Sample pretreatment method for textile PFAS detection

Abstract

The invention discloses a sample pretreatment method for textile PFAS detection. The sample pretreatment method comprises the following steps: (1) preparing a treatment system; (2) combined contact; (3) magnetic separation; and (4) collecting supernatant. Fe3O4 is prepared through a coprecipitation method, and a bifunctional interface of amino and fluorine affinity groups is introduced through silanization, so that the selective interaction and matrix interference resistance of PFAS in a textile matrix are enhanced; the enrichment efficiency and the phase separation convenience can be enhanced on the premise of not obviously increasing the consumption of an organic solvent by combining with IL. By screening appropriate IL anion / cation pairs, phase transfer / extraction of PFAS is promoted, and dependence of traditional extraction on organic solvents is reduced due to the fact that IL can be recycled. By utilizing the rapidity of magnetic separation and the selective dissolution / extraction characteristic of IL, a sample pretreatment process which is less in unit operation, rapid in phase separation and recyclable is formed, the flux is improved, and the operation and waste liquid treatment cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sample pretreatment for textile detection, and particularly relates to a sample pretreatment method for textile PFAS detection. BACKGROUND

[0002] Per-and Polyfluoroalkyl Substances (PFAS) have strong C-F bonds and typical hydrophobic / lipophilic amphiphilic characteristics, and have been used for long-term waterproof and oil-proof finishing of textiles. Its chemical inertness and environmental persistence lead to accumulation risk in the environment and organisms. In recent years, international and domestic regulations on PFAS continue to tighten, and higher requirements are put forward for the limit value and information disclosure of PFAS in textiles.

[0003] Existing textile PFAS detection usually relies on processes such as organic solvent extraction + offline solid phase extraction (SPE), which has the following pain points:

[0004] (1) Matrix interference is heavy: dyes, auxiliaries and finishing residues cause significant matrix effect, and the recovery rate and quantitative accuracy fluctuate;

[0005] (2) Complicated process and high time consumption: multi-step extraction / purification and concentration lead to limited throughput and strong dependence on people;

[0006] (3) Large amount of solvent: a large amount of organic solvents such as methanol / acetonitrile bring cost and environmental burden, and the disposal pressure of waste liquid is great;

[0007] (4) Insufficient selectivity / difficult phase separation: single adsorbent or single extraction medium has limited selectivity for chain length / functionality of PFAS, and the phase separation and recovery link is inefficient.

[0008] Therefore, there is an urgent need for a sample pretreatment technology that can realize PFAS enrichment and matrix purification under mild conditions, and facilitate rapid phase separation and recovery. SUMMARY

[0009] The purpose of the present application is to provide a sample pretreatment method for textile PFAS detection, so as to solve the problems in the prior art and realize a sample pretreatment technology that can realize PFAS enrichment and matrix purification under mild conditions, and facilitate rapid phase separation and recovery.

[0010] The present application provides a sample pretreatment method for textile PFAS detection, comprising the following steps:

[0011] (1) Prepare the treatment system: add an ionic liquid (IL) to the treatment liquid and adjust the pH to 4-11, and control the temperature to be 10-55℃;

[0012] (2) combined contact: adding a magnetic Fe3O4 material bifunctionalized with 3-aminopropyl triethoxysilane (APTES) and fluorine-containing silane to the treatment system, so that the mass ratio of the magnetic Fe3O4 material to the ionic liquid is 1:4-1:20, and contacting a PFAS-containing textile sample with the treatment system for 30-90 min;

[0013] (3) magnetic separation: after the treatment is completed, an external magnetic field is applied to separate and recover the magnetic Fe3O4 material from the treatment liquid;

[0014] (4) supernatant collection: collecting the supernatant after separation as a to-be-tested liquid, or further purifying the supernatant for subsequent detection.

[0015] The sample pretreatment method for textile PFAS detection as described above, wherein preferably, the pH in step (1) is adjusted to 6-8, and the temperature is controlled at 30-45°C.

[0016] The sample pretreatment method for textile PFAS detection as described above, wherein preferably, the magnetic Fe3O4 material is obtained by coprecipitation of FeCl3·6H2O and FeCl2·4H2O in a mass ratio of Fe 3+ : Fe 2+ ≈2:1, and then silanization.

