Home Facile synthesis of core–shell structured magnetic Fe3O4@SiO2@Au molecularly imprinted polymers for high effective extraction and determination of 4-methylmethcathinone in human urine samples
Article Open Access

Facile synthesis of core–shell structured magnetic Fe3O4@SiO2@Au molecularly imprinted polymers for high effective extraction and determination of 4-methylmethcathinone in human urine samples

  • Fangsheng Wu , Zihua Zhang , Wei Liu , Yuan Liu , Xiujuan Chen , Pingyong Liao , Qiaoying Han , Lun Song EMAIL logo , Hong Chen EMAIL logo and Wenbin Liu EMAIL logo
Published/Copyright: May 20, 2022
Download Article (PDF)
Become an author with De Gruyter Brill
Submit Manuscript Author Information
e-Polymers
From the journal e-Polymers Volume 22 Issue 1

Abstract

In this study, a novel material of core–shell structured magnetic molecularly imprinted polymers (Fe3O4@SiO2@Au (FSA)-MIPs) was successfully prepared for the rapid and selective determination of 4-methylmethcathinone (mephedrone, 4-MMC). The adsorption capacity of FSA-MIPs is 34.7 mg·g−1 at 308 K, which is significantly higher than magnetic non-imprinted polymers profiting from the imprinting effect. The FSA-MIPs have a short equilibrium (20 min) and could be reused more than six times. Moreover, the selectivity coefficients of FSA-MIPs for 4-MMC, 3,4-dimethylmethcathinone, butylone, 4-ethylmethcathinone, acetylfentanyl, and methylene blue are 4.01, 5.65, 7.62, 12.30, and 20.87 respectively, further indicating the markedly enhanced binding selectivity of FSA-MIPs. As an adsorbent, the FSA-MIPs were successfully applied for effective extraction of 4-MMC in three human urine samples with the recovery rates ranging from 85.5–92.6%. The results confirmed that the FSA-MIPs have good prospects in the extraction and separation of synthetic cathinones, which is suitable for further application in the criminal sciences field.

Keywords: core–shell; magnetic molecularly imprinted polymers; 4-methylmethcathinone; extraction; separation

1 Introduction

New psychoactive substances (NPSs), also commonly called designer drugs, have been used as recreational drugs of abuse or misuse that can have intensely stimulating, calming, and psychedelic effects on the central nervous system of people (1,2). To circumvent legal regulations, these NPSs are sold mainly as “bath salts” or “plant food” and labeled as “not for human consumption” on marketing (3). NPSs may pose a major threat to public health and safety such as drug-facilitated crimes and traffic accidents of drug-drive. Synthetic cathinones are typical NPSs as they can produce psychostimulant effects with a similar structure to the classically abused drug amphetamine (4). 4-Methylmethcathinone (4-MMC), appeared in the European recreational drugs market since 2007, is a common type of synthetic cathinones whose abuse poses great challenges to human health and public services (5,6). In forensic laboratories, some specialized analytical strategies have been developed to identify and detect drugs and suspected liquid samples including gas chromatography-mass spectrometry (GC-MS) (7), liquid chromatography-mass spectrometry (LC-MS) (8,9), and high-performance liquid chromatography (HPLC) (10), and spectroscopic techniques (11–13). Although these methods show the high sensitivity and selectivity that is needed to analyze complex samples, they are limited due to expensive instruments, high cost, time-consuming, and complicated pretreatment procedures. Therefore, the development of rapid and simple alternative green methods for the separation of synthetic cathinones from aqueous solutions remains crucial.

Molecular imprinting is an effective technique that can create specific recognition sites that are chemically and sterically complementary in shape, size, and functionality to the template molecules in polymer networks (14). Due to its “memory” effect, molecularly imprinted polymers (MIPs) have been demonstrated to show high recognition and adsorption ability for the template compounds. Therefore, MIPs have been widely utilized in chemical sensors (15), drug delivery (16), solid-phase extraction (17), and adsorption materials for sample pretreatment (18). Ying et al. developed an imprinted electro-spun fiber membrane for the detection of volatile organic acids (19). Chen et al. prepared a magnetic molecularly imprinted polymer (monocrystalline iron oxide nanocompound (MION)-MIP) for the recognition and extraction of sulfadiazine (20). Zhao et al. designed and synthesized a novel functional monomer N-(1-(2,4-difluorophenyl)-2-(1H-1,2,4-triazol-1-yl)ethyl)acrylamide to adsorb for Ni(ii) in the solution containing Ni(ii) which was obtained through optimizing various affecting parameters (21). These materials of adsorption are effective and environmentally friendly, which has been widely used in the field of sample treatment in recent years. However, despite its potential, almost all of the MIPs prepared by the conventional technique still suffer from some shortcomings such as inefficient template removal, low adsorption capacity, slow mass transfer, poor site availability, irregular shape, or heterogeneous distribution of binding sites, which limit the usability of MIPs in practical applications (22). Moreover, Murakami et al. developed the MIP-SPE method using the AFFINILUTE cartridge for extraction of 11 synthetic cathinones from urine samples (23). Fu et al. synthesized a series of MIPs as selective SPE sorbents for the determination of cathinones in river water (24). The prepared MIPs are economical and effective but they mostly fail to show high adsorption capacity and outstanding selectivity. Thus, to resolve the aforementioned shortcomings, in recent years, researchers have focused on the combination of MIPs and magnetic materials which possess the obvious advantages of sample pretreatment, possible reuse, low resistance to mass transfer, large specific surface area, and fast separation. It can also maximize the use of imprinting sites and improve the efficiency of imprinting. Also, to improve the adsorption capacity and reduce the equilibrium time, nano/micro solid supports including SiO2, porous materials, carbon nanotubes, and gold nanoparticles (NPs) are used for MIPs on their surfaces by the surface imprinted techniques (14,25–27). Accordingly, in the synthesis of surface molecular imprinting polymers, an excellent carrier plays a vital role. As for these magnetic materials, Fe3O4 has already received significant research attention for mag-MIP synthesis because of its low toxicity, easy preparation (28,29). However, the bare Fe3O4 magnetic materials exhibit very strong aggregation affinity and are easily oxidized in air. In recent years, the combination of Fe3O4 magnetic materials with SiO2 has faultlessly overcome the above imperfection. Noteworthily, SiO2 is also regarded as an ideal adsorbent because of its large surface areas and tunable pore sizes (30). Meanwhile, Au NPs have attracted great interest, which not only possess predominant electronic, optical, and light absorption ability but also has excellent biocompatibility and chemical stability (31,32). It is often an effective strategy to combine the mid-layer of amino-modified SiO2 with Au NPs, and results in good dispersion and near-infrared (NIR) responses. So, magnetic Fe3O4@SiO2@Au nanospheres might be an ideal carrier for monitoring the adsorption activity of mag-MIP (33). To the best of our knowledge, few studies have reported the fabrication of mag-MIP using Fe3O4@SiO2@Au nanospheres as a support for the extraction and determination of synthetic cathinones by HPLC or ultraviolet–visible spectroscopy (UV-vis) spectrometer, which is an interesting topic and might attain some concerns from researchers in the criminal sciences fields.

