A method for detecting fluoranthene in water

Abstract

The present application belongs to the technical field of environmental pollutant detection, and particularly relates to a method for detecting fluoranthene in water. The method provided by the present application extracts and enriches the to-be-detected fluoranthene on an organic microporous membrane as a solid-phase extraction medium in the sample pretreatment process, and can directly detect the fluoranthene on the organic microporous membrane after solid-phase extraction of the water sample without elution. Since the to-be-detected fluoranthene is separated from the water and adsorbed on the surface of the membrane material, the concentration is greatly improved, and the light signal can directly irradiate the to-be-detected fluoranthene on the enriched organic microporous membrane for excitation without refraction and reflection of water, so that the sensitivity is higher than that of the traditional solid-phase extraction method, time and reagents are saved, the detection cost is reduced, and the detection efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of environmental pollutant detection, and particularly relates to a method for detecting fluoranthene in water. BACKGROUND

[0002] Polycyclic aromatic hydrocarbons (PAHs) are compounds with two or more benzene rings fused together, which are persistent organic pollutants. PAHs have relatively stable structures and very low water solubility, and are difficult to eliminate in the environment. Although the existence of PAHs in the environment is trace or trace, they are continuously generated in human production activities, easily migrate, transform, accumulate or degrade along the food chain and water cycle, and then enter the human body through the skin, digestive tract and respiratory tract, participate in the metabolic action of the body, have potential carcinogenicity, teratogenicity and mutagenicity, and the toxicity increases with the increase of benzene rings.

[0003] As a kind of polycyclic aromatic hydrocarbon, fluoranthene is oxidized and hydroxylated under the action of oxidase in cell particles, and the produced epoxide or phenolic compound generates glucoside, sulfate or glutathione conjugate. Some epoxides may be metabolized into dihydrodiols, which are sequentially combined to generate soluble detoxification products or oxidized into diol-epoxides, which are considered to be the final carcinogens causing cancer.

[0004] At present, there are many studies on the detection of fluoranthene and other PAHs in soil, atmosphere, rivers and food to evaluate the potential harm of fluoranthene and other PAHs to humans. Since PAHs are hydrophobic substances with low solubility in water and complex mechanisms, the detection of fluoranthene and other PAHs is very challenging. At present, the commonly used detection methods for fluoranthene in water are gas chromatography and high performance liquid chromatography, but gas chromatography and high performance liquid chromatography are not easy for on-site rapid detection, and liquid-liquid extraction and solid phase extraction need to be eluted after extraction, which affects the sensitivity of detection. SUMMARY

[0005] The purpose of the present application is to provide a method for detecting fluoranthene in water, which has high sensitivity without elution after solid phase extraction.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme:

[0007] The present application provides a method for detecting fluoranthene in water, comprising the following steps:

[0008] (1) using an organic microporous membrane to perform solid phase extraction on the water sample to be detected to obtain an enriched organic microporous membrane;

[0009] (2) using a light source with wavelength of 350-385 nm to excite the enrichment organic microporous membrane, collecting the fluorescence signal at 467 nm for analysis, and obtaining the content of fluoranthene in the water sample according to the intensity of the fluorescence signal and a predetermined standard curve; the standard curve is a relationship curve between the concentration of fluoranthene and the relative intensity of the fluorescence signal.

[0010] Preferably, the temperature of the solid phase extraction is 20-40℃.

[0011] Preferably, the distance between the light source and the enrichment organic microporous membrane is 1-8 cm during excitation; and the incident angle of the light source to the enrichment organic microporous membrane is 30-90 degrees.

[0012] Preferably, the organic microporous membrane is a nylon membrane, a polyether sulfone membrane or a polyamide membrane.

[0013] Preferably, the pore size of the organic microporous membrane is 0.1-0.5 μm.

[0014] Preferably, the pH value of the water sample to be measured is 4-10.

[0015] Preferably, the temperature of the excitation is 10-30℃.

[0016] Preferably, the light source is an LED light source, or a deuterium lamp and a grating are used simultaneously.