[0017] The sample pretreatment method for textile PFAS detection as described above, wherein preferably, the silane bifunctionalization is carried out in an anhydrous ethanol / water=95 / 5 (v / v) system at 60-80°C, the obtained material is Fe3O4@SiO2-APTES-F, and the addition amount of APTES is 5%-15% of the mass of the magnetic Fe3O4 material, and the addition amount of fluorine-containing silane is 2%-10%.

[0018] The sample pretreatment method for textile PFAS detection as described above, wherein preferably, the ionic liquid is selected from ionic liquids of 1-alkyl-3-methyl imidazole salts with BF4 － , TfO － , or NTf2 － anions.

[0019] The sample pretreatment method for textile PFAS detection as described above, wherein preferably, the mass ratio of the magnetic Fe3O4 material to the ionic liquid is 1:6-1:12.

[0020] The sample pretreatment method for textile PFAS detection as described above, wherein preferably, when the pH is 9-11, the ionic liquid is an ionic liquid of 1-alkyl-3-methyl imidazole salts with TfO －or NTf2 － Anionic 1-alkyl-3-methylimidazolium salt.

[0021] Compared with the prior art, the application prepares Fe3O4 by a coprecipitation method, and introduces a bifunctional interface of an amine group and a fluorine affinity group through silanization, thereby enhancing selective interaction with PFAS in a textile matrix and anti-matrix interference capability; in combination with IL, the enrichment efficiency and phase separation convenience can be enhanced without significantly increasing the consumption of organic solvents. By screening a suitable IL anion / cation pair, phase transfer / extraction of PFAS is promoted, and the dependence of traditional extraction on organic solvents is reduced due to the recyclability of IL. By using the rapidity of magnetic separation and the selective dissolution / extraction characteristics of IL, a sample pretreatment process with fewer unit operations, fast phase separation, and recyclability is formed, thereby improving the throughput and reducing the operation and waste liquid disposal costs. DETAILED DESCRIPTION

[0023] The application provides a sample pretreatment method for textile PFAS detection, comprising the following steps:

[0024] (1) Preparing a treatment system: adding an ionic liquid (IL) to a treatment solution and adjusting the pH to 4-11, and controlling the temperature to be 10-55℃;

[0025] (2) Combined contact: adding a magnetic Fe3O4 material bifunctionalized by 3-aminopropyltriethoxysilane (APTES) and a fluorine-containing silane to the treatment system, so that the mass ratio of the magnetic Fe3O4 material to the ionic liquid is 1:4-1:20, and a textile sample containing PFAS is contacted with the treatment system for 30-90 min;

[0026] (3) Magnetic separation: after the treatment is completed, an external magnetic field is applied to separate and recover the magnetic Fe3O4 material from the treatment solution;

[0027] (4) Supernatant collection: collecting the supernatant after separation as a test solution, or further purifying the supernatant and then using it for subsequent detection.

[0028] In the embodiments provided in the application, the pH in step (1) is adjusted to 6-8, and the temperature is controlled to be 30-45℃. The magnetic Fe3O4 material is prepared from FeCl3·6H2O and FeCl2·4H2O according to Fe 3+ : Fe 2+Fe3O4 prepared by co-precipitation with ≈2:1 ratio and silanization. The silane bifunctionalization was carried out in anhydrous ethanol / water = 95 / 5 (v / v) system at 60-80℃, and the obtained material was Fe3O4@SiO2-APTES-F, and the dosage of APTES was 5%-15% of the mass of magnetic Fe3O4 material, and the dosage of fluorine-containing silane was 2%-10%. The ionic liquid was selected from 1-alkyl-3-methylimidazole salt matched with BF4 － , TfO － or NTf2 － anion ionic liquid. The mass ratio of magnetic Fe3O4 material to ionic liquid was 1:6-1:12. When the pH was 9-11, the ionic liquid was 1-alkyl-3-methylimidazole salt matched with TfO － or NTf2 － anion.

[0029] Surface modification of magnetic Fe3O4 material: The present application prepares Fe3O4 by co-precipitation, and introduces bifunctional interface of amine group and fluorine affinity group through silanization, thereby enhancing selective interaction with PFAS in textile matrix and anti-matrix interference ability; and the combination with IL can strengthen enrichment efficiency and phase separation convenience without significantly increasing consumption of organic solvent.