In this study, the main purpose is to develop a simple and effective way combining the selectivity to the target molecule 4-MMC and the rapid magnetic response that can be easy to separate the material from the sample. For this purpose, a MIP layer is coated on Fe3O4@SiO2@Au nanospheres. The detailed structures of the obtained samples were characterized, and the main parameters including selectivity, adsorption capacity, reusability, static adsorption, and kinetic adsorption were also evaluated in detail. Finally, the FSA-MIPs were directly used as an adsorbent for the extraction of 4-MMC in human samples, followed by HPLC determination. These obtained results reveal that the excellent magnetic response and binding specificity provide promising application prospects to the novel FSA-MIPs.

2 Experimental

2.1 Materials and reagents

4-Methylmethcathinone (4-MMC), 3,4-dimethylmethcathinone (3,4-DMMC), butylone (βk-MBDB), 4-ethylmethcathinone (4-EMC), and acetylfentanyl (AF) were provided by the Shanghai Research Institute of Criminal Science and Technology. Ferric chloride hexahydrate (FeCl3·6H2O), sodium acetate (NaAc·3H2O), sodium citrate (C6H5Na3O7), gold(iii) chloride hydrate (HAuCl4·3H2O), methacrylic acid (MAA), 2,2-azobisbutyronitrile (AIBN), ethylene dimethacrylate (EGDMA), absolute ethanol, tetraethyl orthosilicate (TEOS), 3-aminopropyltriethoxysilane (APTES), methylene blue (MB), and acetic acid were all purchased from Shanghai Titanchem Co., Ltd (China). Ethylene glycol, ammonium hydroxide (NH3·H2O), and sodium lignosulfonate (SLS) were acquired from Sinopharm Chemical Reagent Ltd (China). Hydrochloric acid, potassium hydroxide, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate were bought from Aladdin Reagent Co. Ltd (China). The above-mentioned chemicals were of analytical grade and have been directly used as received without further purification. Ultrapure water of 18.2 MΩ·cm−1 of resistivity was obtained using a Milli-Q water purification system (Millipore, USA).

2.2 Instruments and characterizations

The crystalline structures of the samples were identified by using powder X-ray diffraction patterns (XRD, Rigaku, Ultima IV, Japan), with Cu Kα radiation (λ = 0.154 Å). The morphologies of samples were described by field emission scanning electron microscopy with an energy dispersive spectrometer (EDS, Zeiss Gemini 300, Germany). The chemical valence states of the samples were determined by X-ray photoelectron spectroscopy (XPS; K-Alpha system, USA). Fourier transform infrared spectroscopy (FTIR) was obtained on a Frontier infrared spectrometer (PerkinElmer, USA) to confirm the chemical structure change. The magnetic properties were performed by hysteresis loops measured under a hysteresis curves tester (vibrating sample magnetometer (VSM): Lakeshore 7400, USA). Thermo gravimetric analysis (TGA) was carried out from 30°C to 800°C with a heating rate of 10°C·min−1 under nitrogen environment by using a TGA 4000 Thermal Analyzer (PerkinElmer, USA). UV-Vis adsorption spectra were recorded by a Lambda 365 spectrometer (PerkinElmer, USA).

2.3 Materials preparation

2.3.1 Synthesis of magnetic Fe3O4 nanoparticles

The magnetic Fe3O4 NPs were synthesized by a modified solvothermal reaction. Briefly, 3.24 g of FeCl3·6H2O and 4.0 g of NaAc·3H2O were dissolved in 60 mL of ethylene glycol and stirred evenly. Then, 1.0 g of sodium citrate and 0.2 g of SLS were added into the mixture and stirred vigorously for 20 min. The obtained homogeneous yellow solution was transferred into a Teflon-lined stainless autoclave. The autoclave was sealed and kept at 200°C for 8 h and then cooled down to room temperature. The obtained Fe3O4 NPs were rinsed several times with ultrapure water and methanol successively to remove residues and then dried under vacuum at 60°C.

2.3.2 Synthesis of NH2-modified Fe3O4@SiO2 nanospheres

Typically, 200 mg of Fe3O4 were dispersed in a mixture of 30 mL of deionized water/ethanol (1:7, v/v). Then, 1 mL of ammonium hydroxide was added with stirring until a mixture solution is formed. Meanwhile, 0.3 mL of TEOS was injected into the mixed solution and stirred mechanically for 1 h under an N2 atmosphere. After that, 0.3 mL of TEOS and 0.3 mL of APTES were consecutively dropped into the mixture, followed by stirring at a constant temperature for 5 h. The NH2-modified Fe3O4@SiO2 nanospheres were collected and rinsed with ultrapure water and ethanol several times and dried in a vacuum oven for further use.

2.3.3 Preparation of Fe3O4@SiO2@Au nanospheres

For the preparation of Fe3O4@SiO2@Au nanospheres, 150 mg of NH2-modified Fe3O4@SiO2 NPs were dispersed in 35 mL of deionized water under vigorous stirring for 1 h, followed by adding 1 mL of 1 wt% HAuCl4 aqueous solution. Next, 15 mL of 50 mM NaBH4 solution was slowly dropped into the mixture, and the resultant mixture was allowed to react for another 1 h. The obtained Fe3O4@SiO2@Au nanospheres were collected by a magnet and washed with ultrapure water and ethanol several times, and finally dried in a vacuum oven.

2.3.4 Preparation of Fe3O4@SiO2@Au-MIPs

The Fe3O4@SiO2@Au-MIPs were prepared according to the literature (18,34). Typically, 100 mg of Fe3O4@SiO2@Au, 10 mg of 4-MMC, and 50 mg of MAA were dispersed successively in 10 mL of acetonitrile under an nitrogen (N2) atmosphere, and the resulting mixture was stirred vigorously for 5 h to prepare the pre-assembly solution. Subsequently, 198.2 mg of EGDMA and 10 mg of AIBN were added to the pre-assembly solution. The solution was heated to reflux, with polymerized at 60°C for 24 h, and further aged at 70°C for 24 h under N2 atmosphere. The litchi-like Fe3O4@SiO2@Au-MIPs (designated as FSA-MIPs) were magnetically separated and then sequentially washed repeatedly with methanol-acetic acid (9:1, v/v) solution until the template was no longer detected in the extraction media by UV-vis spectrometer. Following the same procedures, the Fe3O4@SiO2@Au-NIPs (designated as FSA-non-imprinted polymer (NIPs)) were also achieved but in the absence of the template.

2.3.5 Adsorption experiments

The static adsorption experiments of FSA-MIPs (or FSA-NIPs) for 4-MMC were evaluated as follows. Typically, 10 mg of FSA-MIPs (or FSA-NIPs) was dispersed in a series of 5 mL PBS (pH = 6.0) solutions with various initial concentrations of 4-MMC ranging from 5 to 100 mg·L−1. After that, the above mixtures were mechanically shaken with 150 rpm·min−1 for 6 h at three different temperatures (298, 308, and 318 K), followed by centrifugation of the suspensions and filtration of the supernatants through 0.22 μm membranes, and concentrations of which were measured using UV-vis spectrometer. Meanwhile, the binding kinetics tests were also carried out following a similar procedure by monitoring the temporal amounts of 4-MMC in the PBS solutions of different incubation times (5–120 min, pH = 6.0, C (4-MMC) = 60 mg·L−1). The adsorption capacity of 4-MMC adsorbed by the FSA-MIPs (or FSA-NIPs) was calculated by the following equation:

(1) Q e = ( C 0 − C e ) V m

(2) Q t = ( C 0 − C t ) V m

where Q e and Q t (mg·g−1) are the equilibrium and temporal adsorption amounts of 4-MMC adsorbed by the FSA-MIPs (or FSA-NIPs), respectively; C 0, C e, and C t (mg·L−1) represent the initial, equilibrium, and temporal adsorption concentrations in the solutions, respectively; V (mL) is the total volume of the adsorption mixture and m (mg) denotes the mass of the FSA-MIPs (or FSA-NIPs) used.