[0017] Preferably, the method for establishing the standard curve comprises the following steps:

[0018] (1) using an organic microporous membrane to perform solid phase extraction on a fluoranthene standard solution to obtain an enrichment organic microporous membrane; the concentration of the fluoranthene standard solution ranges from 1 to 100 μg / L;

[0019] (2) using a light source with wavelength of 350-385 nm to excite the enrichment organic microporous membrane, collecting the fluorescence signal at 467 nm for analysis, and establishing a standard curve with the concentration of fluoranthene as the horizontal coordinate and the relative intensity of the fluorescence signal as the vertical coordinate;

[0020] The method for preparing the fluoranthene standard solution comprises the following steps:

[0021] The fluoranthene standard and cyclohexane are premixed, and then the obtained premixed solution is mixed with a good solvent to obtain a fluoranthene standard solution.

[0022] Preferably, the device for solid phase extraction comprises a syringe and a filter arranged at the front end of the outlet of the syringe; the filter membrane in the filter is an organic microporous membrane.

[0023] The application provides a method for detecting fluoranthene in water. In the sample pretreatment process, the method uses an organic microporous membrane as a solid-phase extraction medium to extract and enrich the fluoranthene to be detected on the organic microporous membrane. After solid-phase extraction of the water sample, the fluoranthene can be directly detected on the organic microporous membrane without elution. Since the to-be-detected substance is separated from the water and adsorbed on the surface of the membrane material, the concentration is greatly improved. When detecting, the light signal can directly irradiate the to-be-detected substance on the enriched organic microporous membrane without refraction and reflection of water, so that the sensitivity is higher than that of the traditional solid-phase extraction method, time and reagents are saved, the detection cost is reduced, and the detection efficiency is improved.

[0024] The method provided by the application can detect fluoranthene in water, and has a good linear relationship in the range of 1-100 μg / L, a correlation coefficient R 2 of 0.997, a detection limit of 0.10 μg / L, a standard addition recovery of 90-110%, and a relative standard deviation (RSD) of 1-7%. The method provided by the application has the advantages of simple operation, strong anti-interference performance, fast response, portable instrument and low cost, and can be used for on-site rapid detection.

[0025] The method provided by the application has anti-interference performance: since the organic microporous membrane has a certain selectivity, part of the substances (such as low-molecular-weight alcohols, organic amines and amino acids) will not be adsorbed by the organic microporous membrane, so part of the substances in the water sample will directly flow through the organic microporous membrane during solid-phase extraction, which can be used for preliminary separation and purification, and signal interference caused by detection is avoided; in addition, the substances detected by fluorescence usually have specific excitation and emission wavelengths, and the substances with other excitation and emission wavelengths inconsistent with fluoranthene are not easy to interfere with the detection of the to-be-detected substance of the application. The method provided by the application does not need to additionally treat sodium, potassium, ammonium, copper, aluminum, acetate, sulfate, halogen, benzene, benzene series and naphthalene ions, and has high anti-interference performance on the above ions.

[0026] The method provided by the application can realize rapid analysis, and the detection period is shortened to 1-3 minutes / sample (the detection period of the existing liquid chromatography detection is usually 20-30 minutes / sample), and due to the volume advantage, the reagent kit can be carried to the scene for rapid detection, and has good market promotion potential.

[0027] Further, the organic microporous membrane is defined as a nylon membrane, a polyether sulfone membrane or a polyamide membrane, the specific surface area of the nylon membrane is large, the nylon membrane has certain polarity, and the nylon membrane can efficiently adsorb polycyclic aromatic hydrocarbon substances (such as naphthalene, anthracene, phenanthrene and pyrene and various substances). In the solid phase extraction process, the polycyclic aromatic hydrocarbon substances are easily migrated from water to the surface of the nylon membrane material, and the adsorption capacity of the polycyclic aromatic hydrocarbon substances on the nylon membrane is increased with the solid phase extraction, so that the rapid and efficient enrichment of trace polycyclic aromatic hydrocarbon substances can be realized. Then, when the fluorescence detection is used, the polycyclic aromatic hydrocarbon substances are accumulated on the surface of the organic microporous membrane, and the excitation of the fluorescence signal is easily realized. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0029] Figure 1 The flowchart of the solid phase extraction of the present application is shown in the figure.

