A fluorescence analysis method for determining oxytetracycline in water samples
By synthesizing sulfur quantum dot fluorescent probes, the existing oleyroid detection methods are solved, and the high selectivity and high sensitivity detection of oleyroid in water samples is achieved, providing a simple and low-cost detection method.
Patent Information
- Application Number
- CN202210887584.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-07-26
- Publication Date
- 2025-08-08
- Estimated Expiration
- 2042-07-26
AI Technical Summary
The existing oleracin detection methods are expensive, have high technical requirements, and are cumbersome to sample pre-processing, and lack simple, low-cost and high-sensitivity detection methods.
The bottom-up method is used to synthesize sulfur quantum dots as fluorescence probes, and a simple, low-cost and high-sensitivity olefinic fluorescence measurement system is established by reacting with olefinicine.
It realizes high selective identification and high sensitivity detection of oleyroid in water samples, has the advantages of low cost and simple operation, and is suitable for the accurate determination of oleyroid in water samples.
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Figure CN115015209B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of fluorescence detection, and particularly relates to a fluorescence analysis method for determining oxytetracycline in a water sample. Background Art
[0002] Oxytetracycline, with its high antibacterial activity, low cost, and minimal side effects, is widely used in aquaculture. Its high detection rate in water samples poses potential risks to the environment and human health, necessitating accurate determination of residual oxytetracycline in water samples. Existing methods for detecting oxytetracycline include high-performance liquid chromatography, liquid chromatography-mass spectrometry, and capillary electrophoresis. These methods are expensive, require high technical requirements, and require tedious sample pretreatment. Therefore, the development of simple, low-cost, and highly sensitive methods for rapid detection of oxytetracycline is of great significance. Fluorescence analysis, with its high sensitivity and relatively inexpensive instrumentation, offers the potential for rapid determination of oxytetracycline. Sulfur quantum dots, which are free of heavy metals, exhibit low cytotoxicity, good biocompatibility, water dispersibility, and excellent photostability. Consequently, these methods have attracted considerable attention and research interest in ion and small molecule analysis, cell imaging, and other areas. Summary of the Invention
[0003] The present invention addresses the technical problem of providing a fluorescence analysis method for determining oxytetracycline in water samples. Using thioacetamide (TAA) as a sulfur source and PEG-400 as a protective agent, the present invention employs a bottom-up, one-step synthesis of sulfur quantum dots. These sulfur quantum dots exhibit the unique characteristic of highly selectively recognizing oxytetracycline. The sulfur quantum dot fluorescent probe assay system provided by the present invention exhibits strong selectivity and high sensitivity for identifying oxytetracycline in water samples.
[0004] The present invention adopts the following technical solution to solve the above technical problems, a fluorescence analysis method for determining oxytetracycline in water samples, characterized by the following specific steps:
[0005] Step S1: Synthesis of sulfur quantum dots: 4.80 mL of 0.10 mol / L thioacetamide, 8.50 mL of H2O, and 3.00 mL of PEG-400 were added to a reaction vessel in sequence at room temperature and stirred to mix evenly. 3.70 mL of 3 wt% hydrogen peroxide was then added dropwise and thoroughly mixed. The mixture was then stirred and reacted at 130°C for 4.5 h to obtain sulfur quantum dots, designated as SQDS@PEG-400.
[0006] Step S2: Drawing of the standard curve: 1.00 mL of the sulfur quantum dots obtained in step S1 was mixed with 0.50 mL of BR buffer solution with a pH of 7.0, and then oxytetracycline solution of different gradient concentrations was added to a constant volume of 4.00 mL. The mixture was stirred at 25 ° C for 30 min. ex=340nm, the fluorescence intensities F0 and F in the blank solution and in the presence of oxytetracycline were measured respectively, and △F=F0–F was calculated. In the range of oxytetracycline concentration from 0 to 40μM, there was a good linear relationship between △F and oxytetracycline concentration, and the linear equation was: △F=8.5122C+3.0375, R 2 =0.9904, detection limit 1.27 μM;
[0007] Step S3: Detection of oxytetracycline in water samples: 1.00 mL of the sulfur quantum dots obtained in step S1 was mixed with 0.50 mL of BR buffer solution with a pH of 7.0, and then the water sample to be tested was added and the volume was adjusted to 4.00 mL. The mixture was stirred at 25 ° C for 30 min and the mixture was stirred at λ ex =340nm, the fluorescence intensity is measured, and the oxytetracycline in the water sample to be tested is determined based on the measured fluorescence intensity and the linear equation obtained in step S2.
