A rapid detection method for lomefloxacin based on fluorescent carbon dots
By preparing nitrogen-doped fluorescent carbon dots and applying them to the detection of lomefloxacin, the problems of insufficient sensitivity and specificity in existing detection methods have been solved, achieving efficient and simple lomefloxacin detection, which is applicable to the detection of lomefloxacin raw materials, its preparations, and veterinary drug residues.
Patent Information
- Application Number
- CN202310580963.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-22
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2043-05-22
AI Technical Summary
There is a lack of effective methods for detecting lomefloxacin in the current technology, especially in terms of sensitivity and specificity, and traditional organic dye probes have problems with photobleaching and toxicity.
Fluorescent carbon dots were used as the detection tool. Nitrogen-doped carbon dots were prepared by hydrothermal method. High fluorescence performance carbon dots were prepared by combining citric acid and tyrosine as raw materials. Based on this, a rapid detection method for lomefloxacin was constructed. The emission intensity was measured by fluorescence spectrophotometer and linear regression was performed.
This invention provides a highly sensitive, specific, and easy-to-operate method for the detection of lomefloxacin, which is suitable for determining the drug concentration in lomefloxacin raw materials and their preparations as well as veterinary drug residues. The preparation process is environmentally friendly and economical, with a low detection limit and high accuracy.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of drug detection technology, specifically to a rapid detection method for lomefloxacin based on fluorescent carbon dots. Background Technology
[0002] Carbon quantum dots (CQDs) are a class of novel, spherical, stable luminescent small carbon nanoparticles with a particle size of less than 10 nanometers. They were first discovered in 2004 during the purification of single-walled carbon nanotubes. Due to their excellent photostability, small size, highly tunable photoluminescence, excellent biocompatibility, electrochemiluminescence, excellent multiphoton excitation (upconversion), good solubility, high quantum yield, surface functional groups, and low toxicity, CQDs have wide applications in bioimaging, biosensing, biopharmaceuticals, disease detection, optoelectronics, sensors, and catalysis. In recent years, doping with heteroatoms to improve the fluorescence performance of CQDs has become a research hotspot, because the structural changes caused by doping can effectively alter the essential properties of CQDs. Nitrogen doping is a common doping method.
[0003] Compared to traditional organic dye-based sensing probes, carbon quantum dots exhibit superior properties as fluorophores due to the photobleaching and toxicity issues associated with the former. The presence of functional groups such as hydroxyl, carboxyl, carbonyl, and epoxy groups on their surface endows them with water solubility. Furthermore, these groups pave the way for surface functionalization of quantum dots and provide selectivity for target analytes. Currently, no applications of carbon dots for lomefloxacin detection have been reported. Summary of the Invention
[0004] To address the aforementioned technical problems, the present invention aims to provide a rapid detection method for lomefloxacin based on fluorescent carbon dots, offering a new pathway for lomefloxacin detection. This method boasts advantages such as convenient construction, high sensitivity, good specificity, and ease of use, and can be applied to the determination of drug concentration in lomefloxacin raw materials and their preparations, as well as in veterinary drug residues.
[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a rapid detection method for lomefloxacin based on fluorescent carbon dots is provided, which applies fluorescent carbon dots to the detection of lomefloxacin drug concentration.
[0006] A rapid detection method for lomefloxacin based on fluorescent carbon dots includes the following steps:
[0007] (1) Prepare a carbon dot solution by mixing the above fluorescent carbon dots with water, and then add lomefloxacin standard solutions of different concentrations. Use 395nm as the excitation wavelength and measure the emission intensity at 485nm wavelength with a fluorescence spectrophotometer. Use the least squares method to perform linear regression on the change in emission intensity and lomefloxacin concentration to obtain the standard curve equation.
[0008] (2) Calculate the fluorescence intensity change value of the sample to be tested according to y=F-F0, and then substitute the fluorescence intensity change value obtained from the measurement of the sample to be tested into the standard curve to calculate the concentration of lomefloxacin to be tested.
