Dual-filler nanofibers, methods, and extraction devices for PFAS detection and analysis

Abstract

The present invention provides a double-filler nanofiber, method and extraction device for PFAS detection and analysis, which can effectively detect a variety of PFAS (perfluorinated polyfluorinated compounds) in biological sample matrices, and has the advantages of being economical and simple, having a high recovery rate and a low detection limit. The present invention provides a double-filler extraction device for PFAS detection and analysis, in which UiO-66-F4 / PAN nanofibers and UiO-66-NH2 / PAN nanofibers are filled at intervals in the pipette tip to form a double-filler solid phase extraction structure. The preparation method comprises: step 1, preparing UiO-66-F4 / PAN nanofibers; step 2, preparing UiO-66-NH2 / PAN nanofibers: electrospinning is performed using a diaminoterephthalic acid-polyacrylonitrile mixed electrospinning solution, which is dried and shredded and then added to a mixed solution dissolved in diaminoterephthalic acid and zirconium nitrate, heated to reflux and stirred, and then the product is filtered, cleaned and dried.

Description

Technical Field

[0001] The present invention belongs to the field of quantitative detection of pollutants in biological samples, and specifically relates to dual-filler nanofibers, methods and extraction devices for PFAS detection and analysis. Background Art

[0002] Perfluorinated polyfluorinated compounds (PFAS) are a class of synthetic compounds containing carbon-fluorine bonds. Due to their inherent thermal and chemical stability, they are widely used in various fields such as fire extinguishers, automobiles, buildings, and non-stick cookware, and accumulate in different media such as air, soil, and drinking water. In addition, these compounds are environmentally persistent and bioaccumulative, and are generally difficult to remove through traditional treatment methods. They can enter the human body through the digestive system, respiratory system, and skin, and change hormone levels and human homeostasis systems at very low doses (Gaballah et al., Environmental Health Perspectives, 2020, 128, 47005). PFAS have been detected in various human body fluid and tissue samples, including blood, urine, milk, and hair, but the concentrations are often as low as trace amounts or even exceeding measured levels (Annelise et al., Environmental Research, 2023, 219, 115096; Lara et al., Environment International, 2022, 170, 107656). Therefore, to accurately qualitatively and quantitatively analyze PFAS in various biological samples, a stable and reliable pretreatment method is needed to improve the sensitivity of the analysis and determination and reduce the detection limit.

[0003] The most commonly used method for detecting PFAS in biological samples is based on C 18 The current state of the art is to develop a sample pretreatment method for solid-phase extraction and cleanup using HLB polymer fillers. However, these commercial solid-phase extraction cartridges are primarily targeted at anionic compounds. For emerging PFAS containing novel functional groups, zwitterionic and cationic species, the extraction efficiency does not meet the instrument detection requirements. In addition, when applied to biological samples, there is interference from matrix effects. Establishing a method with stable recovery, low detection limit, economy, simplicity, and applicability for the quantitative detection of multiple PFAS in biological samples remains a major challenge. Summary of the Invention

[0004] The present invention is made to solve the above-mentioned problems, and its purpose is to provide dual-filler nanofibers, methods and extraction devices for PFAS detection and analysis, which can effectively detect multiple PFAS in biological sample matrices and have the advantages of being economical, simple, high in recovery rate and low in detection limit.

[0005] In order to achieve the above object, the present invention adopts the following scheme:

[0006] <Device>

[0007] The present invention provides a dual-filler extraction device for PFAS detection and analysis, in which UiO-66-F4 / PAN nanofibers and UiO-66-NH2 / PAN nanofibers are alternately filled in the pipette tip to form a dual-filler solid-phase extraction structure.

[0008] Preferably, the dual-filler extraction device for PFAS detection and analysis provided by the present invention uses a sterile cotton spacer between the UiO-66-F4 / PAN nanofiber and the UiO-66-NH2 / PAN nanofiber.

[0009] Preferably, the dual-filler extraction device for PFAS detection and analysis provided by the present invention is filled with UiO-66-F4 / PAN nanofibers and UiO-66-NH2 / PAN nanofibers respectively in the two spacing spaces formed between the three layers of sterile cotton in the pipette tip.

[0010] Preferably, the dual-filler extraction device for PFAS detection and analysis provided by the present invention has a filling mass ratio of UiO-66-NH2 / PAN nanofiber and UiO-66-F4 / PAN nanofiber of 1:1 to 3, preferably 1:1, and a total mass of 10 to 30 mg, preferably 20 mg.

[0011] Preferably, the double-filler extraction device provided by the present invention for preparing PFAS detection and analysis is filled to form a double-filler solid-phase extraction structure, and then the pipette tip and the syringe are connected together to prepare the solid-phase extraction device.

[0012] <Preparation method>

[0013] Furthermore, the present invention also provides a method for preparing dual-filler nanofibers for PFAS detection and analysis, comprising the following steps:

[0014] Step 1, preparing UiO-66-F4 / PAN nanofibers;

[0015] Step 2, preparation of UiO-66-NH2 / PAN nanofibers:

[0016] A diaminoterephthalic acid-polyacrylonitrile mixed electrospinning solution was used for electrospinning. After drying, a diaminoterephthalic acid-polyacrylonitrile nanofiber membrane was obtained. The nanofiber membrane was then cut into pieces and added to a mixed solution of ultrapure water / acetic acid containing diaminoterephthalic acid and zirconium nitrate. The mixture was heated under reflux and stirred. The product was filtered, washed, and dried to obtain UiO-66-NH2 / PAN nanofibers.