[0030] Figure 2 The standard curve of the concentration of fluoranthene and the relative intensity of the fluorescence signal obtained by the embodiment of the present application is shown in the figure. The abscissa is the concentration of fluoranthene, and the ordinate is the relative intensity of the fluorescence signal. DETAILED DESCRIPTION

[0031] The present application provides a method for detecting fluoranthene in water, comprising the following steps:

[0032] (1) using an organic microporous membrane to perform solid phase extraction on the water sample to be detected to obtain an enriched organic microporous membrane;

[0033] (2) using a light source with a wavelength of 350-385nm to excite the enriched organic microporous membrane, collecting the fluorescence signal at 467nm for analysis, and obtaining the content of fluoranthene in the water sample to be detected according to the intensity of the obtained fluorescence signal and a predetermined standard curve; the standard curve is a relationship curve of the concentration of fluoranthene and the relative intensity of the fluorescence signal.

[0034] The present application uses an organic microporous membrane to perform solid phase extraction on the water sample to be detected to obtain an enriched organic microporous membrane. In the present application, the organic microporous membrane is preferably a nylon membrane, a polyether sulfone membrane or a polyamide membrane; the material of the nylon membrane is preferably one or both of nylon and nylon 66; the pore size of the organic microporous membrane is preferably 0.1-0.5μm, more preferably 0.22-0.45μm, and further preferably 0.3μm; the diameter of the organic microporous membrane is preferably 10-20mm, and more preferably 13-17mm.

[0035] In the present application, the water sample to be measured is preferably filtered before solid phase extraction to remove insoluble substances and suspended particles in the water sample to be measured; the filter membrane is preferably an organic filter membrane or qualitative filter paper; the organic filter membrane is preferably a glass fiber filter membrane, a polytetrafluoroethylene membrane, a polyvinylidene fluoride membrane, a cellulose acetate membrane, a cellulose membrane or a hemicellulose membrane; the pore size of the organic filter membrane is preferably 0.10-0.50 μm, more preferably 0.10-0.30 μm; the pore size of the qualitative filter paper is preferably 0.22-0.50 μm, more preferably 0.30-0.40 μm.

[0036] In the present application, the pH value of the water sample to be measured is preferably adjusted before solid phase extraction; the pH value of the water sample to be measured is preferably consistent with the pH value of the fluoranthene standard solution used to establish the standard curve; the reagent used to adjust the pH value of the water sample to be measured is preferably one or more of potassium dihydrogen phosphate, dipotassium hydrogen phosphate, sodium bicarbonate, sodium carbonate, potassium hydroxide and glacial acetic acid; the volume of the water sample to be measured is preferably consistent with the volume of the fluoranthene standard solution used to establish the standard curve.

[0037] In the present application, the temperature of solid phase extraction is preferably 20-40℃, more preferably 25-35℃; the device for solid phase extraction preferably comprises a syringe and a filter arranged at the front end of the outlet of the syringe; the filter membrane in the filter is preferably an organic microporous membrane; the syringe is preferably a needle cylinder syringe; the organic microporous membrane is sealed by the syringe and the filter in the present application, ensuring that the water sample to be measured or the fluoranthene standard solution does not leak during use. The syringe is used instead of a solid phase extraction column in the present application, making solid phase extraction more convenient and faster.

[0038] In the present application, the solid phase extraction preferably comprises the following steps: using a syringe to suck the water sample to be measured, then installing a filter with an organic microporous membrane at the front end of the syringe, and finally pushing the water sample to be measured out, as shown in Figure 1 The pushing speed of the water sample to be measured is preferably 1-10 mm / s, more preferably 3-6 mm / s.