[0009] Further, in step (1), fluorescent carbon dots are prepared by the following method: using citric acid as carbon source and tyrosine as nitrogen source, they are ultrasonically mixed with deionized water, and then hydrothermally reacted at 140-240℃ for 2-8 hours. After filtration, dialysis and freeze-drying, fluorescent carbon dots are obtained.
[0010] Furthermore, the mass ratio of citric acid to tyrosine is 1:3-3:1.
[0011] Furthermore, the mass-to-volume ratio of citric acid to deionized water is 0.5 g: 10-25 mL.
[0012] Furthermore, after filtration through a 0.22μm microporous membrane, the molecular weight cutoff of the dialysis bag during dialysis is 1000-5000 Da, and the dialysis time is 12-48 hours.
[0013] Furthermore, in step (1), the solubility of the carbon dot solution is 0.01-2.00 mg / mL.
[0014] Furthermore, in step (2), the volume ratio of the carbon dot solution to the lomefloxacin standard solution is 1:0.5-5.
[0015] Furthermore, in step (2), the volume ratio of the carbon dot solution to the lomefloxacin standard solution is 1:1.
[0016] Furthermore, in step (2), F represents the fluorescence intensity of the carbon dots when lomefloxacin is added, and F0 represents the fluorescence intensity of the carbon dots when lomefloxacin is not added.
[0017] The present invention has the following beneficial effects:
[0018] 1. This invention applies fluorescent carbon dots to the detection of lomefloxacin drug concentration, providing a new pathway for the detection of lomefloxacin. It has advantages such as convenient construction, high sensitivity, good specificity, and ease of use. It can be applied to the determination of drug concentration in lomefloxacin raw materials and their preparations, as well as in veterinary drug residues.
[0019] 2. This invention uses citric acid as the carbon source, which is abundant, inexpensive, and readily available. Simultaneously, it employs water as the reaction solvent, employing a one-step hydrothermal synthesis method. The process is simple, environmentally friendly, economical, and efficient, possessing significant social importance. The resulting nitrogen-doped carbon dots exhibit excellent fluorescence properties and superior water solubility. Furthermore, the carbon dot quantum properties are advantageous for the determination of lomefloxacin, offering advantages such as simple and rapid operation, low detection limits, and high accuracy.
[0020] 3. This invention uses readily available citric acid as a raw material to dope amino small molecules to prepare carbon quantum dots with high fluorescence performance, and successfully uses them for the sensing and determination of lomefloxacin with good results. The carbon dots are low in preparation cost, easy to operate, fast to detect and highly sensitive, and have good promotional value. Attached Figure Description
[0021] Figure 1 This is a high-resolution transmission electron microscope image of the fluorescent carbon dots obtained in Example 1;
[0022] Figure 2 The infrared spectrum of the fluorescent carbon dots obtained in Example 1;
[0023] Figure 3 The image shows the ultraviolet spectrum of the fluorescent carbon dots obtained in Example 1;
[0024] Figure 4 The fluorescence emission spectra of the carbon dot solutions obtained in Example 1 under excitation light of different wavelengths are shown.
[0025] Figure 5 This is a schematic diagram of the fluorescence signal of the fluorescent carbon dots obtained in Example 1 after continuous irradiation with excitation light at 395 nm for 10 h.
[0026] Figure 6 This is a schematic diagram of the fluorescence signal of the fluorescent carbon dots obtained in Example 1 after continuous irradiation with excitation light at 485 nm for 10 h.
[0027] Figure 7 The linear relationship between lomefloxacin in chicken meat. Detailed Implementation
[0028] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0029] Example 1
[0030] A fluorescent carbon dot, the preparation method of which includes the following steps:
[0031] 0.4 g of citric acid and 0.3 g of tyrosine were weighed and ultrasonically mixed with 20 mL of deionized water. The mixture was then hydrothermally reacted at 240 °C for 6 h. After filtration through a 0.22 μm microporous membrane, the filtrate was transferred to a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed for 24 h. The filtrate was then freeze-dried to obtain fluorescent carbon dots. The fluorescent carbon dot powder was dissolved in water, and its quantum yield was measured to be 3.63%.
