Phosphorescence detection method for levofloxacin in complex matrix and application of phosphorescence detection method

Abstract

According to the phosphorescence detection method for levofloxacin in the complex matrix provided by the invention, the complex matrix is a water-containing heterogeneous system, and the method comprises the following steps: adding a demulsifier A, a flocculant B and an acid C into the complex matrix, centrifuging, taking supernate, and neutralizing with alkali to obtain an extracting solution A; the demulsifier A is polyethylene oxide; the flocculant B is any one or a mixture of polymeric ferric sulfate and polymeric aluminum sulfate; boric acid and the first extracting solution are mixed, a catalyst D and a catalyst E are added into the mixture and heated, a second product is obtained, cobalt salt is selected as the catalyst D, and iodized salt is selected as the catalyst E; and exciting the product B with ultraviolet rays, and then carrying out phosphorescence detection to obtain a detection result of levofloxacin in the complex matrix. Quantitative or qualitative detection of trace levofloxacin in the complex matrix extracting solution can be achieved, the detection sensitivity is high, operation is convenient, the phenomenon is obvious, and rapid detection is facilitated.

Description

Technical Field

[0001] The present disclosure relates to the field of food safety, and particularly to a phosphorescence detection method for levofloxacin in complex matrices and its application. Background Art

[0002] Levofloxacin is a broad-spectrum quinolone antibacterial drug, which is widely used in the fields of treating infections, aquaculture, etc. According to the list of illegal food additives released by the former Ministry of Health, quinolone antibiotics may be illegally added to spicy hot pot. The residue of quinolone antibiotics in the human body can cause liver and kidney toxicity and produce drug resistance, endangering human health. Therefore, it is necessary to develop a rapid detection method for quinolone antibiotics. According to case and pharmacokinetic data conversion, the concentration of levofloxacin in the matrix needs to be greater than 1 mg / mL to exert the anti-diarrhea treatment effect. Spicy hot pot is a suspended emulsion containing a large amount of substances such as proteins, seasonings, and oils. The liquid-liquid extraction method is difficult to enrich levofloxacin with good water solubility, and usually, the solid-phase extraction method needs to be used in combination with large-scale instruments for detection.

[0003] Currently, some literatures have studied the phosphorescence properties of materials based on levofloxacin. For example, in Chinese Patent Application CN119505893A, it was studied that levofloxacin and acid generated carbon quantum dots with phosphorescence properties through a hydrothermal method, where the minimum mass ratio of levofloxacin to acid was 1:10. In Chinese Patent Application CN112500740A, it was studied that levofloxacin generated phosphorescent carbon dots through a solvothermal reaction, where the minimum mass-to-volume ratio of levofloxacin to the solvent was 1:1000. In Chinese Patent Application CN118620614A, it was studied that levofloxacin was mixed with raw materials such as boric acid to generate phosphorescent carbon dots, where the minimum mass ratio of levofloxacin to acid was 1:300. In these studies, it was all considered that levofloxacin produced phosphorescence by generating carbon quantum dots after the reaction. At the same time, the studies on the concentration-dependent relationship between levofloxacin and phosphorescence intensity were lacking in these studies, and the phosphorescence conditions when the mass of levofloxacin in the system was less than one-thousandth were lacking, and the detection effect for trace levofloxacin was unknown.

[0004] The phosphorescence phenomenon is a molecular luminescence phenomenon associated with fluorescence. Phosphorescence has a longer lifetime and can be observed with the naked eye, thus avoiding the interference of fluorescent substances in the matrix. Using phosphorescence detection has good sensitivity, selectivity, and can effectively reduce background interference. Levofloxacin has a conjugated structure basis for generating phosphorescence, but it is difficult to generate long-lived room-temperature phosphorescence due to the presence of a rotatable diazine ring in the molecule. Boric acid can stabilize the highly conjugated molecular skeleton of levofloxacin through the formation of mixed anhydrides and hydrogen bond interactions, and isolate the quenching of phosphorescence by water and oxygen, thereby generating room-temperature long-lived phosphorescence.