[0039] After obtaining the enriched organic microporous membrane, the present application excites the enriched organic microporous membrane by using a light source with a wavelength of 350-385 nm, collects the fluorescence signal at 467 nm for analysis, and obtains the content of fluoranthene in the water sample to be tested according to the intensity of the obtained fluorescence signal and a predetermined standard curve. In the present application, the enriched organic microporous membrane is preferably removed from the filter after obtaining the enriched organic microporous membrane; the distance between the light source and the enriched organic microporous membrane during excitation is preferably 1-8 cm, more preferably 3-6 cm, and further preferably 5 cm; the incident angle of the light source to the enriched organic microporous membrane is preferably 30-90 degrees, and more preferably 50-70 degrees; the light source is preferably an LED light source, or a deuterium lamp and a grating are used simultaneously; the wavelength of the light source is preferably 360-370 nm, and more preferably 365 nm; the temperature of excitation is preferably 10-30°C, and more preferably 15-25°C; after collecting the fluorescence signal at 467 nm, the obtained fluorescence signal is preferably subjected to ultraviolet-visible diffuse reflection and / or fluorescence spectrum detection.

[0040] In the present application, the method for establishing the standard curve preferably comprises the following steps:

[0041] (1) solid-phase extraction of a fluoranthene standard solution by using an organic microporous membrane to obtain an enriched organic microporous membrane; the concentration of the fluoranthene standard solution is in the range of 1-100 μg / L;

[0042] (2) excitation of the enriched organic microporous membrane by using a light source with a wavelength of 350-385 nm, collection of the fluorescence signal at 467 nm for analysis, and establishment of a standard curve with the fluoranthene concentration as the horizontal coordinate and the fluorescence signal relative intensity as the vertical coordinate.

[0043] In the present application, the preparation method of the fluoranthene standard solution preferably comprises the following steps: premixing a fluoranthene standard and cyclohexane, then mixing the obtained premixed solution with a good solvent to obtain a fluoranthene standard solution; the good solvent preferably comprises one or more of methanol, ethanol, acetonitrile and acetone; the volume ratio of the cyclohexane and the good solvent is preferably 5-15: 85-95, more preferably 8-12: 88-92; the addition of cyclohexane in the preparation of the fluoranthene standard solution in the present application can play a role in solubilization and stabilization of the solution, so that the fluoranthene is fully dissolved in water. In the examples of the present application, the series of concentrations of the fluoranthene standard solution are subjected to solid phase extraction respectively, and then the obtained enriched organic microporous membranes are subjected to fluorescence signal detection respectively; the concentration range of the series of concentrations of the fluoranthene standard solution is 1-100 μg / L, more preferably 1, 2.5, 5, 10, 15, 25 and 50 μg / L; the volume of the fluoranthene standard solution is preferably 10-80 mL, more preferably 30-60 mL; the pH value of the fluoranthene standard solution is preferably adjusted before the solid phase extraction; the pH value of the fluoranthene standard solution is preferably 4-10, more preferably 6-8, further preferably 7; the reagent used for adjusting the pH value of the fluoranthene standard solution is preferably one or more of potassium dihydrogen phosphate, dipotassium hydrogen phosphate, sodium bicarbonate, sodium carbonate, potassium hydroxide and glacial acetic acid. The establishment steps of the standard curve in the implementation process of the present application can be omitted according to the actual situation, and there is no necessity of repeating.

[0044] In order to further illustrate the present application, the schemes of the present application are described in detail below in combination with the drawings and examples, but they should not be understood as limiting the scope of protection of the present application.

[0045] Example 1

[0046] (1) Preparation of a fluoranthene standard solution: a fluoranthene standard was weighed and dissolved in cyclohexane, and then diluted with methanol to 100 mL; the volume ratio of the cyclohexane and the methanol was 1:9;

[0047] (2) A series of concentrations of 2.5, 5, 10, 15, 25 or 50 μg / L of the fluoranthene standard solution was used, the pH value was 7, the volume was 5 mL, a syringe was used to suck the fluoranthene standard solution, then a filter with a nylon membrane with a pore size of 0.22 μm was installed at the front end of the syringe (the inner diameter was 13 mm) to perform solid phase extraction, and an enriched organic microporous membrane was obtained;