[0017] Preferably, in the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention, in step 2, the mass concentration of the shredded diaminoterephthalic acid-polyacrylonitrile nanofiber membrane added to the mixed solution is 4 to 16% (w / w%).

[0018] Preferably, the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention comprises the following steps: in step 1, electrospinning is performed using a tetrafluoroterephthalic acid-polyacrylonitrile mixed electrospinning solution, and after drying, a tetrafluoroterephthalic acid-polyacrylonitrile nanofiber membrane is obtained, and then the nanofiber membrane is cut into pieces and added to a mixed solution of ultrapure water / acetic acid containing tetrafluoroterephthalic acid and zirconium nitrate, heated under reflux and stirred, and the product is filtered, washed, and dried to obtain UiO-66-F4 / PAN nanofibers.

[0019] Preferably, in the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention, in step 1 and step 2, after the nanofiber membrane is cut into pieces, the size of each piece is no larger than 1 cm*1 cm.

[0020] Preferably, in the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention, in steps 1 and 2, the electrospinning process parameters are set to: a solution injection flow rate of 0.5 to 1.0 mL / h driven by a syringe pump, a voltage of 15 to 20 kV between the spinning needle end and the receiver, a distance of 15 to 20 cm between the spinning needle end and the receiver, and a working environment temperature of 25 to 28°C.

[0021] Preferably, in the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention, step 1 specifically includes the following sub-steps:

[0022] Step 1-1, dissolving polyacrylonitrile in N,N-dimethylformamide, stirring and heating for several hours, adding a certain amount of tetrafluoroterephthalic acid, and continuing to heat and stir for a period of time to prepare a homogeneous tetrafluoroterephthalic acid-polyacrylonitrile electrospinning solution;

[0023] Step 1-2, transferring the mixed electrospinning solution obtained in step 1-1 into a syringe barrel, performing electrospinning to obtain a nanofiber membrane, and then drying the nanofiber membrane to obtain a tetrafluoroterephthalic acid-polyacrylonitrile nanofiber membrane material;

[0024] In step 1-3, a certain amount of tetrafluoroterephthalic acid and zirconium nitrate are weighed and dissolved in a mixed solution of ultrapure water / acetic acid, and then the tetrafluoroterephthalic acid-polyacrylonitrile nanofiber membrane prepared in step 1-2 is cut into pieces and added. After heating under reflux and stirring for a period of time, the white product is collected by filtration.

[0025] Step 1-4: soak the white product in step 1-3 in methanol and dichloromethane for several days, and then dry it to obtain UiO-66-F4 / PAN nanofibers.

[0026] Preferably, the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention comprises, in step 1-1, dissolving polyacrylonitrile (PAN) in N,N-dimethylformamide and heating and stirring at 80-100°C for 5-7 hours, adding tetrafluoroterephthalic acid and continuing to stir for 10-12 hours, and finally obtaining a mixed electrospinning solution having a tetrafluoroterephthalic acid concentration of 1-5% (w / v%), preferably 2%.

[0027] Preferably, in the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention, in steps 1-3, the mass ratio of tetrafluoroterephthalic acid and zirconium nitrate pentahydrate is 1:1 to 3, preferably 1:2, the volume ratio of water and acetic acid is 5 to 1:2, preferably 3:2, and the mass concentration of the added shredded tetrafluoroterephthalic acid-polyacrylonitrile nanofiber membrane material is 4 to 16% (w / w%), preferably 12%.

[0028] Preferably, in the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention, step 2 specifically includes the following sub-steps:

[0029] Step 2-1, dissolving polyacrylonitrile in N,N-dimethylformamide, stirring and heating for several hours, adding a certain amount of diaminoterephthalic acid, and continuing to heat and stir for a period of time to prepare a homogeneous diaminoterephthalic acid-polyacrylonitrile mixed electrospinning solution;

[0030] Step 2-2, transferring the mixed electrospinning solution into a syringe barrel, performing electrospinning to obtain a nanofiber membrane, and then drying the nanofiber membrane to obtain a diaminoterephthalic acid-polyacrylonitrile nanofiber membrane material;

[0031] In step 2-3, a certain amount of diaminoterephthalic acid and zirconium nitrate are weighed and dissolved in a mixed solution of ultrapure water / acetic acid. The diaminoterephthalic acid-polyacrylonitrile nanofiber membrane prepared in step 2-2 is then cut into pieces and added to the mixture. After heating under reflux and stirring for a period of time, the white product is collected by filtration.

[0032] Step 2-4: soak the white product in step 2-3 in methanol and dichloromethane for several days, and then dry it to obtain UiO-66-NH2 / PAN nanofibers.

[0033] Preferably, in the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention, in step 2-1, polyacrylonitrile is dissolved in N,N-dimethylformamide, and heated and stirred at 80-100°C for 5-7 hours, and diaminoterephthalic acid is added and stirred for 10-12 hours. The concentration of diaminoterephthalic acid in the final mixed electrospinning solution is 1-5% (w / v%), and the optimal concentration is 2%.

[0034] Preferably, in the method for preparing dual-filler nanofibers for PFAS detection and analysis provided by the present invention, in step 2-3, the mass ratio of diaminoterephthalic acid and zirconium nitrate pentahydrate is 1:1-3, preferably 1:2.5, the volume ratio of water and acetic acid is 1-5:2, preferably 4:1, and the mass concentration of the added shredded diaminoterephthalic acid-polyacrylonitrile nanofiber membrane material is 4-16% (w / w%), preferably 13%.