[0030] Synergistic application of ionic liquid: By screening suitable IL anion / cation pairs, the phase transfer / extraction of PFAS is promoted, and the dependence on organic solvent in traditional extraction is reduced due to the recyclability of IL.

[0031] Optimization of pretreatment process: By using the rapidity of magnetic separation and the selective dissolution / extraction characteristics of IL, a sample pretreatment process with less unit operation, fast phase separation and recyclable is formed, thereby improving throughput and reducing operation and waste liquid disposal cost.

[0032] Compared with the control method (single use of magnetic Fe3O4 material, single use of IL, or traditional methanol extraction+SPE), the present application has:

[0033] (1) synergistic effect: under the same temperature / time / dosage conditions, the removal rate / enrichment degree and kinetic rate of the combination system to PFAS are significantly higher than those of the control, and the synergistic index η>1;

[0034] (2) matrix purification: in textile samples such as cotton, polyester and nylon, the LC-MS / MS matrix effect is obviously reduced, and the recovery rate is stable (RSD≤10%) after internal standard correction;

[0035] (3) green and recyclable: the performance is maintained (for example, the removal rate is ≥85%) after the material is recycled for ≥10 times, and the loss of IL is controllable;

[0036] (4) Industrialization: The external magnetic field realizes rapid phase separation, and the process is simple, which is convenient for online and large-scale implementation.

[0037] The preferred embodiments of the present application are described below, and it should be understood that the embodiments are used to better explain the present application, and are not used to limit the present application.

[0038] Test method: Residual PFAS is quantified by LC-MS / MS (triple quadrupole, reversed phase gradient elution, MRM mode); the matrix effect is calculated according to M.E. % = (A 基质加标 / A 纯溶剂加标 -1) × 100%; the ion liquid loss L (mg·L －1 ) is calculated by ion chromatography or 19 F-NMR to equivalent IL concentration by anion external standard.

[0039] Example 1: Preparation of Fe3O4 magnetic nanoparticles and bifunctionalization (APTES + fluorine-containing silane).

[0040] Ion liquid combination configuration

[0041] (A) Fe3O4 coprecipitation preparation

[0042] FeCl3·6H2O 5.406 g (0.020 mol) and FeCl2·4H2O 1.988 g (0.010 mol) were dissolved in deionized water (e.g. 100 mL), stirred at 80°C, and ammonia water was added to adjust pH ≈ 10, and reacted for 1 h. Separated by external magnetic field, washed with deionized water / ethanol alternately to near neutral, and vacuum dried at 60°C for 12 h to obtain Fe3O4 powder.

[0043] (B) Surface bifunctionalization (silanization)

[0044] 0.500 g (dry basis) of Fe3O4 was dispersed in anhydrous ethanol / water = 95 / 5 (v / v), total 50 mL, 0.050 g of APTES (10% relative to magnetic material) and 0.025 g of fluorine-containing silane (5% relative to magnetic material) were added, 0.2% (v / v) of glacial acetic acid was added dropwise as catalyst, and reacted at 70°C for 2 h. Magnetic separation, ethanol washing, and vacuum drying at 50°C to obtain Fe3O4@SiO2-APTES-F (denoted as "magnetic functional material").

[0045] (C) Ion liquid combination configuration

[0046] Preparation of the combined system: 0.500 g of magnetic Fe3O4 material was weighed and mixed with 5.000 g of 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4) (or an IL of the same type with the same mass) in 50.0 mL of deionized water. The mixture was stirred at 40°C and pH 7 for 60 min to obtain the combined system. When the performance was evaluated (see Example 2 / 3), the combined system was diluted to 100.0 mL with deionized water as needed, and then used. The sample dosage, initial PFAS concentration, and other evaluation conditions are indicated in the corresponding examples.

[0047] After the treatment, the magnetic Fe3O4 material was recovered from the treatment solution by an external magnetic field. The supernatant was used for subsequent LC-MS / MS analysis or further purification. The removal / enrichment performance of the combined system is shown in the subsequent examples and comparative examples (and the synergy index η is calculated).

[0048] Example 2: Evaluation of the combined treatment process and synergistic effect (standard solution system)

[0049] Objective: To evaluate the enrichment / removal performance of the combined functional Fe3O4 + ionic liquid (IL) system for PFAS under uniform conditions, and to calculate the synergy index η by comparing with the use of magnetic material alone and IL alone.