[0048] (3) The enriched organic microporous membrane was directly excited by using an LED light source with a wavelength of 365 nm, and the fluorescence signal at 467 nm was collected for fluorescence spectrum detection analysis, so as to establish a standard curve with the fluoranthene concentration as the abscissa and the fluorescence signal relative intensity as the ordinate, as shown in Figure 2 The equation of the standard curve is:

[0049] Y = 180 * C + 2500, R 2 = 0.998, the detection limit is 0.1 μg / L;

[0050] (4) The above steps (2) and (3) are repeated to quantitatively analyze the fluoranthene in river water, natural water and drinking water, and the results show that fluoranthene is not detected in the three water samples (no fluoranthene or the content of fluoranthene is lower than the detection limit);

[0051] (5) A series of fluoranthene standard samples are added to the above three water samples as the water samples to be detected, and the results are shown in Table 1.

[0052] Table 1: Detection results of three water samples to be detected

[0053]

[0054]

[0055] As shown in Table 1, the sample recovery rate of the detection method of fluoranthene in water provided by the present application is between 90-110%, the error is between 1-7%, the recovery rate is basically stable within the detection range, and the relative error is also at a relatively low level. It can be seen that the detection method of fluoranthene in water provided by the present application can accurately detect low-concentration fluoranthene in water samples, has high sensitivity and low detection limit.

[0056] As shown in the above examples, the detection method of fluoranthene in water provided by the present application can accurately detect low-concentration fluoranthene in water samples, has high sensitivity, and the detection limit can reach 0.1 μg / L.

[0057] Although the above examples have made a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained under the premise of no creativity according to the present embodiments, and these embodiments all belong to the protection scope of the present application.

Claims

1. A method for detecting fluoranthene in water, characterized by, The method comprises the following steps: (1) using an organic microporous membrane to perform solid phase extraction on a water sample to be measured, without elution, to obtain an enriched organic microporous membrane; (2) using a light source with a wavelength of 350-385 nm to excite the enriched organic microporous membrane, collecting a fluorescence signal at 467 nm for analysis, and obtaining the content of fluoranthene in the water sample to be measured according to the intensity of the fluorescence signal and a predetermined standard curve; the standard curve is a relationship curve between the concentration of fluoranthene and the relative intensity of the fluorescence signal.

2. The detection method according to claim 1, characterized in that, The temperature of the solid phase extraction is 20-40 DEG C.

3. The method of claim 1, wherein, When the excitation is performed, the distance between the light source and the enriched organic microporous membrane is 1-8 cm; and the incident angle of the light source to the enriched organic microporous membrane is 30-90 degrees.

4. The detection method according to claim 1 or 3, characterized in that, The organic microporous membrane is a nylon membrane, a polyether sulfone membrane or a polyamide membrane.

5. The detection method according to claim 1 or 3, characterized in that, The pore size of the organic microporous membrane is 0.1-0.5 microns.

6. The method of claim 1, wherein, The pH value of the water sample to be measured is 4-10.

7. The method of claim 1, wherein, The temperature of the excitation is 10-30 DEG C.

8. The detection method according to claim 1 or 3, characterized by, The light source is an LED light source, or a deuterium lamp and a grating are used simultaneously.

9. The method of claim 1, wherein, The method for establishing the standard curve comprises the following steps: (1) using an organic microporous membrane to perform solid phase extraction on a fluoranthene standard solution to obtain an enriched organic microporous membrane; the concentration of the fluoranthene standard solution ranges from 1 to 100 micrograms per liter; (2) using a light source with a wavelength of 350-385 nm to excite the enriched organic microporous membrane, collecting a fluorescence signal at 467 nm for analysis, and establishing a standard curve with the concentration of fluoranthene as the horizontal coordinate and the relative intensity of the fluorescence signal as the vertical coordinate; The method for preparing the fluoranthene standard solution comprises the following steps: Mixing a fluoranthene standard and cyclohexane, and then mixing the obtained premix with a good solvent to obtain a fluoranthene standard solution.

10. The method of claim 1, wherein, The device for solid phase extraction comprises a syringe and a filter arranged at the front end of the outlet of the syringe; the filter membrane in the filter is an organic microporous membrane.

Images