Moreover, the selectivity experiments of FSA-MIPs and FSA-NIPs were investigated at 308 K by using 60 mg·L−1 of 4-EMC, 3,4-DMMC, and βk-MBDB, AF, and MB in 5 mL PBS solutions as the competitors, respectively. The operating conditions were consistent with the static adsorption tests, and the results can be evaluated by imprinting factor (α) and selectivity coefficient (k), which was calculated as follows (35):

(3) K d = Q e C e

(4) k = K d ( 4 -MMC ) K d ( ana )

(5) α = K d(FSA-MIPs) K d(FSA-NIPs)

where Q e and C e stand for the equilibrium adsorption capacity and concentration. K d(4-MMC) and K d(ana) (mL·g−1) represent the partition coefficients of the FSA-MIPs and FSA-NIPs toward 4-MMC and the analogs, respectively. K d(FSA-MIPs) and K d(FSA-NIPs) are the partition coefficients of the FSA-MIPs and FSA-NIPs toward the adsorbed samples, separately.

2.4 Stability and reusability

To evaluate the stability and reusability of the FSA-MIPs, we further performed six times adsorption-desorption cycles using the same process as the static adsorption experiment. Briefly, after equilibrium, the FSA-MIPs saturated with 4-MMC were collected by centrifugation, and the residual supernatant was measured by UV-Vis spectrometer. The above FSA-MIPs were eluted by a mixture of methanol/acetic acid (9:1, v/v) to remove the template, dried in a vacuum, and reused for the next adsorption experiment. Finally, the capacity retention can be obtained as follows (36):

(6) R = C i − C n C i × 100 %

where R and C i (mg·L−1) are the capacity retention and the initial concentration of 4-MMC (namely 60 mg·L−1), respectively. C n (mg·L−1) is the concentration of 4-MMC in the supernatant after repeated experiments, and n is the number of times the experiments were repeated (n = 1, 2, 3, 4, 5, and 6).

2.5 Determination of 4-MMC in human urine

The human urine samples were provided by healthy staff as a blank sample. First, the urine samples were centrifuged for 10 min at 5,000 rpm. The liquid supernatant was filtered with a 0.22 μm membrane for extraction. About 20 mg of FSA-MIPs was added into 5.0 mL methanol and was continuously stirred for 10 min. The solution was centrifuged, and the supernatant was discarded. The treated FSA-MIPs were added into 5.0 mL 4-MMC urine spiked samples (40–400 μg·L−1) and were continuously shaken for 1 h. Then, the solution was centrifuged and washed with ultrapure water, the analyte targets were collected from the FSA-MIPs, which have been rinsed five times with methanol. The eluent was blow-dried with nitrogen. The residues were then redissolved in 200 mL of methanol and further analysis was performed by HPLC spectrometer at 280 nm.

3 Results and discussion

3.1 Fabrication of the FSA-MIPs

The synthesis steps of FSA-MIPs or the 4-MMC extraction and determination are illustrated in Scheme 1. The FSA-MIPs were prepared using Fe3O4@SiO2@Au as a supporter, MAA as a functional monomer, EGDMA as a cross-linker, and 4-MMC as a template. After the polymerization process, imprinted layers were gradually formed and uniformly dispersed on the surface of Fe3O4@SiO2@Au. Then, the imprinted product was washed with methanol-acetic acid (9:1, v/v) solution to entirely remove 4-MMC and dried under vacuum to obtain core–shell structured magnetic FSA-MIPs, which are like litchi. The FSA-MIPs were used as an adsorbent for extraction and determination of 4-MMC, which is mainly attributed to the shape and size of the imprinted sites.

Scheme 1 Schematic of the synthesis steps of FSA-MIPs and for the 4-MMC extraction and determination.
Scheme 1

Schematic of the synthesis steps of FSA-MIPs and for the 4-MMC extraction and determination.

3.2 Characterization of the FSA-MIPs and FSA-NIPs

To investigate the combination of all the as-obtained samples, XRD patterns were collected in Figure 1a. The main diffraction peaks of FSA-MIPs at 30.2°, 35.7°, 43.2°, 57.0°, and 62.9° are assigned to the (220), (311), (400), (511), and (440) specific lattice planes of Fe3O4 (37), which is consistent with a cubic spinel phase (Joint Committee on Poder Diffraction Standards (JCPDS) 75-0033) according to the pattern of Fe3O4 (38). Compared with Fe3O4, the XRD pattern of Fe3O4@SiO2 shows almost a similar feature, indicating that the crystal structure of Fe3O4 is well-maintained after the coating process of SiO2 (39). As expected, the Fe3O4@SiO2@Au, FSA-MIPs, and FSA-NIPs keep all the characteristic diffraction peaks of Fe3O4. Moreover, three obvious peaks belonging to the face-centered cubic structure of Au (JCPDS 89-3697) at 38.2°, 44.6°, and 64.6° indexed to (111), (200), and (220) planes, are observed. The above XRD results indicate the formation of a crystalline Fe3O4 phase in all samples. In order to confirm the functional groups and bond characterization of all the as-obtained samples, FTIR spectra were measured. As shown in Figure 1b, it reveals that the characteristic peak of Fe3O4 appears at 584 cm−1 assigned to the typical Fe–O vibration of the Fe3O4, and the peaks at 1,627 and 3,428 cm−1 are ascribed to the –OH bending vibration and stretching vibration of water molecules and –OH groups on the sample surface (40,41). In the Fe3O4@SiO2 curve, the peaks at 470 and 1,092 cm−1 are attributed to the O–Si–O bending mode and Si-O-Si asymmetric stretching mode, respectively (42,43). Specifically, the FTIR spectrum of Fe3O4@SiO2@Au is almost the same as that of Fe3O4@SiO2, due to the lack of absorption of Au in the infrared region (44). Additionally, the FTIR spectra of FSA-MIPs and FSA-NIPs clearly show that the new absorption peak at 1,731 cm−1 corresponds to the C═O stretching vibration of EGDMA, suggesting the imprinting polymers have been successfully grafted onto the surface of Fe3O4@SiO2@Au.

Figure 1 (a) X-ray diffraction patterns and (b) FTIR spectra of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@Au, FSA-MIPs, and FSA-NIPs.
Figure 1

(a) X-ray diffraction patterns and (b) FTIR spectra of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@Au, FSA-MIPs, and FSA-NIPs.

To further understand the elemental composition and chemical states of the as-prepared FSA-MIPs, XPS measurements were performed, and the results are displayed in Figure A1 (in Appendix). Fe, O, Si, Au, and C can be clearly identified from the survey spectra in Figure A1a. As depicted in Figure A1b, two binding energy peaks centered at 710.7 eV for Fe 2p3/2 and 724.6 eV for Fe 2p1/2 with a spin energy separation of 13.9 eV, which shows the typical values of Fe3+. The two deconvoluted peaks at 710.1 and 711.9 eV could be attributed to the 2p3/2 spin-orbit of peaks of Fe3+ and Fe2+, respectively. The satellite peaks located at 717.9 and 733.2 eV correspond to the presence of iron in a divalent oxidation state. In Figure A1c, the binding peaks of O 1s at 530.0, 530.8, and 532.2 eV are assigned to the characteristic electronic states of Fe–O, Si–O, and Si–O–Si, respectively. The Si 2p spectrum shown in Figure A1d shows peaks with binding energy at 102.4 and 103.7 eV are consistent with Si–Ox and Si–O2, respectively (45). Figure A1e shows that the Au 4f spectrum has two signal peaks at 83.8 and 87.5 eV with a spin energy separation of 3.7 eV, which can be well assigned to metallic Au 4f5/2 and 4f7/2, respectively, revealing the reduction of Au(iii) to Au (0) valance state (46). From the C 1s spectrum (Figure A1f), the binding energies at 284.6, 285.8, and 288.6 eV are attributed to the C–C, C–O, and C═O bonds, respectively.

