Method for detecting concentration of levofloxacin in wastewater

Abstract

The invention discloses a method for detecting the concentration of levofloxacin in wastewater. Comprising the following steps: sequentially carrying out purification treatment, ion exchange solid-phase extraction and reversed-phase solid-phase extraction on the wastewater containing levofloxacin, and carrying out quantitative detection by adopting an HPLC-UV (High Performance Liquid Chromatography-Ultraviolet) and ultraviolet dual-wavelength detection method. Two solid-phase extraction columns are combined to serve as a sample pretreatment method, and most matrix interference in wastewater can be eliminated. HPLC-UV and ultraviolet dual-wavelength detection is adopted, so that the detection period is shortened, and quantitative detection of levofloxacin is realized. The method is simple, easy to operate and short in time consumption, and can provide technical support for detection of trace antibiotics in actual environmental water.

Description

Technical Field

[0001] The present application relates to a method for detecting the concentration of levofloxacin in wastewater, and belongs to the field of analysis of trace organic matter in water environment. Background Art

[0002] Levofloxacin (LZD) is a third-generation quinolone drug with strong antibacterial effect. It is mainly used in clinical practice for various infections caused by Gram-negative bacteria, but only a small part of it will be metabolized or absorbed by the human body, and about 30% to 90% will be released into the water environment in its metabolites or original form with excrement; on the other hand, due to the lack of a complete standard for the content of antibiotics in wastewater containing antibiotics, while COD, ammonia nitrogen, total phosphorus, etc. meet the standards, a small amount of antibiotics are still discharged into the water environment, which may pose a potential threat to the ecosystem and even human health. Since the concentration level of antibiotics such as levofloxacin in the water environment is generally ng / L, the sensitivity of the detection method is required to be high and the detection is difficult. However, through sample pretreatment methods, trace antibiotics in environmental water can be enriched for easy detection.

[0003] Solid phase extraction is a pretreatment method for purifying liquid samples with solid adsorbents that is currently widely used. Compared with liquid-liquid extraction, it has the advantages of simple operation, less solvent used, and avoidance of emulsification. Chinese Patent Publication No. CN108760956A discloses a sample pretreatment device and content determination method for fluoroquinolone veterinary antibiotics in aquaculture wastewater, Chinese Patent Publication No. CN114577931A discloses a solid phase extraction-ultra-high performance liquid chromatography-tandem mass spectrometry rapid determination method for antibiotics in sewage, and Chinese Patent Publication No. CN113945658A discloses a method for simultaneously determining the content of 7 antibiotics in water samples. The sample pretreatment adopts solid phase extraction, but the solid phase extraction column used is single, the wastewater contains complex components and the matrix interference is serious, which will have a great impact on the determination results. Only a small part of the interference can be eliminated by a single solid phase extraction column, so it is necessary to establish a method of combining multiple solid phase extraction columns to eliminate the influence, improve the accuracy of the determination results, and better apply it to actual wastewater detection. Summary of the invention

[0004] The present invention aims to provide a sample pretreatment method for treating environmental wastewater containing levofloxacin. The advantage is that the ion exchange solid phase extraction column is combined with the reversed phase solid phase extraction column to eliminate most matrix interference effects and enhance the accuracy of the experimental results. The pretreatment method is simple to operate, low in cost, and a high recovery rate of the test substance levofloxacin can be obtained.

[0005] According to one aspect of the present application, a method for detecting the concentration of levofloxacin in wastewater is provided, comprising the following steps:

[0006] The wastewater containing levofloxacin was purified, subjected to ion exchange solid phase extraction and reverse solid phase extraction in sequence, and quantitatively detected using HPLC-UV and ultraviolet dual wavelength detection.

[0007] The source of the wastewater containing levofloxacin is selected from at least one of medical wastewater, aquaculture wastewater, and pharmaceutical factory wastewater;

[0008] The pH of the wastewater containing levofloxacin is 6-9.

[0009] The purification treatment is selected from at least one of a filtration method and an electrocatalytic method.

[0010] The extraction column used in the ion exchange solid phase extraction is selected from at least one of MAX, MCX, 717 strong basic anion exchange resin, and PSA;

[0011] The solid-to-liquid ratio of the extraction column used in the ion exchange solid phase extraction to the wastewater containing levofloxacin is 1 to 12 mg / mL.

[0012] The extraction column used in the reverse phase solid phase extraction is selected from C 18 , HLB at least one;

[0013] The solid-to-liquid ratio of the extraction column used in the reverse solid-phase extraction to the wastewater containing levofloxacin is 1.25-10 mg / ml.