[0035] <Dual Filler Nanofiber>

[0036] Furthermore, the present invention also provides dual-filler nanofibers for PFAS detection and analysis, which are prepared using the method described in the above <Preparation Method>.

[0037] <Detection method>

[0038] Furthermore, the present invention also provides a PFAS detection and analysis method, which is characterized by comprising the following steps:

[0039] Step I. Activation: Activate the dual-packing extraction device described in any one of the <Device> with ultrapure water and methanol in sequence; in the dual-packing extraction device, form a dual-packing solid phase extraction structure in the pipette tip and connect it to the syringe;

[0040] Step II. Extraction: Add the liquid sample to be tested to a centrifuge tube, then add various PFAS standard solutions to prepare a working solution. Adjust the pH to 6-7 with dilute hydrochloric acid. Extract each sample several times (2-8 times) through a syringe.

[0041] Step III. After elution and volume adjustment, add the organic phase in the liquid chromatograph to re-dissolve, filter through a filter membrane, take a sample, and detect using a liquid chromatography-mass spectrometry instrument.

[0042] Preferably, in the method for quantitative detection of trace fluorinated compounds provided by the present invention, in step I, the added PFAS includes 4:2FTS (1H,1H,2H,2H-sodium perfluorohexanesulfonate), 6:2FTS (1H,1H,2H,2H-sodium perfluorooctanesulfonate), 6:2diPAP (6:2 polyfluoroalkyl phosphate diester), 6:6PFPi (bis perfluorohexylphosphinate sodium salt), 6:2Cl-PFESA (6:2 polyfluoroalkyl ether carboxylic acid and ether sulfonic acid), 8:2Cl-PFESA (8: 2 polyfluoroalkyl ether carboxylic acids and ether sulfonic acids), L-PFBS (sodium perfluorobutane sulfonate), L-PFHpS (sodium perfluoroheptane sulfonate), L-PFHxS (sodium perfluorohexane sulfonate), L-PFOS (sodium perfluorooctane sulfonate), L-PFPeS (sodium perfluoropentane sulfonate), PFDA (perfluorodecanoic acid), PFHpA (perfluoroheptanoic acid), PFHxA (perfluorohexanoic acid), PFNA (perfluorononanoic acid), PFOA (perfluorooctanoic acid), PFTeDA (perfluorotetradecanoic acid), and PFUdA (perfluoroundecanoic acid).

[0043] Functions and effects of the invention

[0044] 1. The dual-filler nanofiber and dual-filler extraction device of the present invention can effectively detect a variety of PFAS, including perfluorocarboxylic acids, perfluorosulfonic acids, perfluoroalkylphosphonic acids and chlorine-containing perfluoro compounds, especially emerging PFAS containing new functional groups, zwitterionic and cationic types. The 18 detectable PFAS are specifically: 4:2FTS, 6:2FTS, 6:2diPAP, 6:6PFPi, 6:2Cl-PFESA, 8:2Cl-PFESA, L-PFBS, L-PFHpS, L-PFHxS, L-PFOS, L-PFPeS, PFDA, PFHpA, PFHxA, PFNA, PFOA, PFTeDA, and PFUdA.

[0045] 2. The detection limit is extremely low (0.0006~0.0961μg L -1 ), the recovery rate was stable at above 80% (cord blood samples: 84.4%-118.5%; breast milk samples: 81.6%-123.9%).

[0046] 3. The present invention proposes for the first time the use of a dual-filler approach for detection, and, under the same dosage, the dual-filler nanofibers proposed in the present invention have better detection effects than using either filler (UiO-66-F4 / PAN or UiO-66-NH2 / PAN) independently (see the comparative examples for details).

[0047] 4. The dual-filler nanofibers (dual-filler metal-organic framework nanofibers) prepared by the present invention have the characteristics of large specific surface area, high porosity and hydrophilicity.

[0048] 5. The dual-filler nanofibers prepared in the present invention can be used for the detection of PFAS in complex biological matrix samples, such as umbilical cord blood and breast milk, with little interference from the matrix and coexisting substances.

[0049] 6. The PFAS detection and analysis method based on double-filler nanofibers of the present invention is simple to operate, easy to implement, and has good detection effect.

[0050] In summary, the present invention has the advantages of being economical, simple, high in recovery, and having low limits of detection and quantification, and is very suitable for the accurate detection of PFAS in complex biological matrix samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the structure of a double-filler extraction device according to an embodiment of the present invention;

[0052] Figure 2 : The figures are physical pictures of the dual-filler extraction devices involved in the embodiments and comparative examples of the present invention, wherein (a) to (g) are physical pictures of the dual-filler extraction devices (filler is UiO-66-F4 / PAN + UiO-66-NH2 / PAN) used in Examples 1 to 5 of the present invention, the single-filler extraction device (filler is UiO-66-F4 / PAN) used in Comparative Example 1, and the single-filler extraction device (filler is UiO-66-NH2 / PAN) used in Comparative Example 2; Note: The symbol "-" in the text names and the symbol " / " in the character names herein both indicate compounding, i.e., compounding the two components before and after the symbol, not selecting one or the other;

[0053] Figure 3 The figures are scanning electron microscope (SEM) images of the synthetic materials in the examples and comparative examples of the present invention; wherein, A: UiO-66-NH2 nanocrystals; B: UiO-66-F4 nanocrystals; C: UiO-66-NH2 / PAN nanofibers; D: UiO-66-F4 / PAN nanofibers;

