indicating that Eu 3+ and UHC-30. SEM images show that there is no significant difference between UHC-30 and EuUHC-30 ( Figure 3 (f), (g)), they are all crystallized in regular octahedral nanoparticles, indicating that the 3+ The average sizes of UHC-30 and EuUHC-30 are 252nm and 240nm respectively. Figure 3 (h), (i)). Thermogravimetric analysis (TGA) and differential thermal analysis (DTG) showed that UHC-30 and EuUHC-30 were thermally stable below 430℃ ( Figure 3 (j) The first stage of decomposition was observed between 80 and 150°C, with weight losses of 10.37% and 12.19% for UHC-30 and EuUHC-30, respectively, corresponding to the loss of solvent molecules. The UHC-30 and EuUHC-30 frameworks collapsed above 430°C.

[0044] (2) Optical properties of EuUHC-30

[0045] The solid-phase and aqueous-phase fluorescence spectra of synthesized UHC-30 and EuUHC-30 were studied. Three weak emission bands at 501, 594, and 635 nm were observed in the solid-state luminescence spectrum of UHC-30 ( Figure 4 (a)), which is attributed to the charge transfer from the ligand to the metal. On the other hand, the UHC-30 aqueous suspension only shows a broad emission band at 450 nm, corresponding to the π-π* transition in the 2-HTPA ligand ( Figure 4 (b)). Using Eu 3+ After post-synthetic modification, in addition to the emission band of the 2-htpa ligand, there is also Eu 3+ Characteristic emission bands of ions ( 5 D0→ 7 FJ , J = 0, 1, 2, 3, 4). It is worth noting that the 2-htpa emission band of EuUHC-30 in aqueous suspension is completely different from that in the solid state ( Figure 4 (c) and (d)). In the solid state, the emission band of 2-htpa is located at 400nm and is very weak. Therefore, EuUHC-30 shows purple-red fluorescence in the solid state. In contrast, in aqueous media, its red shift is to 450nm and is brighter than EuUHC-30. 3+ The emission at 614 nm is stronger, so a strong blue emission is observed in the aqueous phase under UV light. In addition, the fluorescence intensity of the EuUHC-30 solution remains unchanged within 7 days, and the XRD pattern shows no significant change ( Figure 2 (a) Figure 4 (e) and (f)), indicating that the fluorescence and framework structure are stable in aqueous media. In addition, no significant difference in the fluorescence spectrum of EuUHC-30 was observed in the pH range of 4-11 ( Figure 4 (g), (h), indicating that it can be used in a wide range of practical applications. These structural and fluorescence advantages enable EuUHC-30 to be developed into a fluorescence sensor.

[0046] (3) EuUHC-30 detection of ABZ and ABZSO

[0047] To investigate the sensing performance of EuUHC-30, fluorescence spectra were recorded in EuUHC-30 suspensions by adding different concentrations of ABZ and ABZSO. These two compounds affected the photoluminescence of EuUHC-30 in the same way. With increasing concentrations of ABZ and ABZSO, the photoluminescence of 2-HTPA and EuUHC-30 increased. 3+ Both emission centers of are significantly quenched, such as Figure 5 (a) and (b). The CIE chromaticity diagram is also consistent with the quenching effect ( Figure 5 (c), (d)). The sensitivity and detection limit (LOD) were calculated according to the Stern-Volmer equation:

[0048] F0 / F=1+Ksv[analyte]

[0049] where F0 and F are the fluorescence intensities of EuUHC-30 in the absence or presence of ABZ or ABZSO, respectively, Ksv represents the Stern-Volmer quenching constant, and [analyte] represents the concentration of ABZ or ABZSO. Interestingly, (F0 / F) 614 and (F0 / F) 450 The ratios showed good linear relationships with the concentrations of ABZ (0-110 μM) and ABZSO (0-90 μM), respectively. Figure 5(e), (f), (g) and (h)). The Ksv values ​​of ABZ and ABZSO are 54900M respectively. -1 and 38400M -1 , LOD values ​​were 0.104 μM and 0.130 μM, respectively (Table 1). To evaluate the response time, the fluorescence intensity of EuUHC-30 at 450 nm and 614 nm was recorded in the presence of ABZ or ABZSO. Figure 5 As shown in (i) and (j), the two emission bands were effectively quenched within 1 min, demonstrating their rapid responses to the two analytes and realizing the possibility of real-time monitoring of ABZ and ABZSO.