[0005] The above information disclosed in the background art section is only used to enhance the understanding of the background of the present invention, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0007] To this end, the present invention provides a method for phosphorescence detection of levofloxacin in a complex matrix and its application. By reducing the interference of the inner filter effect on phosphorescence detection, rapid detection of trace levofloxacin can be achieved, and the detection sensitivity is high, the operation is convenient, and the phenomenon is obvious.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for phosphorescence detection of levofloxacin in a complex matrix according to the first aspect of the present invention, wherein the complex matrix is a water-containing heterogeneous system, and the phosphorescence detection method includes:

[0010] Adding a demulsifier A, a flocculant B and an acid C to the complex matrix, centrifuging to obtain the supernatant and neutralizing it with an alkali to obtain an extraction solution A; the demulsifier A is selected from polyethylene oxide, and its concentration range is 0.01 g / L to 10 g / L; the flocculant B is selected from any one or a mixture of ferric polysulfate and aluminum polysulfate; the concentration range of the acid C is 1 g / L to 1000 g / L; the mass ratio of the complex matrix, the demulsifier A, the flocculant B and the acid C is 1:0.1:0.01 - 0.2:0.1;

[0011] After mixing boric acid with the extraction solution A, adding a catalyst D and a catalyst E thereto and heating to obtain a product B, the catalyst D is selected from cobalt salts, and the catalyst E is selected from iodine salts, and the mass ratio of boric acid, the extraction solution A, the catalyst D and the catalyst E is 1:0.5 - 100:0.005‰ - 5‰:0.005‰ - 5‰;

[0012] Phosphorescence detection is carried out on the product B after being excited by ultraviolet light to obtain the detection result of levofloxacin in the complex matrix.

[0013] In some embodiments, the acid C is selected from any one or a mixture of formic acid, acetic acid and hydrochloric acid.

[0014] In some embodiments, the catalyst D is selected from any one or a mixture of cobalt chloride, cobalt nitrate and cobalt sulfate.

[0015] In some embodiments, the catalyst E is selected from any one or a mixture of sodium iodide and potassium iodide.

[0016] In some embodiments, the temperature used during heating is 150°C to 300°C.

[0017] In some embodiments, when ultraviolet excitation is performed on the product B, the excitation light wavelength used is 340 nm to 400 nm, and the time for detecting phosphorescence is 0.1 s to 5 s.

[0018] In some embodiments, the phosphorescence detection method further includes:

[0019] Utilizing the linear relationship between the phosphorescence intensity and the concentration of levofloxacin, the concentration of levofloxacin in the complex matrix is quantitatively or qualitatively detected; when used for quantitative detection, the linear detection range of levofloxacin is 0.001 mg / mL to 1 mg / mL, and the detection limit is 0.0004 mg / mL.

[0020] In some embodiments, when the complex matrix contains levofloxacin, the phosphorescence is yellow-green phosphorescence or the phosphorescence intensity at a detection wavelength of 500 nm to 550 nm.

[0021] An application of the phosphorescence detection method according to any embodiment of the first aspect of the present invention in the detection of trace levofloxacin in foods having an aqueous heterogeneous system according to the second aspect of the present invention.

[0022] In some embodiments, the food is spicy hot pot.

[0023] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0024] The present invention uses polyferric sulfate and / or polyaluminum sulfate as flocculants, polyethylene oxide as a demulsifier, mixes them with an acid solution, and extracts by centrifugation, developing a pretreatment method that can effectively solve the problem of matrix turbidity caused by the addition of milk powder, has a good purification effect on complex matrices, clarifies the complex matrices, avoids the inner filter effect from obscuring phosphorescence, and does not adsorb levofloxacin.

[0025] The present invention utilizes the catalysis and phosphorescence enhancement of cobalt salts and iodide salts on the reaction between boric acid and levofloxacin to strengthen the phosphorescence phenomenon of the reaction product.