[0050] Reagents and conditions: PFAS standard solution (initial concentration 100 mg·L －1 ), functional Fe3O4 (Fe3O4@SiO2-APTES-F), [EMIM]BF4 (or an IL of the same type); 40°C, pH 7, 60 min; magnetic stirring.

[0051] Steps: (1) Preparation of the treatment system (combined): 0.100 g of functional Fe3O4 was weighed and mixed with 1.000 g of [EMIM]BF4 (magnetic material: IL = 1:10, mass ratio) in 100.0 mL of PFAS standard solution (or the IL was dissolved in a small amount of water and then diluted to 100.0 mL), and stirred at 40°C and pH 7 for 60 min. (2) Control system: only magnetic material: 0.100 g of magnetic material + 100.0 mL of PFAS (without IL), and the other conditions were the same; only IL: 1.000 g of IL + 100.0 mL of PFAS (without magnetic material), and the other conditions were the same. (3) Separation and detection: After the treatment, the magnetic Fe3O4 material was recovered from the treatment solution by an external magnetic field; the supernatant was filtered (0.22 μm) and the residual PFAS concentration was determined by LC-MS / MS. (4) Calculation: removal rate R = (C0-C) / C0×100%; synergy index η = R 联用 / max{R 仅磁材 , R 仅IL}, η > 1 indicates positive synergy exists in combination.

[0052] Under the above experimental conditions, the removal rate of PFAS in the combination system can reach 98.4% ± 2.7 (see Table 1); compared with the magnetic material only and IL only controls, η is calculated according to the synergy index formula (see Table 1).

[0053] Table 1 Removal rate and synergy index of combination and control

[0054]

[0055] Note: R (%) is expressed as "mean ± RSD (n = 3)"; the unit of RSD is percentage point.

[0056] Example 3: Endpoint and preferred window verification of combination ratio (1:4, 1:6, 1:10, 1:12, 1:20)

[0057] To verify the endpoint and preferred window of the combination ratio, under the same conditions as Example 2 (PFAS 100 mg·L －1 ; 40℃; pH 7; 60 min), five ratios of 1:4, 1:6, 1:10, 1:12, and 1:20 were investigated; for each ratio, an independent magnetic material only control (0.100 g) and IL only control (IL mass consistent with the corresponding combination ratio) were set. After treatment, the magnetic material was recovered from the treated solution by separating it with an external magnetic field, and the supernatant was filtered through a 0.22 μm filter. The residual PFAS was measured by LC-MS / MS, and the removal rate R and synergy index η were calculated. The results showed (see Table 2) that 1:6-1:12 was the preferred window (consistent with 1:10 baseline); the endpoint 1:4 had a low IL amount with R = 89.2%, and the endpoint 1:20 had a high IL amount but was affected by viscosity / competition, with R = 96.1% also lower than 1:10; the synergy index η of the five groups was all > 1, and the synergy of 1:20 decreased to 1.28, indicating that "the more IL, the better" was not true. The "magnetic material only" controls of different ratios were from independent batches, and the difference was not significant (p > 0.05) by single factor analysis of variance.

[0058] Table 2 Effect of different combination ratios on removal rate and synergy index (mean ± RSD, n = 3; 100 mg·L －1 ; 40℃; pH 7; 60 min)

[0059]

[0060] Example 4: Process window optimization (temperature) + matrix effect + recycling and IL loss

[0061] 1. Effect of temperature on the combination system (standard solution 100 mg·L －1)

[0062] Example 2: 1:10 ratio and the same volume / time / pH, respectively, at 10, 25, 40, 55°C (the rest unchanged), the results are shown in Table 3: 98.4% removal rate at 40°C; 89.5% and 85.3% at 10°C and 55°C, respectively.

[0063] Table 3 Effect of different temperatures on removal rate (mean ± RSD, n = 3; 1:10, 100 mg·L －1 )

[0064]

[0065] Note: R (%) is expressed as "mean ± RSD (n = 3)"; the unit of RSD is percentage points.