[0014] The pH of the treated wastewater containing levofloxacin is 1.5-6.

[0015] Na2SO3 is added to the purified wastewater, and the mass of the added Na2SO3 is 1.5 to 3 times that of the residual chlorine.

[0016] The activation, balancing, eluting and washing of the reverse phase solid phase extraction column are completed by adding a certain volume of solvent to the solid phase extraction column. The solvent is water, methanol / water in different proportions and different pH values, and the volume is 1-3 mL.

[0017] The HPLC-UV and ultraviolet dual wavelength detection method is used to detect levofloxacin and is obtained according to the established standard curve.

[0018] Specifically, the steps include:

[0019] Wastewater purification: Treat the sediment in the wastewater to obtain a relatively pure system;

[0020] Ion exchange solid phase extraction: Ion exchange solid phase extraction is used to absorb interfering substances in wastewater and collect the solution after reaction;

[0021] The mass of the ion exchange solid phase extraction column is 100-600 mg.

[0022] The volume of the wastewater loaded onto the ion exchange solid phase extraction column is 50 to 100 mL.

[0023] Reverse-phase solid-phase extraction: The wastewater after ion exchange solid-phase extraction is transferred to a reverse-phase solid-phase extraction column that has been activated and balanced, and the impurities are removed by elution, and finally the mixture containing levofloxacin is eluted;

[0024] The mass of the reversed-phase solid-phase extraction column is 50-100 mg.

[0025] The volume of the wastewater loaded onto the reverse phase solid phase extraction column after ion exchange solid phase extraction is 10 to 40 mL.

[0026] Detection: The eluate obtained from solid phase extraction was quantitatively detected using HPLC-UV and ultraviolet dual-wavelength detection method.

[0027] The beneficial effects of this application include:

[0028] 1. The method of the present invention uses two solid phase extraction columns in combination as a sample pretreatment method, which can eliminate most of the matrix interference in the wastewater.

[0029] 2. The method of the present invention adopts HPLC-UV and ultraviolet dual-wavelength detection, which shortens the detection cycle and realizes the quantitative detection of levofloxacin.

[0030] 3. The method of the present invention is simple, easy to operate, and short in time, and can provide technical support for the detection of trace antibiotics in actual environmental water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the liquid chromatogram after treatment with 717 strong basic anion exchange resin + HLB column in Example 1.

[0032] Figure 2 This is the liquid chromatogram after PSA+HLB column treatment in Example 3. DETAILED DESCRIPTION

[0033] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0034] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0035] The HPLC conditions were: injection volume 20 μL, 10% formic acid / water gradient elution, flow rate 1 mL / min, column C 18 (4.6×150mm, 5μm), ultraviolet absorption wavelength 295nm.

[0036] Example 1

[0037] A sample pretreatment method for treated environmental wastewater containing levofloxacin uses 717 strong alkaline anion exchange resin + HLB column to treat spiked medical wastewater. The actual medical wastewater is filtered with filter paper to remove sediments such as silt, and 5‰ NaCl is added to the filtered water sample. Electrocatalytic technology is used to sterilize, disinfect, and degrade some organic pollutants in the water sample. The water sample after electrocatalytic treatment contains NaClO, which has strong oxidizing properties and will oxidize the solid phase extraction column, affecting the adsorption effect. Therefore, Na2SO3 twice the mass of the residual chlorine contained in the water sample is added to neutralize it.

[0038] Weigh 300 mg of 717 strong alkaline anion exchange adsorbent and load it into a 3 mL column. Seal both ends with sieve plates. Take 50 mL of neutral water sample, add 1 mg / mL mixed standard solution (containing 7 substances: sulfathiazole, levofloxacin, tetracycline, linezolid, sulfadoxine, sulfamethoxazole, chloramphenicol), pass through the 717 column, and collect the water sample after passing through the column; take 30 mL and add 55 μL HCl to adjust the pH to 2, transfer to the HLB column (3 mL, 60 mg) activated and balanced with 3 mL of methanol and 3 mL of water, and use 3 mL of pH = 3 5% methanol / water for elution, and 3 mL of pH = 3 30% methanol / water for elution, and collect the eluate. HPLC-UV detection is used, and the results are shown in Figure 1 Linezolid, sulfadoxine, sulfamethoxazole, and chloramphenicol can all be adsorbed, and most of the sulfathiazole is adsorbed. Ultraviolet dual-wavelength detection is used to eliminate the influence of tetracycline, thereby achieving quantitative detection of levofloxacin.