[0026] In summary, the present invention can be applied to the quantitative or qualitative detection of trace levofloxacin in complex matrix extracts, and has high detection sensitivity, convenient operation, obvious phenomena, and is conducive to rapid detection. Description of the Drawings

[0027] Figure 1 It is a phosphorescence schematic diagram of the reaction product of boric acid and levofloxacin with a content of 1 mg / mL after being excited by 365 nm ultraviolet light;

[0028] Figure 2It is the phosphorescence spectrum measured by a spectrometer at 365 nm for the reaction product of boric acid and levofloxacin with a content of 1 mg / mL.

[0029] Figure 3 It is a graph showing the functional relationship between the phosphorescence intensity detected by the detection method provided in Example 1 of the present invention and the concentration of levofloxacin;

[0030] Figure 4 In it, a, b, and c are respectively graphs showing the relationship between different purifying agent concentrations and the purification effect of the spicy hot pot matrix in Example 1;

[0031] Figure 5 It is a comparison graph of the effects without adding cobalt chloride catalyst and using cobalt chloride catalyst in Example 1 of the present invention;

[0032] Figure 6 It is a comparison graph of the effects without adding sodium iodide catalyst and using sodium iodide catalyst in Example 1 of the present invention;

[0033] Figure 7 It is the nuclear magnetic resonance hydrogen spectrum before and after the reaction in step S2 of Example 1 of the present invention;

[0034] Figure 8 It is the infrared spectrum before and after the reaction in step S2 of Example 1 of the present invention;

[0035] Figure 9 It is the enlarged scanning electron microscope image of reaction product B obtained in step S2 of Example 1 of the present invention.

[0036] Figure 10 In it, a, b, c, and d are respectively graphs showing the influence of iodine content, cobalt content, reaction temperature, and the mass ratio of the extraction solution to boric acid on the phosphorescence situation. Detailed implementation manners

[0037] The present application will be further described in detail below in conjunction with the accompanying drawings through specific implementation manners. Similar elements in different implementation manners use related similar element numbers. In the following implementation manners, many detailed descriptions are provided to enable a better understanding of the present application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification to avoid inundating the core part of the present application with excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and general technical knowledge in the field.

[0038] In addition, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can also be reordered or adjusted in a manner obvious to those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment and do not mean a necessary sequence, unless it is stated that a certain sequence must be followed.

[0039] In the scope disclosed in this application, the endpoints and any values of the scope are not limited to the exact scope or value. These scopes or values should be understood to include values close to these scopes or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this application.

[0040] A method for phosphorescence detection of levofloxacin in a complex matrix provided by an embodiment of the first aspect of the present invention includes:

[0041] Step S1: Add demulsifier A, flocculant B, and acid C to the complex matrix, centrifuge to obtain the supernatant and neutralize it with an alkali to obtain extract A; wherein, the complex matrix is an aqueous heterogeneous system such as an emulsion or a suspension; demulsifier A is selected from polyethylene oxide, and its concentration range is 0.01 g / L to 10 g / L; flocculant B is selected from any one or a mixture of polyferric sulfate and polyaluminum sulfate; the concentration range of acid C is 1 g / L to 1000 g / L; the mass ratio of the complex matrix, demulsifier A, flocculant B, and acid C is 1:0.1:0.01 - 0.2:0.1;

[0042] Step S2: After mixing boric acid with extract A, add catalyst D and catalyst E thereto and heat to obtain product B, wherein catalyst D is selected from cobalt salts, catalyst E is selected from iodine salts, and the mass ratio of boric acid, extract A, catalyst D, and catalyst E is 1:0.5 - 100:0.005‰ - 5‰:0.005‰ - 5‰;

[0043] Step S3: After exciting product B with ultraviolet light, perform phosphorescence detection to obtain the detection result of levofloxacin in the complex matrix.

[0044] In some embodiments, step S1 is carried out at room temperature. Except for flocculant B being solid, the rest of the raw materials are liquid.