[0008] Compared with the prior art, the present invention has the following advantages and beneficial effects: Based on the highly selective fluorescence quenching effect of oxytetracycline, the present invention proposes a simple, low-cost, and highly sensitive oxytetracycline fluorescence determination system, and has been successfully applied to the determination of oxytetracycline in water samples. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 This is a feasibility analysis diagram of synthesizing sulfur quantum dots using different raw materials;
[0010] Figure 2 This is the excitation and emission spectra of sulfur quantum dots;
[0011] Figure 3 This is the effect curve of pH on the stability of sulfur quantum dots;
[0012] Figure 4 This is the curve of the effect of ionic strength on the stability of sulfur quantum dots;
[0013] Figure 5 is the standard curve drawn;
[0014] FIG6 is a curve showing the selectivity and anti-interference performance of the oxytetracycline determination system. DETAILED DESCRIPTION
[0015] The above contents of the present invention are further described in detail below through examples, but this should not be understood as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above contents of the present invention fall within the scope of the present invention.
[0016] Example
[0017] Step S1: Synthesis of sulfur quantum dots: 4.80 mL of 0.10 mol / L thioacetamide, 8.50 mL of H2O, and 3.00 mL of PEG-400 were added to a reaction vessel in sequence at room temperature and stirred to mix evenly. 3.70 mL of 3 wt% hydrogen peroxide was then added dropwise and thoroughly mixed. The mixture was then stirred and reacted at 130°C for 4.5 h to obtain sulfur quantum dots, designated as SQDS@PEG-400.
[0018] Step S2: Drawing of the standard curve: 1.00 mL of the sulfur quantum dots obtained in step S1 was mixed with 0.50 mL of BR buffer solution with a pH of 7.0, and then oxytetracycline solution of different gradient concentrations was added to a constant volume of 4.00 mL. The mixture was stirred at 25 ° C for 30 min. ex =340nm, the fluorescence intensities F0 and F in the blank solution and in the presence of oxytetracycline were measured respectively, and △F=F0–F was calculated. In the range of oxytetracycline concentration from 0 to 40μM, there was a good linear relationship between △F and oxytetracycline concentration, and the linear equation was: △F=8.5122C+3.0375, R 2 =0.9904, the detection limit was 1.27 μM, and the oxytetracycline concentrations of 10 μM and 30 μM were measured 13 times in parallel, with relative standard deviations of 0.19% and 0.87% respectively;
[0019] Step S3: Detection of oxytetracycline in water samples: 1.00 mL of the sulfur quantum dots obtained in step S1 was mixed with 0.50 mL of BR buffer solution with a pH of 7.0, and then the water sample to be tested was added and the volume was adjusted to 4.00 mL. The mixture was stirred at 25 ° C for 30 min and the mixture was stirred at λ ex =340nm, the fluorescence intensity is measured, and the oxytetracycline in the water sample to be tested is determined based on the measured fluorescence intensity and the linear equation obtained in step S2.
[0020] Figure 1This is a feasibility analysis diagram of synthesizing sulfur quantum dots with different raw materials. The optimal conditions for synthesizing sulfur quantum dots are: 4.80mL, 0.10mol / L thioacetamide, 8.50mL H2O and 3.00mL PEG-400 are added to the reaction vessel in sequence at room temperature and stirred thoroughly for 10 minutes. Then 3.70mL, 3wt% hydrogen peroxide is added dropwise and mixed thoroughly. Then, the sulfur quantum dots (SQDS@PEG-400) are prepared by stirring the reaction at 130°C for 4.5h. Under the optimal experimental conditions, if the reaction temperature, time and reaction system volume (20.00mL) are kept unchanged, in order to examine the indispensability of thioacetamide, hydrogen peroxide and PEG-400, the fluorescence properties of the reaction systems such as thioacetamide, PEG-400, thioacetamide + hydrogen peroxide, PEG-400 + hydrogen peroxide, thioacetamide + PEG-400, thioacetamide + PEG-400 + hydrogen peroxide were further investigated (such as Figure 1 ). Figure 1 It can be seen that sulfur quantum dots can only be successfully synthesized under the coexistence of thioacetamide, PEG-400 and hydrogen peroxide.
[0021] Figure 2 The excitation spectrum and emission spectrum of sulfur quantum dots are shown in Figure 2. Figure 2 It can be seen that the maximum excitation wavelength of sulfur quantum dots is 340 nm, and the maximum emission wavelength is 426.06 nm.
[0022] Figure 3 The curve of the effect of pH value on the stability of sulfur quantum dots. Figure 3 It can be seen that the fluorescence performance of sulfur quantum dots remains stable within a wide pH range (2.0-11.0).
[0023] Figure 4 This is the curve showing the effect of ionic strength on the stability of sulfur quantum dots. Figure 4 The effects of sodium chloride concentrations of 10mmol / L, 20mmol / L, 30mmol / L, 40mmol / L, 50mmol / L, 60mmol / L, 80mmol / L, 100mmol / L, 150mmol / L, 200mmol / L, 250mmol / L, 300mmol / L, and 500mmol / L on the fluorescence properties of sulfur quantum dots are given. Under conditions of higher ionic strength, the fluorescence properties of sulfur quantum dots are slightly reduced.