[0054] Figure 4 IR spectra of UiO-66-F4 / PAN and UiO-66-NH2 / PAN synthesized in the examples and comparative examples of the present invention;

[0055] Figure 5 Thermogravimetric analysis results of UiO-66-F4 / PAN and UiO-66-NH2 / PAN synthesized in the examples and comparative examples of the present invention;

[0056] Figure 6 The water contact angle test results of UiO-66-F4 / PAN and UiO-66-NH2 / PAN synthesized in the examples of the present invention and the comparative examples;

[0057] Figure 7 N2 adsorption-desorption isotherms of UiO-66-F4 / PAN and UiO-66-NH2 / PAN synthesized in the examples of the present invention and the comparative examples;

[0058] Figure 8 The pore size distribution diagram of UiO-66-F4 / PAN and UiO-66-NH2 / PAN synthesized in the examples of the present invention and the comparative examples;

[0059] Figure 9 This is a comparison chart of the detection effects of using dual-filler nanofibers (UiO-66-F4 / PAN+UiO-66-NH2 / PAN), single-filler metal-organic framework composite fiber materials (UiO-66-F4 / PAN) and single-filler metal-organic framework composite fiber materials (UiO-66-NH2 / PAN) in the embodiments of the present invention and the comparative examples. DETAILED DESCRIPTION

[0060] The specific embodiments of the dual-filler nanofibers, methods, and extraction devices for PFAS detection and analysis according to the present invention are described in detail below with reference to the accompanying drawings.

[0061] <Example 1>

[0062] UiO-66-F4 / PAN: First, 1g of polyacrylonitrile was dissolved in 9.47mL of N,N-dimethylformamide at 600rpm and 90°C for 6 hours. Then, 0.1g of tetrafluoroterephthalic acid was added and heating and stirring continued for 12 hours. After the solution cooled, it was loaded into a 10mL syringe for electrospinning. During electrospinning, the temperature was controlled at 25-28°C, the voltage was 16kV, the flow rate was 0.8mL / h, and the distance from the tip to the collector was 15-20cm. The prepared fiber membrane was then baked in an oven at 60°C for 12 hours. 1.19g of tetrafluoroterephthalic acid and 2.2308g of zirconium nitrate were dissolved in 50mL of ultrapure water:acetic acid (3:2, v / v). 416mg of chopped fiber membrane (each fragment was no larger than 1cm x 1cm, which is not detailed here) was then added. The membrane was heated at 105°C and stirred at 600rpm for 24 hours. The white product was collected by filtration and immersed in methanol and dichloromethane at room temperature for three days each, during which the solvent in the beaker was discarded and replaced with fresh solvent. The resulting UiO-66-F4 / PAN product was dried in an 80°C oven for 6 hours.

[0063] UiO-66-NH2 / PAN: First, 1g of polyacrylonitrile was dissolved in 9.47mL of NN-dimethylformamide and heated at 90°C for 6 hours at 600rpm. Then, 0.1g of diaminoterephthalic acid (DAT) was added, and heating and stirring were continued for 12 hours. The solution was then transferred into a 10mL syringe for electrospinning. Electrospinning conditions were a temperature of 25-28°C, a voltage of 20kV, a flow rate of 1mL / h, and a distance of 15-20cm from the tip to the collector. The electrospun fiber membrane was baked in an oven at 60°C for 12 hours and then chopped for subsequent use. 905.73mg of DAT and 2.2308g of zirconium nitrate were dissolved in 50mL of ultrapure water:acetic acid (4:1, v / v). Then, 416mg of the chopped DAT was added. The mixture was heated at 105°C and stirred at 600rpm for 24 hours. The white product was collected by filtration and immersed in methanol and dichloromethane for three days each at room temperature. During this period, the solvent in the beaker was discarded and replaced with fresh solvent. Finally, the obtained UiO-66-NH2 / PAN product was dried in an oven at 80°C for 6 hours.

[0064] like Figure 1 As shown, 10 mg of UiO-66-NH2 / PAN and UiO-66-F4 / PAN nanofibers were weighed and placed in the middle of three layers of sterile cotton (in the two compartments formed by the three layers of sterile cotton), filled into a 1 mL pipette tip, and connected to a 10 mL syringe to obtain the following: Figure 2 (a) shows a dual-filler extraction device (solid phase extraction device based on dual-filler metal-organic framework composite fiber material).

[0065] like Figure 3 As shown, the UiO-66-F4 / PAN nanofibers and UiO-66-NH4 / PAN nanofibers prepared by the method of the present invention are composed of a micro-spherical structure (metal organic framework UiO-66-F4 or UiO-66-NH4 / PAN) and polyacrylonitrile nanofibers. The nanofiber network structure is the matrix, and the metal organic frameworks UiO-66-F4 and UiO-66-NH4 / PAN containing fluorine atom groups and amino groups are uniformly embedded and grown in the polymer matrix.

[0066] like Figures 4-5 As shown, the infrared spectrum and thermogravimetric characterization results are shown, which confirm that UiO-66-F4 / PAN nanofibers and UiO-66-NH4 / PAN nanofiber materials were prepared.

[0067] like Figures 6-7The results of water contact angle and N2 adsorption-desorption tests are shown in Figure 2, which confirm that the prepared dual-filler metal organic framework composite fiber material has the characteristics of large specific surface area, high porosity and hydrophilicity. Figure 7 It can be seen that UiO-66-NH2 / PAN shows a type I isotherm, and the adsorption amount increases rapidly at a slightly lower relative pressure stage, proving that the structure has a microporous structure, while UiO-66-F4 / PAN shows a typical type IV isotherm, which is a sign of mesopores.