[0032] High-resolution transmission electron microscopy (TEM) images, infrared spectra, ultraviolet spectra, fluorescence spectra, and fluorescence signal images after continuous irradiation with excitation light at 395 nm for 10 h were obtained for the obtained fluorescent carbon dots, as shown in the figures below. Figure 1-5 As shown. Among them, Figure 4 The highest points in the series, from top to bottom, are 385nm, 390nm, 395nm, and 400nm.
[0033] The results above show that the maximum excitation wavelength of the obtained fluorescent carbon dots is 395 nm and the maximum emission wavelength is 485 nm; moreover, the fluorescent carbon dots have a strong anti-photobleaching effect.
[0034] Example 2
[0035] A fluorescent carbon dot, the preparation method of which includes the following steps:
[0036] 0.4 g of citric acid and 0.2 g of tyrosine were weighed and ultrasonically mixed with 20 mL of deionized water. The mixture was then hydrothermally reacted at 240 °C for 5 h. After filtration through a 0.22 μm microporous membrane, the filtrate was transferred to a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed for 24 h. The filtrate was then freeze-dried to obtain fluorescent carbon dots. The fluorescent carbon dot powder was dissolved in water, and its quantum yield was measured to be 2.76%.
[0037] Example 3
[0038] A fluorescent carbon dot, the preparation method of which includes the following steps:
[0039] 0.1 g of citric acid and 0.3 g of tyrosine were weighed and ultrasonically mixed with 10 mL of deionized water. The mixture was then hydrothermally reacted at 220 °C for 6 h. After filtration through a 0.22 μm microporous membrane, the filtrate was transferred to a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed for 24 h. The filtrate was then freeze-dried to obtain fluorescent carbon dots. The fluorescent carbon dot powder was dissolved in water, and its quantum yield was determined to be 3.02%.
[0040] Example 4
[0041] A rapid detection method for lomefloxacin based on fluorescent carbon dots includes the following steps:
[0042] (1) Prepare a 0.05 mg / mL carbon dot solution by mixing the fluorescent carbon dots obtained in Example 1 with water. Take 50 μL of the solution and add 50 μL of lomefloxacin standard solution of different concentrations. Measure the fluorescence spectrum using 395 nm as the excitation wavelength. Figure 5 As shown, its fluorescence intensity was measured at the maximum emission wavelength of 485 nm, and the results are as follows. Figure 6 As shown, the linear equation for the change in fluorescence intensity with lomefloxacin concentration in the range of 0.781-400 μg / mL is ΔF = 79.651C - 693.61(R). 2=0.9931), the detection limit for lomefloxacin is 0.189 μg / mL;
[0043] (2) The fluorescence intensity change value of the sample to be tested is calculated according to y = F - F0, where F represents the fluorescence intensity of the carbon point when lomefloxacin is added and F0 represents the fluorescence intensity of the carbon point when lomefloxacin is not added; then the fluorescence intensity change value of the sample to be tested is substituted into the standard curve to calculate the concentration of lomefloxacin to be tested.
[0044] Example 5
[0045] The fluorescent carbon dots obtained in Example 1 were used for the detection of lomefloxacin residues in chicken meat, specifically including the following steps:
[0046] (1) Preparation of chicken extract: Take 200g of chicken, crush it into minced meat, and store it in a sealed container at -18℃; accurately weigh 2g of chicken minced meat into a 50mL centrifuge tube, add 10mL of extract (acetonitrile:water = 4:1), mix well, homogenize for 1min, centrifuge at 4000r / min for 15min, filter with a 0.22μm microporous membrane, and make up to 10mL to obtain blank chicken extract, which is stored at 0-4℃ for later use.
[0047] (2) Preparation of spiked chicken extract samples: Weigh 10 mg of lomefloxacin standard, dissolve it in 10 mL volumetric flask with chicken extract, sonicate to dissolve and then make up to volume to obtain 1 mg / mL spiked chicken extract sample, and then dilute it with chicken extract to prepare chicken spiked sample solutions of different concentrations.