[0024] Figure 5 To draw the standard curve, 1.00 mL of sulfur quantum dots was mixed with 0.50 mL of BR buffer solution with pH = 7.0, and then oxytetracycline solution of different gradient concentrations was added to make the volume 4.00 mL, mixed well, and reacted at 25 ° C for 30 min. ex=340nm, the fluorescence intensities F0 and F in the blank solution and in the presence of oxytetracycline were measured respectively, and △F=F0–F was calculated. In the range of oxytetracycline concentration from 0 to 40μM, there was a good linear relationship between △F and oxytetracycline concentration, and the linear equation was: △F=8.5122C+3.0375, R 2 =0.9904.
[0025] Figure 6 shows the selectivity and anti-interference performance curve of the oxytetracycline determination system. 1.00 mL of sulfur quantum dots was mixed with 0.50 mL of a solution with a pH of 7.0, oxytetracycline and / or interfering substances were added, the volume was fixed to 4.00 mL, mixed, and reacted at 25 ° C for 30 min. ex =340nm, the fluorescence intensity of the system was measured. The concentration of oxytetracycline was 25μM and interfering substances such as the common cation Na in water samples + NH4 + , K + 、Ni 2+ , Ca 2+ 、Cd 2+ 、Al 3+ Cr 3+ 、Co 2+ 、Ba 2+ 、Zn 2+ 、Hg 2+ 、Mn 2+ 、Cu 2+ 、Fe 3+ 、Fe 2+ 、Cr(VI)、Pb 2+ 、Ag + and anions F-, Br - 、NO2 - 、HCO3 - 、CO3 2- 、NO3 - 、Cl - 、SO4 2- 、SO3 2- The concentration of each was 100 μM. Figure 6 (A), Figure 6 (B) and Figure 6 (C) show that the assay system provided by the present invention has the unique characteristics of highly selectively identifying oxytetracycline and strong anti-interference ability. The assay system is only sensitive to high concentrations of Fe 3+ 、Cr(VI)、Fe 2+ Plasma is slightly responsive.
[0026] Application of the determination method
[0027] Take tap water (water sample 1), groundwater (water sample 2), river water (water sample 3) and lake water (water sample 4), filter them and set aside. Mix 1.00mL of sulfur quantum dots (SQDS@PEG-400) with 0.50mL of BR buffer solution (pH=7.0), add a certain volume of water sample, make up to 4.00mL, mix well, and react at 25℃ for 30min. ex =340nm, and the fluorescence intensities F0 and F in the blank and in the presence of oxytetracycline were measured respectively. Oxytetracycline was not detected in any of the water samples. Further spike recovery tests were carried out, with 10μM and 30μM oxytetracycline added, respectively. The experimental results are shown in Table 1. The spike recovery rate was between 99.5% and 101.5%, and the relative standard deviation was within the range of 0.04% to 0.61%. This shows that the fluorescence determination method provided by the present invention was successfully applied to the analysis of oxytetracycline in water samples.
[0028] Table 1. Determination of actual water samples
[0029]
[0030] The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the scope of the principles of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.
Claims
1. A fluorescence analysis method for determining oxytetracycline in water samples, characterized in that The specific steps are: Step S1: Synthesis of sulfur quantum dots: 4.80 mL of 0.10 mol / L thioacetamide, 8.50 mL of H2O, and 3.00 mL of PEG-400 were added to a reaction vessel in sequence at room temperature and stirred to mix evenly. 3.70 mL of 3 wt% hydrogen peroxide was then added dropwise and thoroughly mixed. The mixture was then stirred and reacted at 130°C for 4.5 h to obtain sulfur quantum dots. Step S2: Drawing of the standard curve: 1.00 mL of the sulfur quantum dots obtained in step S1 was mixed with 0.50 mL of BR buffer solution with a pH of 7.0, and then oxytetracycline solution of different gradient concentrations was added to a constant volume of 4.00 mL. The mixture was stirred at 25 ° C for 30 min. ex =340nm, the fluorescence intensities F0 and F in the blank solution and in the presence of oxytetracycline were measured respectively, and △F=F0–F was calculated. In the range of oxytetracycline concentration from 0 to 40μM, there was a good linear relationship between △F and oxytetracycline concentration, and the linear equation was: △F=8.5122C+3.0375, R 2 =0.9904, detection limit 1.27 μM; Step S3: Detection of oxytetracycline in water samples: 1.00 mL of the sulfur quantum dots obtained in step S1 was mixed with 0.50 mL of BR buffer solution with a pH of 7.0, and then the water sample to be tested was added and the volume was adjusted to 4.00 mL. The mixture was stirred at 25 ° C for 30 min and the mixture was stirred at λ ex =340nm, the fluorescence intensity is measured, and the oxytetracycline in the water sample to be tested is determined based on the measured fluorescence intensity and the linear equation obtained in step S2.