[0045] In some embodiments, in step S1, acid C is selected from any one or a mixture of formic acid, acetic acid, and hydrochloric acid.

[0046] It can be understood that step S1 is a pretreatment step for the complex matrix. The complex matrix targeted by the present invention is a suspension emulsion formed by adding milk powder. Step S1 uses polyethylene oxide as a demulsifier, and polymeric ferric sulfate and / or polymeric aluminum sulfate as flocculants and acts together with an acid, which has a good purification effect on the complex matrix, so that the complex matrix is clarified to avoid the inner filter effect from obscuring phosphorescence and will not adsorb levofloxacin. The purification effect of step S1 is good and the operation is convenient.

[0047] In some embodiments, in step S2, except that extraction liquid A is in a liquid state, the rest of the raw materials are in a solid state.

[0048] In some embodiments, in step S2, catalyst D is selected from any one or a mixture of cobalt chloride, cobalt nitrate, and cobalt sulfate.

[0049] In some embodiments, in step S2, catalyst E is selected from any one or a mixture of sodium iodide and potassium iodide.

[0050] In some embodiments, in step S2, the temperature used during heating should be such that boric acid reaches its melting point and fully coats the levofloxacin molecules, preferably 150°C to 300°C; the heating time is preferably 5 min to 300 min.

[0051] It can be understood that step S2 uses a cobalt salt as a catalyst to promote the reaction of boric acid with the carboxyl group of levofloxacin to stabilize levofloxacin in extraction liquid A, and the heavy atom effect provided by the iodide salt acts together to enhance the phosphorescence of the reaction product. After the strengthening treatment of step S2, it can be used for the rapid phosphorescence detection of trace levofloxacin in the subsequent steps.

[0052] In some embodiments, in step S3, when ultraviolet excitation is performed on product B, the excitation light wavelength used is 340 nm to 400 nm, and the time for detecting phosphorescence is 0.1 s to 5 s.

[0053] In some embodiments, step S3 further includes using the linear relationship between the phosphorescence intensity and the concentration of levofloxacin to perform quantitative or qualitative detection of the concentration of levofloxacin in the complex matrix; when used for quantitative detection, the linear detection range of levofloxacin is 0.001 mg / mL to 1 mg / mL, and the detection limit is 0.0004 mg / mL.

[0054] Furthermore, when levofloxacin is contained in the complex matrix, the phosphorescence is yellow-green phosphorescence or the phosphorescence intensity at a detection wavelength of 500 nm to 550 nm.

[0055] The second aspect of the present invention provides an application of the above detection method in the detection of trace levofloxacin in foods with an aqueous heterogeneous system. Specifically, when using this food as a complex matrix and detecting it by the method provided in the first aspect of the present invention, if product B emits yellow-green phosphorescence when excited by ultraviolet light, it indicates that levofloxacin is contained in this food; otherwise, it indicates that levofloxacin is not contained.

[0056] Further, when it is detected that levofloxacin is contained in the food, the concentration of levofloxacin in the food is determined according to the phosphorescence intensity at a detection wavelength of 500 nm to 550 nm.

[0057] Further, the food is spicy hot pot.

[0058] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0059] Example 1:

[0060] In this example, the matrix of spicy hot pot was pretreated and subjected to enhanced treatment of levofloxacin assisted by boric acid, followed by phosphorescence detection. Specifically, it was completed according to the following steps:

[0061] Step S1, pretreatment of the complex matrix: At room temperature, take 1 g of the spicy hot pot matrix, add 0.1 g of polyethylene oxide (concentration: 10 g / L), 0.05 g of polymeric ferric sulfate, and 0.1 g of formic acid (concentration: 1000 g / L). Centrifuge and take the supernatant, and neutralize it with an alkali to obtain extract A.

[0062] Step S2, enhanced treatment of levofloxacin assisted by boric acid: Take 1 g of boric acid, add 1 g of extract A, add 0.005 g of cobalt chloride and 0.000005 g of sodium iodide, and heat at 200 °C for 180 min to obtain product B.