[0039] Prepare 5, 10, 50, 100, 500, and 1000 ng / mL spiked water samples. According to the above experimental method, collect the eluates of each concentration. Perform linear regression with the peak area as the ordinate and the concentration as the abscissa. The results are shown in Table 1. The linear relationship is good. This standard curve can be used to determine the concentration of levofloxacin in water samples of unknown concentration.

[0040] Table 1 Linear parameters of levofloxacin and tetracycline

[0041] antibiotic Linear equations <![CDATA[R 2 ]]> Levofloxacin y=895.270x-22635.000 0.9978 tetracycline y=35.546x+1338.500 0.9949

[0042] Example 2

[0043] The eluate obtained after the unknown concentration of medical wastewater was treated with 717+HLB was simultaneously subjected to HPLC-UV detection and ultraviolet absorption measurement to obtain the corresponding peak area and absorbance values ​​at 295nm and 374nm. The peak area standard curve was used to obtain the levofloxacin concentration, and the ultraviolet dual-wavelength detection method was used to eliminate the interference of tetracycline to obtain the levofloxacin concentration. The results obtained were compared, and the results are shown in Table 2, which are basically consistent.

[0044] Table 2 Comparison of levofloxacin concentrations obtained by 717+HLB HPLC-UV and UV dual wavelength detection

[0045]

[0046] Example 3

[0047] As described in Example 1, the difference is that: the anion exchange solid phase extraction column uses PSA (3mL, 500mg), that is, PSA+HLB is used in combination for quantitative detection of levofloxacin. The eluate is collected and detected by HPLC-UV. Linezolid, sulfadoxine, sulfamethoxazole, and chloramphenicol can all be adsorbed, most of tetracycline is adsorbed, and ultraviolet dual-wavelength detection is used to eliminate the influence of sulfathiazole, thereby achieving quantitative detection of levofloxacin. Figure 2 This is the liquid chromatogram after PSA+HLB column treatment in Example 3.

[0048] Linear regression was performed and the results are shown in Table 3. This standard curve can be used to determine the concentration of levofloxacin in water samples of unknown concentration.

[0049] Table 3 Linear parameters of levofloxacin and sulfathiazole

[0050] antibiotic Linear equations <![CDATA[R 2 ]]> Levofloxacin y=816.603x-17713.013 0.9964 Sulfathiazole y=46.925x-1135.481 0.9932

[0051] Example 4

[0052] As described in Example 2, the difference is that: the eluent obtained after the water sample of unknown concentration is treated with PSA+HLB is simultaneously subjected to HPLC-UV detection and ultraviolet absorption measurement to obtain the corresponding peak area and absorbance values ​​at 284nm and 302nm, and the peak area standard curve is used to obtain the levofloxacin concentration and the ultraviolet dual wavelength detection method is used to eliminate the interference of sulfathiazole to obtain the levofloxacin concentration. The obtained results are compared, and the results are shown in Table 4, which are basically consistent.

[0053] Table 4 Comparison of levofloxacin concentrations obtained by PSA+HLB HPLC-UV and UV dual wavelength detection

[0054]

[0055] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for detecting the concentration of levofloxacin in wastewater, characterized in that: The following steps are involved: The wastewater containing levofloxacin was purified, subjected to ion exchange solid phase extraction and reverse solid phase extraction in sequence, and quantitatively detected using HPLC-UV and ultraviolet dual wavelength detection.

2. The method according to claim 1, characterized in that The source of the wastewater containing levofloxacin is selected from at least one of medical wastewater, aquaculture wastewater, and pharmaceutical factory wastewater; The pH of the wastewater containing levofloxacin is 6-9.

3. The method according to claim 1, characterized in that The purification treatment is selected from at least one of a filtration method and an electrocatalytic method.

4. The method according to claim 1, characterized in that: The extraction column used in the ion exchange solid phase extraction is selected from at least one of MAX, MCX, 717 strong basic anion exchange resin, and PSA; The solid-to-liquid ratio of the extraction column used in the ion exchange solid phase extraction to the wastewater containing levofloxacin is 1 to 12 mg / mL.

5. The method according to claim 1, characterized in that The extraction column used in the reverse phase solid phase extraction is selected from C 18 , HLB at least one; The solid-to-liquid ratio of the extraction column used in the reverse solid-phase extraction to the wastewater containing levofloxacin is 1.25-10 mg / ml.

6. The method according to claim 1, characterized in that The pH of the treated wastewater containing levofloxacin is 1.5-6.

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