[0068] like Figure 8 The pore size distribution diagram of UiO-66-F4 / PAN and UiO-66-NH2 / PAN nanofiber materials is shown in the figure. Figure 7 The isotherms of the nanofiber materials all showed hysteresis loops, indicating that the materials have mesopores or macropores. According to the results of the scanning electron microscopy, the existence of such macropores is due to the accumulation of particles and the formation of aggregation between particles. The BET specific surface areas of UiO-66-NH2 / PAN and UiO-66-F4 / PAN are 637m 2 ·g -1 、261m 2 ·g -1 , and the pore volumes are 0.313 cm 3 ·g -1 、0.507cm 3 ·g -1 , the micropore volumes are 0.232m 2 ·g -1 、0.055m 2 ·g -1 The microporosity is 74% and 10% respectively, which proves that the pore structures of the two nanofiber materials are microporous and mesoporous respectively. Figure 8 The pore size distribution curves in Figure 3 show that the main pore sizes of UiO-66-NH2 / PAN and UiO-66-F4 / PAN nanofibers are 3.4 nm and 8.4 nm, respectively.

[0069] <Example 2>

[0070] The mass concentration of tetrafluoroterephthalic acid-polyacrylonitrile nanofiber membrane and diaminoterephthalic acid-polyacrylonitrile nanofiber membrane was changed to 4% (w / w%), and double-filler nanofiber (double-filler metal-organic framework composite fiber material) was prepared and filled in a double-filler extraction device.

[0071] UiO-66-F4 / PAN: First, 1g of polyacrylonitrile was dissolved in 9.47mL of N,N-dimethylformamide at 600rpm and 90°C for 6 hours. Then, 0.1g of tetrafluoroterephthalic acid was added and heated and stirred for 12 hours. After the solution cooled, it was loaded into a 10mL syringe for electrospinning. During electrospinning, the temperature was controlled between 25 and 28°C, the voltage was 16kV, the flow rate was 0.8mL / h, and the distance between the tip and the collector was 15 to 20cm. The prepared fiber membrane was baked in an oven at 60°C for 12 hours. 1.19g of tetrafluoroterephthalic acid and 2.2308g of zirconium nitrate were dissolved in 50mL of ultrapure water:acetic acid (3:2, v / v). Then, 137mg of the chopped fiber membrane was added and the mixture was heated at 105°C and stirred at 600rpm for 24 hours. The white product was collected by filtration and immersed in methanol and dichloromethane for three days each at room temperature. During this period, the solvent in the beaker was discarded and replaced with fresh solvent. Finally, the obtained UiO-66-F4 / PAN product was dried in an oven at 80°C for 6 hours.

[0072] UiO-66-NH2 / PAN: First, 1g of polyacrylonitrile was dissolved in 9.47mL of NN-dimethylformamide and heated at 90°C for 6 hours at 600rpm. Then, 0.1g of diaminoterephthalic acid (DAT) was added, and heating and stirring were continued for 12 hours. The solution was then transferred into a 10mL syringe for electrospinning. Electrospinning conditions were a temperature of 25-28°C, a voltage of 20kV, a flow rate of 1mL / h, and a distance of 15-20cm from the tip to the collector. The electrospun fiber membrane was baked in an oven at 60°C for 12 hours and then chopped for subsequent use. 905.73mg of DAT and 2.2308g of zirconium nitrate were dissolved in 50mL of ultrapure water:acetic acid (4:1, v / v). Then, 125mg of the chopped DAT was added. The mixture was heated at 105°C and stirred at 600rpm for 24 hours. The white product was collected by filtration and immersed in methanol and dichloromethane for three days each at room temperature. During this period, the solvent in the beaker was discarded and replaced with fresh solvent. Finally, the obtained UiO-66-NH2 / PAN product was dried in an oven at 80°C for 6 hours.

[0073] Weigh 10 mg of UiO-66-NH2 / PAN and UiO-66-F4 / PAN nanofibers respectively and place them in the middle of three layers of sterile cotton (the order of the two fillers is not required). Fill them into a 1 mL pipette tip and connect it to a 10 mL syringe to obtain the following: Figure 2 (b) Double-packing extraction device shown.

[0074] <Example 3>

[0075] The mass concentration of tetrafluoroterephthalic acid-polyacrylonitrile nanofiber membrane and diaminoterephthalic acid-polyacrylonitrile nanofiber membrane was changed to 16% (w / w%), and the dual-filler nanofiber was prepared and filled in the dual-filler extraction device.

[0076] UiO-66-F4 / PAN: First, 1g of polyacrylonitrile was dissolved in 9.47mL of N,N-dimethylformamide at 600rpm and 90°C for 6 hours. Then, 0.1g of tetrafluoroterephthalic acid was added and heated and stirred for 12 hours. After the solution cooled, it was loaded into a 10mL syringe for electrospinning. During electrospinning, the temperature was controlled between 25 and 28°C, the voltage was 16kV, the flow rate was 0.8mL / h, and the distance between the tip and the collector was 15 to 20cm. The prepared fiber membrane was baked in an oven at 60°C for 12 hours. 1.19g of tetrafluoroterephthalic acid and 2.2308g of zirconium nitrate were dissolved in 50mL of ultrapure water:acetic acid (3:2, v / v). Then, 547mg of the chopped fiber membrane was added and heated at 105°C with stirring at 600rpm for 24 hours. The white product was collected by filtration and immersed in methanol and dichloromethane for three days each at room temperature. During this period, the solvent in the beaker was discarded and replaced with fresh solvent. Finally, the obtained UiO-66-F4 / PAN product was dried in an oven at 80°C for 6 hours.