[0063] Step S3, phosphorescence detection: After product B is excited by 365 nm ultraviolet light, detect the phosphorescence intensity after 0.5 s. Refer to Figure 1 , it can be seen that the matrix of spicy hot pot without levofloxacin also has a bright blue background fluorescence from the fluorescence perspective, while the matrix of spicy hot pot added with 1 mg / mL levofloxacin can emit yellow phosphorescence after the ultraviolet lamp is turned off. The intensity of this yellow phosphorescence gradually weakens with the increase of the detection time and almost disappears after 1.25 s. Refer to Figure 2 , it can be seen that the phosphorescence emission wavelength of levofloxacin in product B is 534 nm. Subsequently, the detected phosphorescence intensity and the levofloxacin concentration were linearly fitted. Refer to Figure 3 (It should be noted that since Figure 3The horizontal axis in [it] uses a logarithmic axis, making the fitting curve exponential. Actually, it satisfies a linear relationship. It can be found that the detection method in this embodiment is linear within the levofloxacin concentration range of 0.001 mg / mL to 1 mg / mL and satisfies the relational expression: y = 14655.43x + 232859.79, where x is the levofloxacin concentration and y is the phosphorescence intensity, and the fitting degree R 2 = 0.999. The detection limit of the method in this embodiment is 0.0004 mg / mL.

[0064] The principle of this embodiment is as follows: Figure 4 In [it], a, b, and c respectively show the influence of the concentrations of various purifying agents (i.e., demulsifier - polyethylene oxide, flocculant - polyferric sulfate, formic acid) used in step S1 on the purification effect of the spicy hot pot matrix (reflected by the relationship between the absorbance / turbidity of the spicy hot pot matrix). By using purifying agents for different purposes in combination, a better purification effect can be achieved. As for the detection method, cobalt ions, as Lewis acids, catalyze the reaction between boric acid and levofloxacin. See Figure 5 , where the levofloxacin content is 0.1 mg / mL; and iodide ions enhance phosphorescence through the heavy atom effect. See Figure 6 , where the levofloxacin content is 0.1 mg / mL. After adding sodium iodide, compared with when sodium iodide is not added, the phosphorescence intensity of levofloxacin is enhanced. See Figure 7 , by comparing the nuclear magnetic resonance hydrogen spectra before and after the reaction in step S2, where the green line is levofloxacin before the reaction in step S2 and the red line is levofloxacin after reacting with boric acid, it can be seen that the chemical shifts at 3.45, 2.67, and 2.42, which belong to the hydrogens on the diazine ring and the methyl group linked to it, have changed, while the chemical shifts of other hydrogens have not changed. From this, it can be known that the skeletal structure of levofloxacin is relatively complete, while the chemical shifts of the diazine ring and the methyl group on it are greatly affected. It can be seen that boric acid interacts with this part that can rotate freely, making it stable, thereby reducing the non-radiative transition energy loss caused by molecular vibration and rotation. See Figure 8 , by comparing the infrared spectra before and after the reaction in step S2, where the solid line is the infrared spectrum of levofloxacin, it can be seen that there is an OH absorption of the carboxyl group at 3264 cm -1 -1, and this absorption almost disappears after the reaction. From this, it can be known that the carboxyl group belonging to levofloxacin disappears due to the reaction with boric acid. And through the scanning electron micrograph of the reaction product ( Figure 9 ), it can be seen that its surface is relatively smooth, only having some cracks and not having nanostructures such as carbon dots. Therefore, at lower concentrations, levofloxacin will not further react to form other phosphorescent substances, which is the basis for quantitatively detecting the levofloxacin concentration.

[0065] Example 2:

[0066] In this example, the spicy hot pot matrix is pretreated and then subjected to phosphorescence detection after levofloxacin enhanced treatment assisted by boric acid. Specifically, it is completed according to the following steps:

[0067] Step S1. Pretreatment of complex matrix: Take 1 g of spicy hot pot matrix, add 0.1 g of polyethylene oxide (concentration: 0.01 g / L), 0.02 g of polymeric ferric sulfate, and 0.1 g of hydrochloric acid (concentration: 500 g / L), centrifuge to obtain the supernatant and neutralize it with alkali to obtain extract A.