[0050] Table 1. Linear equations, Ksv, and LOD obtained from different fluorescence emission centers of ABZ and ABZSO, respectively.

[0051]

[0052]

[0053] Due to the complexity of real samples, in addition to high sensitivity and fast response, high selectivity and good anti-interference ability are prerequisites for fluorescence sensors. To examine the detection of ABZ and ABZSO in real samples, selectivity and anti-interference experiments were conducted in the presence of six common veterinary drugs and potential substances (including some metal ions and amino acids) in pig kidney and milk samples. Figure 6 As shown in (a) and (b), in the presence of carbendazim, tryptophan, methionine, VC, fructose, glucose, chloramphenicol, lincomycin, ivermectin, erythromycin, oxytetracycline, Na + and Ca 2+ In the presence of , the fluorescence intensity of EuUHC-30 did not change significantly; while benomyl, fenbendazole, lysine, leucine, valine, proline, avermectin and K + The addition of ABZ and ABZSO significantly reduced the fluorescence intensity, showing its high selectivity. In addition, ABZ and ABZSO were added to the mixture of the above substances and EuUHC-30, and the fluorescence intensity at 450nm and 614nm was recorded. By adding ABZ and ABZSO, the fluorescence of the mixture was effectively quenched ( Figure 6 (c), (d), indicating that the probe has good anti-interference ability for ABZ and ABZSO.

[0054] (4) Fluorescence quenching mechanism

[0055] In order to better understand the quenching effect of ABZ and ABZSO, the possible quenching mechanisms were investigated. Figure 7As shown in (a), the PXRD pattern of EuUHC-30 remains unchanged after the detection of ABZ and ABZSO, indicating that the quenching process is not associated with the collapse of the structural framework. XPS spectroscopy was further performed to investigate the interaction between EuUHC-30 and ABZ or ABZSO. Figure 7 (b) shows that the ABZ and ABZSO molecules change after coordination with EuUHC-30. In addition, the binding energy of Eu 3d also changes ( Figure 7 (c)). XPS results show that the nitrogen atoms of ABZ and ABZSO are closely related to the Eu atoms in EuUHC-30. 3+ Ion coordination (Table 2). UV-vis spectral analysis showed that most of the absorption bands of the analytes were related to betc 4- Ligand overlap ( Figure 7 (d)). The possible mechanism is that in the presence of ABZ or ABZSO, the absorption of ABZ or ABZSO will be related to the betc 4- ligand competition, which greatly reduces betc 4- to Eu 3+ energy transfer efficiency, resulting in luminescence quenching (Figure (e), (f)).

[0056] Table 2. XPS binding energy summary

[0057]

[0058]

[0059] (5) Quantification of ABZ and ABZSO in real samples

[0060] Due to the excellent sensing performance of EuUHC-30 for ABZ and ABZSO, its practical application in milk and pig kidney samples was evaluated using the standard addition recovery method. After adding the pretreatment solution, the fluorescence intensity of EuUHC-30 did not change significantly ( Figure 8 ), indicating that ABZ and ABZSO are absent or present below the LOD in authentic samples. As shown in Table 3, the recoveries of ABZ in milk ranged from 87.67% to 102.33%, those in porcine kidney ranged from 99.33% to 105.50%, those in milk ranged from 101.00% to 113.54%, and those in porcine kidney ranged from 92.00% to 107.17%. These results are consistent with those of the HPLC analysis, demonstrating that the EuUHC-30-based fluorescence detection method is reliable for the quantification of ABZ and ABZSO in milk and porcine kidney samples.

[0061] Table 3. Quantification of ABZ / ABZSO in milk and pig kidney samples by fluorescence and HPLC methods.

[0062]

[0063] (6) Color quantitative detection of ABZ and ABZSO using smartphone imaging

[0064] Although methods for the quantitative detection of ABZ and ABZSO have been reported, a visual online detection method for ABZ and ABZSO has not yet been reported. Because the change in fluorescence color can be seen by the naked eye, fluorescent test strips were first developed for the rapid and convenient detection of ABZ and ABZSO. Fluorescent paper sensors were prepared using ordinary filter paper, cut into 0.5 cm × 3.0 cm pieces, and coated with a suspension of 0.5 mg / mL EuUHC-30 reacted with standard solutions of ABZ (0, 0.5, 1, 3, 5, 10, 15, 30, 40, 50, 70, 90, and 110 μM) and ABZSO (0, 1, 5, 1, 10, 20, 30, 50, 50, 90, and 100 μM). Figure 9 showed that the naked eye can observe color changes in fluorescent images taken under UV light.