[0048] The fluorescent carbon dots obtained in Example 1 were diluted with water to prepare a 0.05 mg / mL solution. 50 μL of this solution was then added to 50 μL of spiked chicken extract at different concentrations. The fluorescence intensity was measured at the maximum emission wavelength of 485 nm, with an excitation wavelength of 395 nm. The results are as follows: Figure 7 As shown, the linear equation for the change in fluorescence intensity with the concentration of lomefloxacin in chicken meat within the range of 0.0781-400 μg / mL is y = 79.651x + 693.61(R). 2 =0.9931). The fluorescence intensity change of the sample was calculated using y = F - F0, where F represents the fluorescence intensity of the carbon dots when lomefloxacin was added, and F0 represents the fluorescence intensity of the carbon dots when lomefloxacin was not added. Then, the fluorescence intensity change of the sample was substituted into the standard curve to calculate the concentration of lomefloxacin. The detection limit of lomefloxacin was 0.189 μg / mL, indicating that the prepared carbon dots have good sensitivity in determining lomefloxacin residues in chicken. The method recovery and precision results are shown in Table 1; as shown in Table 1, the prepared carbon dots have good accuracy and precision in determining lomefloxacin residues in chicken.
[0049] Table 1. Recovery and RSD of lomefloxacin in chicken meat
[0050]
[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A rapid detection method for lomefloxacin based on fluorescent carbon dots, characterized in that, Includes the following steps: (1) Prepare a carbon dot solution by mixing fluorescent carbon dots and water, and then add lomefloxacin standard solutions of different concentrations. The emission intensity at a wavelength of 485 nm is measured by a fluorescence spectrophotometer with 395 nm as the excitation wavelength. The standard curve equation is obtained by linear regression of the emission intensity change with the lomefloxacin concentration using the least squares method. The fluorescent carbon dots are prepared by the following method: using citric acid as carbon source and tyrosine as nitrogen source, they are ultrasonically mixed with deionized water and then hydrothermally reacted at 140-240℃ for 2-10 h. The mixture is then filtered, dialyzed and freeze-dried to obtain fluorescent carbon dots. The mass ratio of citric acid to tyrosine is 1:3-3:
1. The mass-volume ratio of citric acid to deionized water is 0.5 g: 10-25 mL. (2) The fluorescence intensity change value of the sample to be tested is calculated according to y = F - F0. Then, the fluorescence intensity change value of the sample to be tested is substituted into the standard curve to calculate the concentration of lomefloxacin to be tested. Wherein, F represents the fluorescence intensity of the carbon dot when lomefloxacin is added, and F0 represents the fluorescence intensity of the carbon dot when lomefloxacin is not added. (3) Preparation of sample extract: Take 200g of chicken meat, crush it into minced meat, and store it in a sealed container at -18℃; accurately weigh 2g of chicken minced meat into a 50mL centrifuge tube, add 10mL of acetonitrile:water extract, mix well, homogenize for 1min, centrifuge at 4000r / min for 15min, filter with a 0.22μm microporous membrane, and make up to 10mL to obtain blank chicken extract, which is stored at 0-4℃ for later use; Preparation of spiked chicken extract samples: Weigh 10mg of lomefloxacin standard, dissolve it in chicken extract in a 10mL volumetric flask, sonicate to dissolve, and make up to 1mL to obtain a 1mg / mL spiked chicken extract sample, and then dilute it with chicken extract to prepare chicken spiked sample solutions of different concentrations.
2. The rapid detection method for lomefloxacin based on fluorescent carbon dots as described in claim 1, characterized in that, In step (1), the filter is filtered through a 0.22μm microporous membrane. During dialysis, the molecular weight cutoff of the dialysis bag is 1000-5000Da, and the dialysis time is 12-48h.
3. The rapid detection method for lomefloxacin based on fluorescent carbon dots as described in claim 1, characterized in that, In step (1), the carbon dot solution concentration is 0.01-2.00 mg / mL.
4. The rapid detection method for lomefloxacin based on fluorescent carbon dots as described in claim 1, characterized in that, In step (2), the volume ratio of the carbon dot solution to the lomefloxacin standard solution is 1:0.5-5.
5. The rapid detection method for lomefloxacin based on fluorescent carbon dots as described in claim 1, characterized in that, In step (2), the volume ratio of the carbon dot solution to the lomefloxacin standard solution is 1:1.