[0077] UiO-66-NH2 / PAN: First, 1g of polyacrylonitrile was dissolved in 9.47mL of NN-dimethylformamide and heated at 90°C for 6 hours at 600rpm. Then, 0.1g of diaminoterephthalic acid (DAT) was added, and heating and stirring were continued for 12 hours. The solution was then transferred into a 10mL syringe for electrospinning. Electrospinning conditions were a temperature of 25-28°C, a voltage of 20kV, a flow rate of 1mL / h, and a distance of 15-20cm from the tip to the collector. The electrospun fiber membrane was baked in an oven at 60°C for 12 hours and then chopped for subsequent use. 905.73mg of DAT and 2.2308g of zirconium nitrate were dissolved in 50mL of ultrapure water:acetic acid (4:1, v / v). Then, 502mg of the chopped DAT was added. The mixture was heated at 105°C and stirred at 600rpm for 24 hours. The white product was collected by filtration and immersed in methanol and dichloromethane for three days each at room temperature. During this period, the solvent in the beaker was discarded and replaced with fresh solvent. Finally, the obtained UiO-66-NH2 / PAN product was dried in an oven at 80°C for 6 hours.

[0078] Weigh 10 mg of UiO-66-NH2 / PAN and UiO-66-F4 / PAN nanofibers respectively and place them between three layers of sterile cotton. Fill them into a 1 mL pipette tip and connect it to a 10 mL syringe to obtain the following: Figure 2 (c) Double-packing extraction device shown.

[0079] <Example 4>

[0080] The filling mass ratio of UiO-66-NH2 / PAN nanofibers and UiO-66-F4 / PAN nanofibers was changed to 1:2, and the double-filling extraction device was filled.

[0081] Weigh 10 mg of UiO-66-NH2 / PAN and 20 mg of UiO-66-F4 / PAN nanofibers respectively and place them between three layers of sterile cotton. Fill them into a 1 mL pipette tip and connect it to a 10 mL syringe to obtain the following: Figure 2 (d) Double-packing extraction device shown.

[0082] <Example 5>

[0083] The filling mass ratio of UiO-66-NH2 / PAN nanofibers and UiO-66-F4 / PAN nanofibers was changed to 2:1, and the double-filling extraction device was filled.

[0084] like Figure 1 As shown, 20 mg of UiO-66-NH2 / PAN and 10 mg of UiO-66-F4 / PAN nanofibers were weighed and placed in the middle of three layers of sterile cotton, which were filled into a 1 mL pipette tip and connected to a 10 mL syringe to obtain the following: Figure 2 (e) Double-packing extraction device shown.

[0085] <Example 6>

[0086] The prepared dual-filler nanofibers were used for the extraction and detection of PFAS in actual umbilical cord blood samples.

[0087] Umbilical cord blood samples were collected from a maternal and infant cohort in a tertiary hospital.

[0088] Cord blood sample processing method: Take 0.5mL of plasma and add it to a 1.5mL centrifuge tube. After adding a certain amount of isotope standard, incubate it for three hours, then add 1mL of acetonitrile, vortex for two minutes, and centrifuge it at 8000rpm at 4℃ for ten minutes. Finally, take the supernatant and transfer it to a 50mL centrifuge tube. Blow dry under a gentle nitrogen flow, and then dilute it to 10mL with ultrapure water.

[0089] The extraction experiment process is as follows.

[0090] Activation: Take a double-packed extraction device filled with 20 mg of UiO-66-NH2 / PAN and UiO-66-F4 / PAN nanofibers and activate it with 1 mL of ultrapure water and 1 mL of methanol in sequence (use a syringe to absorb 1 mL of solution to soak the material and then discharge it).

[0091] Extraction: 10 mL of umbilical cord blood sample was added to a 50 mL polypropylene centrifuge tube. A working solution of 18 PFAS was prepared (multiple concentration gradient experiments were conducted, with PFAS working solution concentrations of 0 μg / L, 0.02 μg / L, 0.2 μg / L, and 2 μg / L). The pH was adjusted to 6 with dilute hydrochloric acid. Three replicates were prepared for each concentration gradient. Each independent sample was extracted by pumping the syringe four times, with each pump-and-pull cycle lasting at least 3 minutes.

[0092] Elution: Using acetonitrile containing 1% ammonia (v / v) as the elution solvent, perform elution by pushing and pulling the syringe rod three times, using 0.5 mL of eluent. Repeat each elution cycle three times to obtain 1.5 mL of eluate. The eluate was nitrogen-purged to 100 μL at 40-60°C. The volume was then reconstituted to 200 μL with a methanol solution containing 5 mM ammonium acetate and 0.1% formic acid (the same organic phase as the mobile phase in the HPLC). After filtering through a 0.22 μm filter, 5 μL of the sample was injected and analyzed by HPLC-MS.