In addition, thermal stabilities about the Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@Au, FSA-MIPs, and FSA-NIPs were studied by the TGA technique. As exhibited in Figure A2a, the Fe3O4 observed about 13.8% weight loss is probably due to the volatilization of physically absorbed water and residual organic solvent. The TGA curves of Fe3O4@SiO2, Fe3O4@SiO2@Au display a uniform trend towards similarly reduced. Since the Au NPs were not degradable in the heating process, the weight loss of Fe3O4@SiO2@Au is less than that of Fe3O4@SiO2 (47). As for the FSA-MIPs and FSA-NIPs, a sharp decline of 38.2% is observed, which is mainly ascribed to the decomposition of adsorbed water, silica, and imprinted polymers. The weight-loss process difference between the FSA-MIPs and FSA-NIPs may be due to the good adhesion of the polymer to the Fe3O4@SiO2@Au during the FSA-MIPs synthesis process. The magnetic properties of Fe3O4 and FSA-MIPs are characterized using the magnetization hysteresis loops, as displayed in Figure 3b. The magnetization curves of Fe3O4 and FSA-MIPs show that the saturation magnetization values are 74.5 and 50.8 emu·g−1, respectively. Compared to Fe3O4, the saturation magnetization of FSA-MIPs is compromised due to the surface coatings of Au, SiO2, and MIPs (48), but it also exhibits good dispersion in water and could be easily separated assisted by an external magnetic field, as shown in the inset of Figure A2b.

Figure 2 SEM images of (a) Fe3O4, (b) Fe3O4@SiO2, (c) Fe3O4@SiO2@Au, (d) FSA-MIPs, and (e) FSA-NIPs. (f) EDS spectrum of the FSA-MIPs.
Figure 2

SEM images of (a) Fe3O4, (b) Fe3O4@SiO2, (c) Fe3O4@SiO2@Au, (d) FSA-MIPs, and (e) FSA-NIPs. (f) EDS spectrum of the FSA-MIPs.

The morphologies and structures of the Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@Au, FSA-MIPs, and FSA-NIPs are observed by SEM, respectively. As depicted in Figure 2a, the SEM image of the Fe3O4 shows a regular spherical structure with average diameters of about 450 ± 30 nm. After salinization, the surface of Fe3O4 becomes smooth because of the wrapped SiO2 layer (Figure 2b). It can be clearly seen from Figure 2c that the surface of Fe3O4@SiO2@Au is much rougher than that of Fe3O4@SiO2, resulting from many small and highly dispersed AuNPs adsorbed onto the Fe3O4@SiO2. In addition, from Figures 2d and e, the FSA-MIPs and FSA-NIPs also exhibit a uniform appearance, but they have different particle sizes and topographic characteristics. The morphology of FSA-MIPs is more like litchi. This means that the participation of templates does play an essential role in the morphologies of imprinted polymers (49). The outside surface of the FSA-MIPs with rough gullies is caused by the surface pore structure expansion and the appearance of imprinted cavities after the elution of the template molecules, which provide enough contact area for template rebinding and generate high adsorption (50). The EDS spectrum and SEM elemental mapping results of the FSA-MIPs displayed in Figure 2f and Figure A3 are in accord with XPS spectra and further verify the uniform presence of Fe, Si, Au, C, and O.

Figure 3 (a) Adsorption isotherms of 4-MMC onto FSA-MIPs and FSA-NIPs at different temperatures, and the linear fitting curves of (b) Langmuir adsorption model, (c) Freundlich adsorption model, and (d) slips or Langmuir–Freundlich model of 4-MMC onto FSA-MIPs at different temperatures.
Figure 3

(a) Adsorption isotherms of 4-MMC onto FSA-MIPs and FSA-NIPs at different temperatures, and the linear fitting curves of (b) Langmuir adsorption model, (c) Freundlich adsorption model, and (d) slips or Langmuir–Freundlich model of 4-MMC onto FSA-MIPs at different temperatures.

3.3 Adsorption isotherms

Adsorption isotherms are usually to evaluate the adsorption performance of as-prepared adsorbent as well as the distribution of adsorbate species between the liquid and solid phase (51). So, the isothermal adsorption experiments are conducted with different initial concentrations of 4-MMC ranging from 5 to 80 mg·L−1 at three different temperatures (298, 308, and 318 K). According to Figure 3a, the adsorption capacity of FSA-MIPs and FSA-NIPs for 4-MMC increased with the increase of 4-MMC concentration. The FSA-MIPs exhibit significantly higher binding capacity compared to that of FSA-NIPs, which benefits from generated recognition sites of the FSA-MIPs through the elution process. Furthermore, it can be understood quite easily that the functional monomers are randomly distributed due to the lack of templates and that for FSA-NIPs it does not possess the imprinted sites. At higher concentrations, the enhancement of adsorption capacity slowly begins to flat, ascribing to the recognition sites for 4-MMC reaching a saturation. The maximum adsorption capacity of FSA-MIPs is more than other reports (23,24,43), indicating the FSA-MIPs have high recognition ability. In addition, to further reveal the adsorption isotherm mechanism, Langmuir (Eq. 7), Freundlich (Eq. 8), Slips or Langmuir–Freundlich (Eq. 9), and Scatchard (in Appendix) adsorption isotherm models were used to evaluate the adsorption performance of FSA-MIPs and FSA-NIPs, which can be expressed as:

(7) C e Q e = 1 Q m K L + C e Q m

(8) ln Q e = 1 n ln C e + ln K F

(9) Q e = K LF C e n 1 + α LF C e n

where C e (mg·L−1) is the concentration of 4-MMC at adsorption equilibrium, Q e (mg·g−1) and Q m (mg·g−1) represent the equilibrium adsorption capacity and maximum adsorption capacity, respectively. K L (L·mg−1) is the Langmuir constant related to the affinity of active sites. K F (mg·g−1) and n are the Freundlich constants associated with adsorption capacity and adsorption intensity, respectively. Whereas K LF, α LF, and n are the Slips constants. Figure 3b and c and Figures A5 and A6 display the comparison of Langmuir, Freundlich, Slips, or Langmuir–Freundlich and Scatchard models for 4-MMC adsorption on FSA-MIPs and FSA-NIPs by using linear regression, and the calculated parameters were listed in Table A1 (in Appendix) in detail. Due to the larger correlation coefficient R 2, the Slips or Langmuir–Freundlich model is close to the experimental data adequately, revealing that the active sites on the surfaces of FSA-MIPs and FSA-NIPs are diverse and the adsorption energy is heterogeneous (52,53). This also demonstrates monolayer adsorption and multilayer adsorption both occur in the adsorption processes of FSA-MIPs and FSA-NIPs. To a large extent, the adsorption of 4-MMC by FSA-MIPs is inclined to be monolayer adsorption, which is beneficial for the homogeneous nature of imprinted cavities (54).