[0066] 2, Matrix effect and recovery rate (spiked on textile substrate)

[0067] To evaluate the improvement of the combined pretreatment on the matrix effect of LC-MS / MS and the stability of the spiked recovery rate. Cotton / polyester / nylon substrates were selected, and the matrix extract was obtained by blank pretreatment; the target concentrations (50, 100 μg·L －1 ) were spiked with PFAS (100 mg·L －1 level to represent the process window; the recovery rate and matrix effect were detected at 50 / 100 μg·L －1 level to match the linear range of LC-MS / MS). The spiked samples on the matrix and the pure solvent were both treated according to the combined process of Example 2. The spiked recovery rate calculation formula is: spiked recovery rate % = 100 × detected concentration after spiking / spiking concentration; the matrix effect (M.E. %) calculation formula is: M.E. % = (A 基质加标 / A 纯溶剂加标 -1) × 100%, and the experimental results are shown in Table 4.

[0068] Table 4 Recovery rate and matrix effect of matrix spiking (mean ± RSD, n = 3; internal standard method)

[0069]

[0070] Note: Recovery (%) and M.E. % are both expressed as "mean ± RSD (n = 3)"; the unit of RSD is percentage points.

[0071] 3, Circulation stability and IL loss (100 mg·L －1 , 1:10)

[0072] 100 mg·L －1, magnetic material: IL = 1:10, 40℃, pH 7, 60min, the same batch of magnetic functionalized material and ionic liquid were continuously cycled for 10 times: after each treatment, the magnetic Fe3O4 material was recovered from the treatment solution by an external magnetic field, and the IL was recovered for the next cycle (water was added as necessary to constant volume); the removal rate R was recorded for each cycle i (i = 1…10) and IL loss L i (mg·L －1 , by ion chromatography 19 F-NMR〔BF4 － 〕 external standard quantitative); the retention rate % = 100 x R 10 / R1 represents the performance retention (target ≥ 85%), and the cumulative IL loss = ΣL is given i and the mean ± RSD (n = 3) of single loss as the evaluation index of cycle stability and greenness, the experimental results are shown in Table 5, the experimental results show that: under the same experimental conditions (magnetic material: IL = 1:10; 100mg·L －1 ; 40℃; pH 7; 60min), the retention rate of the method after 10 cycles is = 88.1% (≥ 85%), the cumulative IL loss ΣL i = 102.7mg·L －1 , converted V = 0.100L to 10.27mg (≈1.03%); each point result is the mean ± RSD (n = 3) and RSD ≤ 5%. Therefore, the method has good reusability and low IL loss, meeting the technical requirements of "retention rate ≥ 85% after 10 times, IL relative loss ≤ 1.5%".

[0073] Table 5 Cycle stability and IL loss (1:10; 100mg·L －1 ; 40℃; pH 7; 60min; mean ± RSD, n = 3)

[0074]

[0075]

[0076] Note: R i (%), L i (mg·L －1 ), retention rate % and cumulative IL loss are expressed as "mean ± RSD (n = 3)"; the unit of RSD is percentage point.

[0077] Example 5: Effect of pH on removal of PFAS by the combined system

[0078] To evaluate the effect of different pH conditions on the removal of PFAS by functionalized Fe3O4 combined with ionic liquid (IL) and to determine the optimal pH window, a PFAS standard solution of 100 mg·L⁻¹ was used. －1 0.100 g of functionalized Fe3O4 (Fe3O4@SiO2-APTES-F) and 1.000 g of [EMIM]BF4 (magnetic material: IL = 1:10) were added to a 100.0 mL system and magnetically stirred at 40 °C for 60 min. The pH was adjusted using a 10 mM buffer system (pH 4: acetate / sodium acetate; pH 6 / 7 / 8: phosphate; pH 11: carbonate) while maintaining approximately consistent ionic strength. After treatment, the magnetic material was separated and recovered from the treated solution using an applied magnetic field. The supernatant was filtered through a 0.22 μm filter and the residual PFAS was determined by LC-MS / MS (results are shown in Table 6). The experimental results show that pH 6–8 (preferably 7) is the optimal window; the pH decreases significantly under strong acid / strong base conditions, which is presumably related to changes in the ionization state of PFAS and interfacial interactions.