[0068] Step S2. Levofloxacin enhanced treatment assisted by boric acid: Take 1 g of boric acid, add 50 g of extract A, add 0.0025 g of cobalt sulfate and 0.0025 g of potassium iodide, and heat at 225 °C for 150 min to obtain product B.

[0069] Step S3. Phosphorescence detection: After exciting product B with ultraviolet light at 370 nm, detect the phosphorescence intensity after 2.5 s.

[0070] Example 3:

[0071] In this example, the spicy hot pot matrix is pretreated and then subjected to phosphorescence detection after levofloxacin enhanced treatment assisted by boric acid. Specifically, it is completed according to the following steps:

[0072] Step S1. Pretreatment of complex matrix: Take 1 g of spicy hot pot matrix, add 0.1 g of polyethylene oxide (concentration: 0.1 g / L), 0.01 g of polymeric aluminum sulfate, and 0.2 mL of acetic acid (concentration: 1000 g / L), centrifuge to obtain the supernatant and neutralize it with alkali to obtain extract A.

[0073] Step S2. Levofloxacin enhanced treatment assisted by boric acid: Take 1 g of boric acid, add 0.5 g of extract A, add 0.005 g of cobalt nitrate and 0.005 g of sodium iodide, and heat at 300 °C for 5 min to obtain product B.

[0074] Step S3. Phosphorescence detection: After exciting product B with ultraviolet light at 400 nm, detect the phosphorescence intensity after 0.1 s.

[0075] Example 4:

[0076] In this example, the spicy hot pot matrix is pretreated and then subjected to phosphorescence detection after levofloxacin enhanced treatment assisted by boric acid. Specifically, it is completed according to the following steps:

[0077] Step S1. Pretreatment of complex matrix: Take 1 g of spicy hot pot matrix, add 0.1 g of polyethylene oxide (concentration: 1 g / L), 0.1 g of polymeric aluminum sulfate, and 0.1 g of formic acid (concentration: 1 g / L), centrifuge to obtain the supernatant and neutralize it with alkali to obtain extract A.

[0078] Step S2: Levofloxacin enhanced treatment assisted by boric acid: Take 1 g of boric acid, add it to 100 g of extract A, add 0.000005 g of cobalt sulfate and 0.000005 g of potassium iodide, and heat at 150 °C for 300 min to obtain product B.

[0079] Step S3: Phosphorescence detection: After exciting product B with 340 nm ultraviolet light, detect the phosphorescence intensity after 5 s.

[0080] Example 5:

[0081] In this example, the pretreatment of the spicy hot pot matrix and the levofloxacin enhanced treatment assisted by boric acid are carried out, and then phosphorescence detection is carried out. Specifically, it is completed according to the following steps:

[0082] Step S1: Pretreatment of complex matrix: Take 1 g of spicy hot pot matrix, add 0.1 g of polyethylene oxide (concentration: 5 g / L), 0.03 g of polymeric ferric sulfate and 0.1 g of acetic acid (concentration: 20 g / L), centrifuge to obtain the supernatant and neutralize it with alkali to obtain extract A.

[0083] Step S2: Levofloxacin enhanced treatment assisted by boric acid: Take 1 g of boric acid, add it to 25 g of extract A, add 0.001 g of cobalt chloride and 0.001 g of sodium iodide, and heat at 275 °C for 75 min to obtain product B.

[0084] Step S3: Phosphorescence detection: After exciting product B with 380 nm ultraviolet light, detect the phosphorescence intensity after 1.5 s.