3.4 Adsorption kinetics

The extended binding kinetics of 4-MMC onto FSA-MIPs and FSA-NIPs at 308 K were carried out to evaluate the adsorption efficiency. As shown in Figure 4a, the adsorption capacity of FSA-MIPs increased rapidly at the beginning 20 min, and then the increase rate gradually slows down until reaching equilibrium. In contrast, the FSA-NIPs displayed a similar tendency but at a low adsorption capacity. The possible reason for the discrepancy in adsorption capacity may be attributed to the effect of the imprinted sites in reducing mass transfer resistance (55). To study the kinetic mechanism of 4-MMC adsorption, the pseudo-first-order and the pseudo-second-order kinetic models were further applied for fitting analysis according to the following equations, and the relevant fitting parameters are illustrated in the Table A2.

(10) ln ( Q e − Q t ) = ln Q e − k 1 2.303 t

(11) t Q t = 1 k 2 Q e 2 + t Q e

where k 1 (min−1) and k 2 (g·mg−1·min−1) mean the rate constant for pseudo-first-order and pseudo-second-order kinetic models, respectively. Q e and Q t (mg·g−1) are the adsorption capacities of 4-MMC adsorbed onto the FSA-MIPs and FSA-NIPs at equilibrium and various t, respectively.

Figure 4 (a) Adsorption kinetics, (b) pseudo-first-order model, and (c) pseudo-second-order model of 4-MMC onto FSA-MIPs and FSA-NIPs at 308 K.
Figure 4

(a) Adsorption kinetics, (b) pseudo-first-order model, and (c) pseudo-second-order model of 4-MMC onto FSA-MIPs and FSA-NIPs at 308 K.

As shown in Figure 4b and c, the adsorption processes of FSA-MIPs and FSA-NIPs for 4-MMC are well fitted with the pseudo-second-order kinetic model, and the correlation coefficients R 2 are 0.997 and 0.996, respectively. While true, this also shows that the adsorption process of FSA-MIPs for 4-MMC was primarily dominated by the formulation of imprinted cavities and recognition sites inducing the chemical adsorption process (56,57). Moreover, the contribution from physisorption cannot be ignored (58).

3.5 Thermodynamic parameters

In order to evaluate the type of adsorption and the influence of temperature onto the adsorption amount of FSA-MIPs and FSA-NIPs for 4-MMC, the thermodynamic parameters (∆H θ , ∆S θ , ∆G θ ) can be evaluated by the following equations (59):

(10) Δ G θ = − R T ln K c

(11) ln K c = − Δ H θ R T − Δ S θ R

(12) Δ S θ = ( Δ H θ − Δ G θ ) T

where ∆G θ (kJ·mol−1), ∆S θ (J·mol−1·K−1), and ∆H θ (kJ·mol−1) are the standard Gibbs free energy change, standard entropy changes and standard enthalpy change, respectively. R (8.314 J·mol−1·K−1) and K c (K c = Q c/C e, L·g−1) refer to the universal gas constant and the thermodynamic equilibrium constant, respectively. T (K) is the Kelvin temperature. Considering the relationship between ∆G θ and K c, ∆H θ and ∆S θ are determined from the slope and intercept of the van’t Hoff plots of ln K c versus 1/T. The thermodynamic parameters at three different temperatures are compared as shown in Table A3. Clearly, the negative values of ∆G θ can illustrate that the process of 4-MMC adsorption onto FSA-MIPs is thermodynamically feasible and spontaneous (60). Moreover, the positive values of ∆H θ can conclude that the reaction of 4-MMC adsorption is endothermic, and the increase in temperature would benefit the adsorption. The positive values of ∆S θ can reflect an enhancement in randomness at the solid-liquid interface, indicating that FSA-MIPs possess a strong affinity to 4-MMC (61). The previous research suggested that the ∆H θ of physisorption is smaller than 40 kJ·mol−1 (62). Based on the ∆H θ , the adsorption of 4-MMC onto FSA-MIPs is a physisorption process. The discussions and results mentioned above are also accordant with that of the adsorption isotherm and kinetic analysis.

3.6 Selectivity and reusability analysis

In order to evaluate the specificity of FSA-MIPs and FSA-NIPs for adsorbing 4-MMC, the competitive adsorption experiments were carried out using the structural analogs (4-EMC, 3,4-DMMC, and βk-MBDB) and non-structural analogs (AF and MB) as comparative substrates by static adsorption. As demonstrated in Figure 5a, the FSA-MIPs possess significantly higher adsorption capacity for 4-MMC compared to that of other competitive compounds, which proves again FSA-MIPs have abundant recognition cavities with strong chemical and structural affinity towards 4-MMC. the selectivity coefficients of 4-EMC, 3,4-DMMC, βk-MBDB, AF, and MB are 4.01, 5.65, 7.62, 12.30, and 20.87, respectively, while the bound amounts of the NIPs show poor selectivity to all. Remarkably, the FSA-MIPs exhibit a relatively higher adsorption capacity for 4-EMC and 3,4-DMMC than the three remaining compounds, which is due to the similar structures to 4-MMC. The above results further confirm that the FSA-MIPs still have a satisfactory specific recognition ability for 4-MMC in complex systems.

Figure 5 (a) Adsorption selectivity of FSA-MIPs and FSA-NIPs for 4-MMC and its competitive compounds. (b) Regeneration performance of FSA-MIPs for 4-MMC.
Figure 5

(a) Adsorption selectivity of FSA-MIPs and FSA-NIPs for 4-MMC and its competitive compounds. (b) Regeneration performance of FSA-MIPs for 4-MMC.

To examine the regeneration ability of FSA-MIPs, six adsorption-desorption experiments were repeatedly performed in the same procedures. As shown in Figure 5b, the recognition ability of regenerated FSA-MIPs for 4-MMC is approximately 6.9% loss after consecutive adsorption-desorption cycles. The slight decrease in adsorption capacity is attributed to the damage of some imprinted cavities after repeated acid washing (63). In summary, the FSA-MIPs own good mechanical stability and outstanding regeneration ability.

3.7 Analysis of 4-MMC in human urine

To further evaluate the sensitivity and practicability, the FSA-MIPs were employed for the enrichment and separation of 4-MMC from real human urine samples, followed by HPLC determination. As shown in Table A4, no 4-MMC was detected in the urine from a healthy volunteer. The recovery experiments by spiking the urine samples with 4-MMC at three spiked levels of 40, 200, and 400 μg·L−1 were utilized to verify the method's accuracy. After adsorption treatment using the FSA-MIPs, the recoveries of 4-MMC in three urine samples were found to be 85.5%, 89.9%, and 92.6%, respectively. The results showed that enrichment and separation of 4-MMC in the real urine samples using the FSA-MIPs adsorbent was feasible.

4 Conclusions

In summary, we developed a facile approach for the preparation of core–shell structured magnetic FSA-MIPs adsorbent for efficiently and selectively separating 4-MMC. The detailed structural analyses by SEM, XRD, FTIR, VSM, and XPS measurements confirm that the material was successfully prepared. Combining the features of the core (Fe3O4@SiO2@Au) and surface MIPs, the FSA-MIPs not only have a rapid magnetic response for separation but also have a high adsorption capacity and satisfactory selectivity to target molecule 4-MMC. Owing to the super magnetic properties, the FSA-MIPs can be easily separated and efficiently reused from the reaction solution by an external magnet. Besides, the results of adsorption kinetics, isotherms, and thermodynamics show that the adsorption of 4-MMC by FSA-MIPs is a spontaneous and endothermic process, which agrees with the pseudo-second-order kinetic equation and Slips or Langmuir–Freundlich model. Furthermore, the FSA-MIPs be applied to selectively separate 4-MMC from real human urine samples, which shows an excellent enrichment capability and satisfactory recovery. Also, we believe the FSA-MIPs might be easily extended to the separation of other synthetic cathinones.