[0079] Table 6. Effect of different pH values ​​on removal rate (mean ± RSD, n = 3; 1:10, 100 mg·L⁻¹) －1 )

[0080]

[0081] Example 6: Anion Substitution of Ionic Liquids and Adaptation to Alkaline Conditions

[0082] Under the same conditions as in Example 2 (magnetic material: IL = 1:10; PFAS 100 mg·L), －1 At 40℃ for 60 min, three ionic liquids, [EMIM]BF4, [BMIM]NTf2, and [HMIM]TfO, were used respectively. The pH was adjusted by a 10 mM buffer system (pH 7: phosphate; pH 9 / 11: carbonate / borate, with similar ionic strength). Each pH / IL combination included controls with only magnetic material (0.100 g) and only IL (1.000 g). After treatment, the magnetic material was separated and recovered from the treated solution using an applied magnetic field. The supernatant was filtered through a 0.22 μm filter, and residual PFAS was measured by LC-MS / MS, followed by ion chromatography / 19 F-NMR external standard quantification of single IL loss (mg·L) L (mg·L) －1 The removal rate R and synergistic index η were calculated, and the experimental data are shown in Table 7. The data showed that at pH 7, the combined use of the three ILs resulted in R ≈ 98%, with no significant difference. Under pH 9 / 11 conditions, [BMIM]NTf2 / [HMIM]TfO maintained a high removal rate (≥93–95%) and low L (≈10–12 mg·L⁻¹). －1 [EMIM]BF4 showed a decline in performance (pH 11: 86.5%) and an increase in L (18.9 mg·L⁻¹).－1 ).

[0083] Table 7 Removal rate, synergistic index and IL loss of anion exchange at different pH values ​​(mean ± RSD, n = 3; 1:10; 100 mg·L⁻¹) －1 (40℃; 60min)

[0084]

[0085] Example 7: Dynamics comparison of magnetization followed by IL, IL followed by magnetization, and synchronous operation.

[0086] Under the same experimental conditions (PFAS 100 mg·L⁻¹) －1 ;Fe3O4@SiO2-APTES-F 0.100g;

[0087] [EMIM]BF4 1.000g, magnetic material:IL = 1:10; system 100.0mL; 40℃, pH 7 [10mM phosphate buffer]; 60min), three processes were compared: simultaneous addition of magnetic material and IL at t=0, magnetic material first then IL (magnetic material only for the first 30min, IL added at 30min), and IL first then magnetic material (IL only for the first 30min, magnetic material added at 30min); samples were taken at t=10, 20, 30, 40, 50, and 60min, and the supernatant was filtered to 0.22μm before residual PFAS was measured by LC-MS / MS according to R(t) = (C0-C t The removal rate is calculated as (1 - C0) × 100%, and the conversion score X = R / 100 is used to fit a pseudo-first-order model (PFO): -ln(1-X) = k app ·t, respectively, yield k 0－30 k 30－60 and overall k 0－60 ;t 90 Defined as the shortest time to reach R(t) ≥ 90%, t is given by PFO fitting. 90 =2.3026 / k app The results showed that, at the same dose and total duration, simultaneous administration of the drug resulted in a higher overall apparent rate k. 0－60 With response time t 90 All of these are superior to any sequential sequential process (see Tables 8 and 9); t 90 Compared to the "IL first → magnetic second / magnetic second → IL first" method, the time was shortened by approximately 47% and 48% (26 min vs 49 / 50.5 min), respectively. Furthermore, the removal rate at the 60-minute endpoint, R≈98.4%, was higher than that of the series system (95.6–96.0%). This indicates that the performance improvement is not a linear summation of "sequential splicing" and that synchronous use has unpredictable kinetic advantages.

[0088] Table 8. Time-Removal Rate of Three Processes (Mean ± RSD, n = 3; 1:10; 100 mg·L⁻¹) －1 ; 40℃; pH 7)

[0089]

[0090] Note: The total dose and total treatment time for all three processes are the same (60 min); the "sequential" process is divided into 30 min + 30 min segments, and the time in the table is the total time.

[0091] Table 9 Rate constant and t 90 Comparison (PFO fitting R) 2 ≥0.95)

[0092]

[0093] Example 8: Effect of surface modification strategy on combined removal performance (1:10; 40℃; pH 7)

[0094] To compare the effects of single surface modification and bifunctionalization on the removal of PFAS by the combined system, under uniform experimental conditions (magnetic Fe3O4 material: ionic liquid = 1:10; 0.100 g of magnetic material and 1.000 g of ionic liquid were used),

[0095] Add [EMIM]BF4 to 100.0 mL of PFAS standard solution (100 mg / L). －1 (40℃, pH 7, 60 min), Fe3O4@SiO2-APTES (monoamine), Fe3O4@SiO2-F (monofluorine) and...