[0093] The detection and recovery results are shown in Table 1. Twelve PFAS were detected in the actual cord blood samples, namely 6:2diPAP (0.41 μg / L), 6:2FTS (0.24 μg / L), 6:2Cl-PFESA (0.07 μg / L), L-PFHxS (0.14 μg / L), L-PFOS (0.54 μg / L), PFDA (0.03 μg / L), PFHpA (0.02 μg / L), PFHxA (0.03 μg / L), PFNA (0.03 μg / L), PFOA (2.91 μg / L), PFTeDA (0.07 μg / L), and PFUdA (0.03 μg / L). In addition, working solutions with concentration gradients of 0.02, 0.2 and 2 μg / L were set up respectively. After extracting 18 PFAS in umbilical cord blood using the dual-filler metal-organic framework composite fiber material prepared by the method of the present invention, the samples were injected for detection, and the recovery rates were 84.4% to 118.5%, confirming that the material of the present invention is suitable for the extraction, enrichment and detection of multiple trace PFAS in actual umbilical cord blood samples.

[0094] Table 1. Detection results of 18 PFAS in cord blood samples

[0095]

[0096] a:RSD, stands for relative standard deviation.

[0097] b: ND (not detected), indicating that the target compound was not detected in the actual sample.

[0098] <Example 7>

[0099] The prepared dual-filler nanofibers were used for the extraction and detection of PFAS in actual breast milk samples.

[0100] Breast milk samples were collected from a mother-infant cohort in a tertiary hospital.

[0101] Breast milk sample processing method: 4 mL of breast milk was transferred to a 15 mL centrifuge tube, mixed isotope standards were added, and incubated for three hours. After it was fully absorbed, 8 mL of acetonitrile was added to the 15 mL centrifuge tube, and then ultrasonicated at room temperature for one hour, followed by centrifugation at 8000 rpm for 10 minutes at 4°C and extraction of the supernatant. This extraction process was repeated three times. All the extracted supernatants were combined, dried with nitrogen, and then diluted to 10 mL with ultrapure water.

[0102] The extraction experiment process is as follows.

[0103] Activation: Take a double-filled extraction device filled with 20 mg of double-filled nanofibers and activate it with 1 mL of ultrapure water and 1 mL of methanol in sequence (use a syringe to absorb 1 mL of solution to soak the material and then discharge it).

[0104] Extraction: 10 mL of breast milk sample was added to a 50 mL polypropylene centrifuge tube. A working solution of 18 PFAS was prepared (multiple concentration gradient experiments were conducted, with PFAS working solution concentrations of 0 μg / L, 0.02 μg / L, 0.2 μg / L, and 2 μg / L). The pH was adjusted to 6 with dilute hydrochloric acid. Three replicates were prepared for each concentration gradient. Each independent sample was extracted by pumping the syringe four times, with each pump-and-pull cycle lasting at least 3 minutes.

[0105] Elution: Using acetonitrile containing 1% ammonia (v / v) as the elution solvent, perform elution by pushing and pulling the syringe rod three times, using 0.5 mL of eluent. Repeat each elution cycle three times to obtain 1.5 mL of eluate. The eluate was nitrogen-purged to 100 μL at 40-60°C. The volume was then reconstituted to 200 μL with a methanol solution containing 5 mM ammonium acetate and 0.1% formic acid (the same organic phase as the mobile phase in the HPLC). After filtering through a 0.22 μm filter, 5 μL of the sample was injected and analyzed by HPLC-MS.

[0106] The detection and recovery results are shown in Table 2. Ten PFAS were detected in actual breast milk samples, namely 6:2diPAP (0.19 μg / L), 6:2FTS (0.04 μg / L), 6:2Cl-PFESA (0.02 μg / L), L-PFHxS (0.05 μg / L), L-PFOS (0.24 μg / L), PFDA (0.01 μg / L), PFHxA (0.01 μg / L), PFNA (0.03 μg / L), PFOA (0.60 μg / L), and PFUdA (0.01 μg / L). In addition, working solutions with concentration gradients of 0.02, 0.2 and 2 μg / L were set up respectively. After extracting 18 PFAS in breast milk using the dual-filler metal-organic framework composite fiber material prepared by the method of the present invention, the samples were injected for detection, and the recovery rate was 81.6%-123.9%, confirming that the material of the present invention is suitable for the extraction, enrichment and detection of multiple trace PFAS in actual breast milk samples.

[0107] Table 2. Detection results of 18 PFAS in breast milk samples

[0108]

[0109] a:RSD, stands for relative standard deviation.

[0110] b: ND (not detected), indicating that the target compound was not detected in the actual sample.

[0111] <Comparative Example 1>

[0112] Single filler UiO-66-F 4 / The preparation method of PAN nanofibers is the same as that in Example 1.

[0113] Weigh 20 mg of UiO-66-F4 / PAN nanofibers and place them between two layers of sterile cotton. Fill the pipette tip with 1 mL of water and connect it to a 10 mL syringe to obtain the following: Figure 2 (f) UiO-66-F4 / PAN single filler extraction device shown.

[0114] <Comparative Example 2>

[0115] The preparation method of single filler UiO-66-NH2 / PAN nanofibers is the same as that in Example 1.

[0116] Weigh 20 mg of UiO-66-NH2 / PAN nanofibers and place them between two layers of sterile cotton. Fill the pipette tip with 1 mL of water and connect it to a 10 mL syringe to obtain the following: Figure 2 (g) UiO-66-NH2 / PAN single filler extraction device shown.