# These authors contributed equally to this work and should be considered as co-first authors.

tel: +86-21-22028361, fax: +86-21-22028361

  1. Funding information: This work was partially sponsored by Shanghai Scientific and Technological Innovation Project (20DZ1200100, 19DZ1201900, 19DZ1201904, and 19DZ1200400), Program of Shanghai Academic/Technology Research Leader (19XD1432700), Shanghai Rising-Star Program (19QB1405200 and 21QB1405800), Key Projects of Shanghai Science and Technology Commission (21DZ1200200), Natural Science Foundation of Shanghai (19ZR1449500, 19ZR1449400, and 21ZR1481700), which we greatly acknowledged.

  2. Author contributions: Fangsheng Wu: writing – original draft, writing – review and editing, methodology, formal analysis; Zihua Zhang and Lun Song: writing – original draft, experiment; Wei Liu and Yuan Liu: formal analysis, visualization; Xiujuan Chen, Pingyong Liao, and Qiaoying Han: project administration; Hong Chen and Wenbin Liu: resources.

  3. Conflict of interest: Authors state no conflict of interest.

Appendix

The Scatchard isotherm model was calculated using the below equation:

(A1) Q e C e = Q m K d − Q e K d

where Q e and Q m (mg·g−1) are the equilibrium adsorption capacity and maximum adsorption capacity, respectively. C e (mg·L−1) represents the concentration of 4-MMC at adsorption equilibrium. Whereas K d (mg·L−1) is the dissociation constant.

The effect of solution pH on the adsorption capacity of the FSA-MIPs and FSA-NIPs for 4-MMC was tested by adjusting solution pH over the range from 2.0 to 12.0. In Figure A4, the result shows that the adsorption capacity of FSA-MIPs increased from pH 3.0 to 6.0 and reached the maximum adsorption capacity at pH 6.0, which agrees with the basic characteristic of cathinones and our previous report. At higher pH (6.0–12.0), there is a gradual decrease observed in the adsorption capacity, mainly attributed to the restriction of the electrostatic attraction forces between 4-MMC and FSA-MIPs. An optimal pH of 6.0 was chosen for the further adsorption experiments.

Figure A1 XPS spectra of the as-prepared FSA-MIPs: (a) survey, (b) Fe 2p, (c) O 1s, (d) Si 2p, (e) Au 4f, and (f) C 1s.
Figure A1 XPS spectra of the as-prepared FSA-MIPs: (a) survey, (b) Fe 2p, (c) O 1s, (d) Si 2p, (e) Au 4f, and (f) C 1s.
Figure A1

XPS spectra of the as-prepared FSA-MIPs: (a) survey, (b) Fe 2p, (c) O 1s, (d) Si 2p, (e) Au 4f, and (f) C 1s.

Figure A2 (a) TGA curves of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@Au, FSA-MIPs, and FSA-NIPs in the range of 30–800°C. (b) The magnetic hysteresis loops of Fe3O4 and FSA-MIPs.
Figure A2

(a) TGA curves of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@Au, FSA-MIPs, and FSA-NIPs in the range of 30–800°C. (b) The magnetic hysteresis loops of Fe3O4 and FSA-MIPs.

Figure A3 (a) SEM image of FSA-MIPs, and elemental mappings of (b) Fe, (c) Si, (d) Au, (e) C, and (f) O.
Figure A3

(a) SEM image of FSA-MIPs, and elemental mappings of (b) Fe, (c) Si, (d) Au, (e) C, and (f) O.

Figure A4 Effect of pH on the adsorption capacity of the FSA-MIPs and FSA-NIPs to 4-MMC.
Figure A4

Effect of pH on the adsorption capacity of the FSA-MIPs and FSA-NIPs to 4-MMC.

Figure A5 The linear fitting curves of Scatchard adsorption model of 4-MMC onto FSA-MIPs at different temperatures.
Figure A5

The linear fitting curves of Scatchard adsorption model of 4-MMC onto FSA-MIPs at different temperatures.

Figure A6 The linear fitting curves of (a) Langmuir adsorption model, (b) Freundlich adsorption model, (c) scatchard adsorption model, and (d) slips or Langmuir–Freundlich model of 4-MMC onto FSA-NIPs at different temperatures.
Figure A6

The linear fitting curves of (a) Langmuir adsorption model, (b) Freundlich adsorption model, (c) scatchard adsorption model, and (d) slips or Langmuir–Freundlich model of 4-MMC onto FSA-NIPs at different temperatures.

Table A1

Parameters of isotherm models for the adsorption of 4-MMC onto FSA-MIPs and FSA-NIPs at different temperatures

T/K Langmuir Freundlich Scatchard Slip or Langmuir–Freundlich
Q m (mg·g−1) K L (L·mg−1) R 2 K F n R 2 Q m (mg·g−1) K d R 2 K LF α LF R 2
298 FSA-MIPs 88.39 0.7211 0.9450 2.2651 1.2933 0.9779 71.5383 38.7897 0.8963 1.8130 0.0262 0.9995
FSA-NIPs 21.64 0.4135 0.9883 0.4920 1.5674 0.9699 9.3135 30.0571 0.9559 0.3028 0.0334 0.9989
308 FSA-MIPs 118.55 0.4977 0.9799 3.2748 1.4096 0.9769 62.1708 22.9560 0.9500 2.8528 0.0326 0.9991
FSA-NIPs 35.30 0.2793 0.9903 0.7812 1.7000 0.9355 10.6879 21.5843 0.9304 0.4309 0.0443 0.9984
318 FSA-MIPs 146.07 0.4129 0.9827 4.2133 1.4640 0.9739 62.8465 17.2443 0.9499 3.7427 0.0585 0.9988
FSA-NIPs 39.92 0.2184 0.9721 0.8497 1.5569 0.9343 15.0286 26.2329 0.8758 0.3308 0.0310 0.9997
Table A2

Adsorption kinetic parameters for the adsorption of 4-MMC onto FSA-MIPs and FSA-NIPs at different temperatures

T/K Samples Pseudo-first-order Pseudo-second-order
K 1 ln Q e (mg·g−1) R 2 K 2 Q e (mg·g−1) R 2
308 FSA-MIPs 0.0608 2.9455 0.9612 0.00222 37.4251 0.9965
FSA-NIPs 0.0697 1.5253 0.9894 0.00923 7.6799 0.9973
Table A3

Thermodynamic parameters for the adsorption of 4-MMC onto FSA-MIPs and FSA-NIPs at different temperatures

Samples ΔH θ (kJ·mol−1) ΔS θ (J·mol−1·K−1) ΔG θ (kJ·mol−1)
298 K 308 K 318 K
FSA-MIPs 14.36 86.71 −16.30 −15.90 −15.92
FSA-NIPs 25.92 36.55 −14.93 −14.42 −14.24
Table A4