[0065] In order to achieve more sensitive and accurate portable detection of ABZ and ABZSO, fluorescent paper strips were combined with smartphone imaging using RGB color values, which can reduce errors caused by individual differences in color perception and is more sensitive and accurate than the human eye. A freely available RGB color value application was installed on the smartphone. Under UV light, a fluorescence image of the test strip was taken using the rear camera in the presence of ABZ (0-110μM) and ABZSO (0-110μM). The RGB values ​​of the fluorescence image were then analyzed using the installed RGB application. The R / B value of the test strip was compared with the ABZ (R 2 =0.9957) and ABZSO(R 2 =0.9917) showed a good linear relationship in the concentration range of 0-110 μM, the LOD value of ABZ was 0.36 μM, and the LOD of ABZSO was 0.17 μM ( Figure 10 ). Smartphone imaging was used to detect ABZ and ABZSO in real samples using a spike-in recovery method to evaluate the reliability of the sensor. As shown in Table 4, the results showed good recoveries and satisfactory RSD values, indicating that smartphone imaging can be used to monitor ABZ and ABZSO in milk and porcine kidney. The present invention provides a portable, low-cost, visible, and rapid method for the on-site quantification of ABZ and ABZSO in animal-derived foods. Furthermore, this is the first visual quantitative detection method for ABZ and ABZSO using smartphone imaging in real food samples.

[0066] Table 4. Quantification of ABZ and ABZSO in milk and pig kidney samples using a smartphone platform.

[0067]

[0068]

Claims

1. Application of the rare earth metal organic framework material EuUHC-30 in the detection of ABZ and / or ABZSO, characterized by: The rare earth metal organic framework material EuUHC-30 is composed of UHC-30 in Eu 3+ The UHC-30 is obtained by reacting ZrCl4, 1,2,4,5-benzenetetracarboxylic acid and 2-hydroxyterephthalic acid in a molar ratio of 2.00:2.8:1.2 in water.

2. A method for detecting ABZ and / or ABZSO, characterized in that: The method comprises the following steps: adding a detection sample to the aqueous suspension of EuUHC-30 described in claim 1, detecting the change of its fluorescence intensity at 450 nm or 614 nm, and realizing the detection of ABZ and / or ABZSO.

3. The method for detecting ABZ and / or ABZSO according to claim 2, characterized in that: The test sample comes from animal-derived food.

4. Use of the rare earth metal organic framework material EuUHC-30 described in claim 1 in the preparation of products for detecting ABZ and / or ABZSO.

5. A system for detecting ABZ and / or ABZSO, characterized by: The invention comprises a test paper and a color recognition device; the test paper is a test paper impregnated or coated with the suspension of EuUHC-30 described in claim 1.

6. The system for detecting ABZ and / or ABZSO according to claim 5, characterized in that: The color recognition device is a device installed with an RGB color value application.

7. The system for detecting ABZ and / or ABZSO according to claim 6, characterized in that: The color recognition device is a smart phone installed with an RGB color value application.

8. The system for detecting ABZ and / or ABZSO according to claim 5, characterized in that: Also included is the linear relationship between RGB values ​​and ABZ and / or ABZSO concentrations.

9. The system for detecting ABZ and / or ABZSO according to claim 8, characterized in that: The linear relationship is determined by a method comprising the following steps: coating a test paper with a suspension obtained by reacting EuUHC-30 with a standard concentration of ABZ or ABZSO, photographing the test paper using a camera under ultraviolet light, and determining a linear relationship between the RGB value of the photographed image and the concentration of ABZ and / or ABZSO.

10. A method for using the system for detecting ABZ and / or ABZSO according to any one of claims 5 to 9, characterized in that: The method comprises the following steps: adding a solution to be tested to a test paper for reaction to obtain the test paper; identifying the RGB value of the test paper under ultraviolet light using a color recognition device; and comparing the RGB value with a linear relationship between the RGB value and the concentration of ABZ and / or ABZSO to obtain the concentration of ABZ or ABZSO in the solution to be tested.

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