[0096] Fe3O4@SiO2-APTES-F (bifunctionalized), the remaining steps are the same as in Example 5 (after treatment, the magnetic material is separated and recovered from the treatment liquid by an applied magnetic field, and the supernatant is filtered at 0.22μm and measured by LC–MS / MS); the results show (see Table 10) that the bifunctionalized formulation and IL combination performed best, with a removal rate of 98.5±2.6%, which is significantly higher than that of monoamine 93.1±2.9% and monofluorine 88.6±3.1% (mean ± RSD, n=3). Under the same IL dosage and operating conditions, it showed an unexpected synergistic gain, which is consistent with the synergistic index η>1 in Example 2.

[0097] Table 10 Effect of different surface modifications on removal rate

[0098]

[0099] Example 9: Application Validation of Textile Pretreatment (Real Sample; 1L Scale-up; 1:10)

[0100] In the textile sample pretreatment verification, select cotton / polyester / nylon any base material cutting about 5g sample, first in 100mg·L －1 PFAS standard solution for 30min, dry to constant weight and room temperature for 12h (simulation of fixation), and then in 1.000L treatment tank to establish a combined system: add functionalized magnetic material Fe3O4@SiO2-APTES-F 0.500g and ionic liquid [EMIM]BF4 5.000g (magnetic material: IL = 1:10), 100mg·L －1 treatment solution, 40℃, pH 7, 60min stirring (or circulating flow); after treatment, separate and recover the magnetic material from the treatment solution by external magnetic field, filter the supernatant with 0.22μm, and then measure the residual PFAS by LC-MS / MS, and the result is C0=100mg·L －1 , C=9.78mg·L －1 , removal rate R=90.2%±3.8 (n=3); compared with the standard solution system (about 98%), it is slightly lower, which is consistent with the expected matrix interference and mass transfer limitation, and is consistent with the conclusion of the significant reduction of the above-mentioned matrix effect.

Claims

1. A sample pre-treatment method for textile PFAS detection, characterized in that, The method comprises the following steps: (1) preparing a treatment system: adding an ionic liquid (IL) into a treatment solution and adjusting the pH to 4-11, and controlling the temperature to be 10-55℃; (2) combined contact: adding a magnetic Fe3O4 material bifunctionalized by 3-aminopropyltriethoxysilane (APTES) and fluorine-containing silane into the treatment system, so that the mass ratio of the magnetic Fe3O4 material to the ionic liquid is 1:4-1:20, and a textile sample containing PFAS is contacted with the treatment system for 30-90 min; (3) magnetic separation: after the treatment is completed, an external magnetic field is applied to separate and recover the magnetic Fe3O4 material from the treatment solution; (4) supernatant collection: collecting the supernatant after the separation as a to-be-tested solution, or further purifying the supernatant and then using it for subsequent detection.

2. The sample pre-treatment method for textile PFAS detection according to claim 1, characterized in that, In the step (1), the pH is adjusted to 6-8, and the temperature is controlled to be 30-45℃.

3. The sample pre-treatment method for textile PFAS detection according to claim 1 or 2, characterized in that, The magnetic Fe3O4material is obtained by co-precipitation of FeCl3-6H2O and FeCl2-4H2O in a ratio of Fe 3+ : Fe 2+ ≈ 2: 1 and silanization of the obtained Fe3O4.

4. The sample pre-treatment method for textile PFAS detection according to claim 3, characterized in that, The bifunctionalization of the silane is performed in an anhydrous ethanol / water = 95 / 5 (v / v) system at 60-80℃, and the obtained material is Fe3O4@SiO2-APTES-F, and the addition amount of APTES is 5%-15% of the mass of the magnetic Fe3O4 material, and the addition amount of fluorine-containing silane is 2%-10%.

5. The sample pre-treatment method for textile PFAS detection according to claim 4, characterized in that, The ionic liquid is selected from the group consisting of 1-alkyl-3-methylimidazolium salts with BF4 － , TfO － or NTf2 － anions.

6. The sample pre-treatment method for textile PFAS detection according to claim 5, characterized in that, The mass ratio of the magnetic Fe3O4 material to the ionic liquid is 1:6-1:

12.

7. The sample pre-treatment method for textile PFAS detection according to claim 6, characterized in that, When the pH is 9-11, the ionic liquid is paired with TfO － or NTf2 － 1-alkyl-3-methylimidazolium salts of an anion.

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