Recoveries of 4-MMC obtained from human urine samples

Sample Added (μg·L−1) Found (μg·L−1) Recovery (%) RSD (n = 3%)
Human urine 0 ND
40 34.2 85.5 5.3
200 179.8 89.9 4.2
400 370.4 92.6 4.6

References

(1) Lowdon JW, Eersels K, Rogosic R, Boonen T, Heidt B, Diliën H, et al. Surface grafted molecularly imprinted polymeric receptor layers for thermal detection of the new psychoactive substance 2-methoxphenidine. Sensor Actuat A. 2019;295:586–95.10.1016/j.sna.2019.06.029Search in Google Scholar

(2) Ren SF, Zeng JL, Zheng ZX, Shi HQ. Perspective and application of modified electrode material technology in electrochemical voltammetric sensors for analysis and detection of illicit drugs. Sensor Actuat A. 2021;329:112821–50.10.1016/j.sna.2021.112821Search in Google Scholar

(3) Shi JM, Nelso LS. The toxicology of bath salts: a review of synthetic cathinones. J Med Toxicol. 2012;8:33–42.10.1007/s13181-011-0193-zSearch in Google Scholar PubMed PubMed Central

(4) Miotto K, Striebel J, Cho AK, Wang C. Clinical and pharmacological aspects of bath salt use: A review of the literature and case reports. Drug Alcohol Depend. 2013;132:1–12.10.1016/j.drugalcdep.2013.06.016Search in Google Scholar PubMed

(5) Wood DM, Dargan PI. Mephedrone (4-methylmethcathinone): What is new in our understanding of its use and toxicity. Prog Neuro-Psychoph. 2012;39:227–33.10.1016/j.pnpbp.2012.04.020Search in Google Scholar PubMed

(6) McNeill L, Pearson C, Megson D, Norrey J, Watson D, Ashworth D, et al. Origami chips: development and validation of a paper-based Lab-on-a-Chip device for the rapid and cost-effective detection of 4-methylmethcathinone (mephedrone) and its metabolite, 4-methylephedrine in urine. Forensic Chem. 2021;22:100293–300.10.1016/j.forc.2020.100293Search in Google Scholar

(7) Rossi SS, Rossi S, Gregori A, Peluso G, Ripani L, Ortar G, et al. An analytical approach to the forensic identification of different classes of new psychoactive substances (NPSs) in seized materials. Rapid Commun Mass Spectrom. 2014;28:1904–16.10.1002/rcm.6969Search in Google Scholar PubMed

(8) Rago MD, Chu M, Rodda LN, Jenkins E, Kotsos A, Gerostamoulos D. Ultrarapid targeted analysis of 40 drugs of abuse in oral fluid by LC-MS/MS using carbon-13 isotopes of methamphetamine and MDMA to reduce detector saturation. Anal Bioanal Chem. 2016;408:3737–49.10.1007/s00216-016-9458-3Search in Google Scholar PubMed

(9) Namera A, Namera M, Nakamoto A, Saito T, Nagao M. Comprehensive review of the detection methods for synthetic cannabinoids and cathinones. Forensic Toxicol. 2015;33:175–94.10.1007/s11419-015-0270-0Search in Google Scholar PubMed PubMed Central

(10) Lowdon JW, Alkirkit MO, Mewis RE, Fulton D, Banks CE, Sutcliffe OB, et al. Engineering molecularly imprinted polymers (MIPs) for the selective extraction and quantification of the novel pscychoactive substance (NPS) methoxphenidine and its regioisomers. Analyst. 2018;143:2002–7.10.1039/C8AN00131FSearch in Google Scholar PubMed

(11) Andrade AFB, Mamo SK, Gonzalez-Rodriguez J. Rapid screening method for new psychoactive substances of forensic interest: electrochemistry and analytical determination of phenethylamines derivatives (NBOMe) via cyclic and differential pulse voltammetry. Anal Chem. 2017;89:1445–52.10.1021/acs.analchem.6b02426Search in Google Scholar PubMed

(12) Sanli S, Ghorbani-Zamani F, Moulahoum H, Gumus ZP, Coskunol H, Demirkol DO, et al. Application of biofunctionalized magnetic nanoparticles based-sensing in abused drugs diagnostics. Anal Chem. 2020;92:1033–40.10.1021/acs.analchem.9b04025Search in Google Scholar PubMed

(13) Fikiet MA, Khandasammy SR, Mistek E, Ahmed Y, Halamkova L, Bueno J, et al. Surface enhanced Raman ́spectroscopy: A review of recent applications in forensic science. Spectrochim Acta Part A. 2018;197:255–60.10.1016/j.saa.2018.02.046Search in Google Scholar PubMed

(14) Li WM, Chen MM, Xiong HY, Wen W, He HP, Zhang XH, et al. Surface protein imprinted magnetic nanoparticles for specific recognition of bovine hemoglobin. New J Chem. 2016;40:564–70.10.1039/C5NJ02879ESearch in Google Scholar

(15) Zhang LP, Hui Z, He SN. Preparation, characterization, and application of soluble liquid crystalline molecularly imprinted polymer in electrochemical sensor. Anal Bioanal Chem. 2020;412:7321–32.10.1007/s00216-020-02866-4Search in Google Scholar PubMed

(16) Alizadeh T, Zare M, Ganjali MR, Norouzi P, Tavana B. A new molecularly imprinted polymer (MIP)-based electrochemical sensor for monitoring 2, 4, 6-trinitrotoluene (TNT) in natural waters and soil samples. Biosens Bioelectron. 2010;25:1166–72.10.1016/j.bios.2009.10.003Search in Google Scholar PubMed

(17) Sadeghi S, Jahani M. Selective solid-phase extraction using molecular imprinted polymer sorbent for the analysis of florfenicol in food samples. Food Chem. 2013;141:1242–51.10.1016/j.foodchem.2013.04.027Search in Google Scholar PubMed

(18) Kong X, Gao R, He X, Chen L, Zhang Y. Synthesis and characterization of the core–shell magnetic molecularly imprinted polymers (Fe3O4@MIPs) adsorbents for effective extraction and determination of sulfonamides in the poultry feed. J Chromatogr A. 2012;1245:8–16.10.1016/j.chroma.2012.04.061Search in Google Scholar PubMed

(19) Ying XG, He JY, Li X. Molecularly imprinted electrospun fiber membrane for colorimetric detection of hexanoic acid. e-Polymers. 2021;21:500–10.10.1515/epoly-2021-0049Search in Google Scholar

(20) Chen L, Lee YK, Manmana Y, Tay KS, Lee VS, Rahman NA. Synthesis, characterization, and theoretical study of an acrylamide-based magnetic molecularly imprinted polymer for the recognition of sulfonamide drugs. e-Polymers. 2015;15(3):141–50.10.1515/epoly-2015-0017Search in Google Scholar

(21) Zhao L, Hu XZ, Zi FT, Liu YM, Hu DQ, Li P, et al. Preparation and adsorption properties of Ni(II) ion-imprinted polymers based on synthesized novel functional monomer. e-Polymers. 2021;21:590–605.10.1515/epoly-2021-0055Search in Google Scholar

(22) Ekmen E, Bilici M, Turan E, Tamer U, Zengin A. Surface molecularly-imprinted magnetic nanoparticles coupled with SERS sensing platform for selective detection of malachite green. Sensor Actuat B-Chem. 2020;325:128787–99.10.1016/j.snb.2020.128787Search in Google Scholar