[0085] See Figure 10 , which are the experimental data for single-factor optimization of the raw material parameters in the detection method of the present invention. Among them, a represents the influence of the mass ratio of boric acid to iodide salt on the relative phosphorescence intensity of the product. It can be seen that the product has strong phosphorescence in the range of 0.005‰ - 5‰, and is higher than the group without adding iodide salt. b represents the influence of the mass ratio of boric acid to cobalt salt on the relative phosphorescence intensity of the product. It can be seen that the product has strong phosphorescence in the range of 0.005‰ - 5‰, and is higher than the group without adding cobalt salt. c represents the influence of the reaction temperature on the relative phosphorescence intensity of the product. It can be seen that the product has strong phosphorescence in the range of 150 °C - 300 °C. d represents the influence of the mass ratio of boric acid to extract on the relative phosphorescence intensity of the product. It can be seen that good effects are obtained in the range of 0.5 - 100.

[0086] The technical solution of the present invention is not limited to the specific embodiments listed above, and should also include various applications of mixing boric acid with iodide salt and cobalt salt for the detection of trace levofloxacin.

[0087] In summary, the present invention can be applied to the quantitative or qualitative detection of trace levofloxacin in complex matrix extracts, and has high detection sensitivity, convenient operation, obvious phenomena, and is conducive to rapid detection.

[0088] The above has described the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention.

Claims

1. A method for phosphorescence detection of levofloxacin in a complex matrix, characterized in that, The complex matrix is an aqueous heterogeneous system, and the phosphorescence detection method includes: Adding a demulsifier A, a flocculant B, and an acid C to the complex matrix, centrifuging to obtain the supernatant and neutralizing it with an alkali to obtain extract A; the demulsifier A is selected from polyethylene oxide, and its concentration range is 0.01 g / L to 10 g / L; the flocculant B is selected from any one or a mixture of polyferric sulfate and polyaluminum sulfate; the concentration range of the acid C is 1 g / L to 1000 g / L; the mass ratio of the complex matrix, the demulsifier A, the flocculant B, and the acid C is 1:0.1:0.01 - 0.2:0.1; After mixing boric acid with the extract A, adding a catalyst D and a catalyst E thereto and heating to obtain product B, the catalyst D is selected from cobalt salts, and the catalyst E is selected from iodine salts, and the mass ratio of boric acid, extract A, catalyst D, and catalyst E is 1:0.5 - 100:0.005‰ - 5‰:0.005‰ - 5‰; After exciting the product B with ultraviolet light, performing phosphorescence detection to obtain the detection result of levofloxacin in the complex matrix.

2. The phosphorescence detection method according to claim 1, wherein The acid C is selected from any one or a mixture of formic acid, acetic acid, and hydrochloric acid.

3. The phosphorescence detection method according to claim 1, characterized in that, The catalyst D is selected from any one or a mixture of cobalt chloride, cobalt nitrate, and cobalt sulfate.

4. The phosphorescence detection method according to claim 1, wherein The catalyst E is selected from any one or a mixture of sodium iodide and potassium iodide.

5. The phosphorescence detection method according to claim 1, characterized in that, The temperature used during heating is 150°C to 300°C.

6. The phosphorescence detection method according to claim 1, wherein When exciting the product B with ultraviolet light, the excitation light wavelength used is 340 nm to 400 nm, and the time for detecting phosphorescence is 0.1 s to 5 s.

7. The phosphorescence detection method according to claim 1, wherein The phosphorescence detection method further includes: Using the linear relationship between the phosphorescence intensity and the concentration of levofloxacin to quantitatively or qualitatively detect the concentration of levofloxacin in the complex matrix; when used for quantitative detection, the linear detection range of levofloxacin is 0.001 mg / mL to 1 mg / mL, and the detection limit is 0.0004 mg / mL.

8. The phosphorescence detection method according to claim 7, wherein When the complex matrix contains levofloxacin, the phosphorescence is yellow-green phosphorescence or the phosphorescence intensity at a detection wavelength of 500 nm to 550 nm.

9. An application of the phosphorescence detection method according to any one of claims 1 to 8 in the detection of trace levofloxacin in foods having an aqueous heterogeneous system.

10. The application according to claim 9, wherein The food is spicy hot pot.

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