[0117] Under the same conditions and dosage, the detection effects of the UiO-66-F4 / PAN single filler extraction device and the UiO-66-NH2 / PAN single filler extraction device obtained in the two comparative examples were compared with the double filler (UiO-66-F4 / PAN+UiO-66-NH2 / PAN) extraction device used in Example 1 of the present invention. The results are as follows: Figure 9 As shown, under the conditions of equal amounts of adsorbent and target analyte, the dual-filler nanofiber and dual-filler extraction device of the present invention have far better extraction effects on target PFAS than the two nanofibers and two single-filler extraction devices. It shows that the dual-filler nanofibers have more adsorption sites and functional groups, which can significantly improve the extraction effect on PFAS. And as shown in Tables 1 and 2, compared with the prior art, the dual-filler nanofibers prepared by the present invention and the dual-filler extraction device formed by filling can detect more PFAS substances, a total of 18 species, especially for 6:2Cl-PFESA, 8:2Cl-PFESA, 6:2diPAP, 6:6PFPi, and PFTeDA, which are usually difficult to effectively detect with existing methods. Good detection effects are also obtained. In addition, the detection limit of the dual-filler nanofibers prepared by the present invention and the dual-filler extraction device formed by filling are particularly low, 0.0006~0.0961μg L -1 , which significantly improves the sensitivity and can more accurately detect the content of PFAS substances in samples.

[0118] The above embodiments are merely illustrative of the technical solutions of the present invention. The dual-filler nanofibers, methods, and extraction devices for PFAS detection and analysis involved in the present invention are not limited solely to those described in the above embodiments, but are subject to the scope defined by the claims. Any modifications, supplements, or equivalent substitutions made by those skilled in the art based on these embodiments are within the scope of protection claimed in the claims.

Claims

1. Application of a dual-filler extraction device in PFAS detection and analysis, characterized by: The pipette tip was filled with UiO-66-F4 / PAN nanofibers and UiO-66-NH2 / PAN nanofibers at intervals to form a dual-filler solid-phase extraction structure. The pipette tip was then connected to a syringe to form a dual-filler extraction device. Among them, the filling mass ratio of UiO-66-F4 / PAN nanofibers and UiO-66-NH2 / PAN nanofibers is 1:(1~3); The dual-packing solid-phase extraction structure can detect perfluorinated and polyfluorinated compounds in biological samples, including: 4:2 FTS, 6:2FTS, 6:2 diPAP, 6:6 PFPi, 6:2 Cl-PFESA, 8:2 Cl-PFESA, L-PFBS, L-PFHpS, L-PFHxS, L-PFOS, L-PFPeS, PFDA, PFHpA, PFHxA, PFNA, PFOA, PFTeDA, and PFUdA; The detection limit of the dual-filler solid-phase extraction structure in the detection of PFAS in biological samples is 0.0006~0.0961 μg / L.

2. The use of the dual-filler extraction device according to claim 1 in PFAS detection and analysis, characterized in that: in, Sterile cotton spacers were used between the UiO-66-F4 / PAN nanofibers and the UiO-66-NH2 / PAN nanofibers.

3. The use of the dual-filler extraction device according to claim 1 in PFAS detection and analysis, characterized in that: in, In the pipette tip, two spaces formed between three layers of sterile cotton were filled with UiO-66-F4 / PAN nanofibers and UiO-66-NH2 / PAN nanofibers, respectively.

4. Use of the dual-filler extraction device according to any one of claims 1 to 3 in PFAS detection and analysis, characterized in that: in, The method for preparing dual-filler nanofibers comprises the following steps: Step 1, preparing UiO-66-F4 / PAN nanofibers; Step 2, preparation of UiO-66-NH2 / PAN nanofibers: A diaminoterephthalic acid-polyacrylonitrile mixed electrospinning solution was used for electrospinning. After drying, a diaminoterephthalic acid-polyacrylonitrile nanofiber membrane was obtained. The nanofiber membrane was then cut into pieces and added to a mixed solution of ultrapure water and acetic acid containing diaminoterephthalic acid and zirconium nitrate. The mixture was heated under reflux and stirred. The product was filtered, washed, and dried to obtain UiO-66-NH2 / PAN nanofibers.

5. Application of the dual-filler extraction device according to claim 4 in PFAS detection and analysis, characterized in that: in, In step 2, the mass concentration of the shredded diaminoterephthalic acid-polyacrylonitrile nanofiber membrane added to the mixed solution is 4-16%.

6. Use of the dual-filler extraction device according to claim 4 in PFAS detection and analysis, characterized in that: in, In step 1, a tetrafluoroterephthalic acid-polyacrylonitrile mixed electrospinning solution is used for electrospinning. After drying, a tetrafluoroterephthalic acid-polyacrylonitrile nanofiber membrane is obtained. The nanofiber membrane is then cut into pieces and added to a mixed solution of ultrapure water and acetic acid containing tetrafluoroterephthalic acid and zirconium nitrate. The mixture is heated under reflux and stirred. The product is filtered, washed, and dried to obtain UiO-66-F4 / PAN nanofibers.

7. Use of the dual-filler extraction device according to any one of claims 1 to 3 in PFAS detection and analysis, characterized in that: in, The PFAS detection and analysis method includes the following steps: Step I. Activation: The dual-packing extraction device is activated sequentially with ultrapure water and methanol. In the dual-packing extraction device, a dual-packing solid-phase extraction structure is formed within the pipette tip and then connected to the syringe. Step II. Extraction: Add the liquid sample to be tested to a centrifuge tube, then add various PFAS standard solutions to prepare a working solution. Adjust the pH to 6-7 with dilute hydrochloric acid. Extract each sample several times using a syringe. Step III. After elution and volume adjustment, add the organic phase in the liquid chromatograph to re-dissolve, filter through a filter membrane, take a sample, and detect it using a liquid chromatography-mass spectrometry instrument.

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