(23) Murakami T, Iwamuro Y, Ishimaru R, Chinaka S, Hasegawa H. Molecularly imprinted polymer solid-phase extraction of synthetic cathinones from urine and whole blood samples. J Sep Sci. 2018;41:4506–14.10.1002/jssc.201800874Search in Google Scholar PubMed

(24) Fu YD, Pessagno F, Manesiotis P, Borrull F, Fontanals N, Marće RM. Preparation and evaluation of molecularly imprinted polymers as selective SPE sorbents for the determination of cathinones in river water. Microchem J. 2022;175:107100–8.10.1016/j.microc.2021.107100Search in Google Scholar

(25) Zhi K, Dong A, Yang X, Zhao Q, Zhao H, Zhang H, et al. Preparation and adsorption properties study of glucose magnetic molecularly imprinted polymers with dual functional monomers. Acta Chim Sinica. 2016;74:199–207.10.6023/A15090636Search in Google Scholar

(26) Xiao D, Dramou D, Xiong N, He H, Yuan D, et al. Development of novel molecularly imprinted magnetic solid-phase extraction materials based on magnetic carbon nanotubes and their application for the determination of gatifloxacin in serum samples coupled with high performance liquid chromatography. J Chromatogr A. 2013;1274:44–53.10.1016/j.chroma.2012.12.011Search in Google Scholar PubMed

(27) Shahar T, Sicron T, Mandler D. Nanosphere molecularly imprinted polymers doped with gold nanoparticles for high selectivity molecular sensors. Nano Res. 2017;10(3):1056–63.10.1007/s12274-016-1366-5Search in Google Scholar

(28) Wang L, Qiu F, Li J, Pan JR. Rapid and selective determination of melamine from eggs and milk based on magnetic surface molecularly imprinting technology. Anal Methods. 2017;9:6839–48.10.1039/C7AY02055DSearch in Google Scholar

(29) Cao YJ, Sheng TR, Yang Z, Huang DQ, Sheng LQ. Synthesis of molecular-imprinting polymer coated magnetic nanocomposites for selective capture and fast removal of environmental tricyclic analogs. Chem Eng J. 2021;426:128678–89.10.1016/j.cej.2021.128678Search in Google Scholar

(30) Wang ZM, Wang WD, Coombs N, Soheilnia N, Ozin GA. Graphene oxide-periodic mesoporous silica sandwich nanocomposites with vertically oriented channels. ACS Nano. 2010;4:7437–50.10.1021/nn102618nSearch in Google Scholar PubMed

(31) Liu XL, Tao YX, Mao HH, Kong Y, Shen J, Deng LH, et al. Construction of magnetic-targeted and NIR irradiation-controlled drug delivery platform with Fe3O4@Au@SiO2 nanospheres. Ceram Int. 2017;43:5061–7.10.1016/j.ceramint.2017.01.017Search in Google Scholar

(32) Luo SJ, Liu YQ, Rao HB, Wang YY, Wang XX. Fluorescence and magnetic nanocomposite Fe3O4@SiO2@Au MNPs as peroxidase mimetics for glucose detection. Analy Biochem. 2017;538:26–33.10.1016/j.ab.2017.09.006Search in Google Scholar PubMed

(33) Maximenko A, Depciuch J, Lopuszynska N, Stec M, Swiatkowska-Warkocka Z, Bayev V, et al. Fe3O4@SiO2@Au nanoparticles for MRI-guided chemo/NIR photothermal therapy of cancer cells. RSC Adv. 2020;10:26508–20.10.1039/D0RA03699DSearch in Google Scholar

(34) Chen H, Wu FS, Xu YB, Liu Y, Song L, Chen XJ, et al. Synthesis, characterization, and evaluation of selective molecularly imprinted polymers for the fast determination of synthetic cathinones. RSC Adv. 2021;11:29752–61.10.1039/D1RA01330KSearch in Google Scholar PubMed PubMed Central

(35) Sun XY, Ma RT, Chen J, Shi YP. Synthesis of magnetic molecularly imprinted nanoparticles with multiple recognition sites for the simultaneous and selective capture of two glycoproteins. J Mater Chem B. 2018;6:688–96.10.1039/C7TB03001KSearch in Google Scholar PubMed

(36) Martins RO, Gomes IC, Telles ADM, Kato L, Souza PS, Chaves AR. Molecularly imprinted polymer as solid phase extraction phase for condensed tannin determination from Brazilian natural sources. J Chromatogr A. 2020;1620:460977–86.10.1016/j.chroma.2020.460977Search in Google Scholar PubMed

(37) Fan RY, Min HY, Hong XZ, Yi QP, Liu W, Zhang QL, et al. Plant tannin immobilized Fe3O4@SiO2 microspheres: A novel and green magnetic bio-sorbent with superior adsorption capacities for gold and palladium. J Hazard Mater. 2019;364:780–90.10.1016/j.jhazmat.2018.05.061Search in Google Scholar PubMed

(38) Wang Y, Wei YY, Gao PC, Sun S, Du Q, Wang ZF, et al. Preparation of Fe3O4@PMAA@Ni microspheres towards the efficient and selective enrichment of histidine-rich proteins. ACS Appl Mater Interfaces. 2021;13:11166–76.10.1021/acsami.0c19734Search in Google Scholar PubMed

(39) Chi Y, Yuan Q, Li YJ, Tu JC, Zhao L, Li N, et al. Synthesis of Fe3O4@SiO2-Ag magnetic nanocomposite based on small-sized and highly dispersed silver nanoparticles for catalytic reduction of 4-nitrophenol. J Colloid Interf Sci. 2012;383:96–102.10.1016/j.jcis.2012.06.027Search in Google Scholar PubMed

(40) Guo XY, Mao FF, Wang WJ, Yang Y, Bai ZM. Sulfhydryl-modified Fe3O4@SiO2 core/shell nanocomposite: synthesis and toxicity assessment in vitro. ACS Appl Mater Interfaces. 2015;7:14983–91.10.1021/acsami.5b03873Search in Google Scholar PubMed

(41) Zhao L, Liu H, Wang F, Zeng L. Design of yolk-shell Fe3O4@PMAA composite microspheres for adsorption of metal ions and pH-controlled drug delivery. J Mater Chem A. 2014;2:7065–74.10.1039/C4TA00976BSearch in Google Scholar

(42) Sharma RK, Puri A, Monga Y, Adholeya A. Acetoacetanilide-functionalized Fe3O4 nanoparticles for selective and cyclic removal of Pb2 + ions from different charged wastewaters. J Mater Chem A. 2014;2:12888–98.10.1039/C4TA01815JSearch in Google Scholar

(43) Du LL, Wu YQ, Zhang XL, Zhang F, Chen XP, Cheng Z, et al. Preparation of magnetic molecularly imprinted polymers for the rapid and selective separation and enrichment of perfluorooctane sulfonate. J Sep Sci. 2017;40:2819–26.10.1002/jssc.201700157Search in Google Scholar PubMed

(44) Tian R, Chen XJ, Xu XL, Yao C. Electrocatalytic activity of core/shell magnetic nanocomposite. Anal Biochem. 2014;463:45–53.10.1016/j.ab.2014.06.019Search in Google Scholar PubMed

(45) Chen WZ, Liu XJ, Dai PQ, Chen YL, Jiang ZY. Study on optical properties of silicon oxycarbide thin films prepared by RF magnetron sputtering. Adv Mater Res. 2012;482–484:1307–12.10.4028/www.scientific.net/AMR.482-484.1307Search in Google Scholar

(46) Xavier PL, Chaudhari K, Verma PK, Palc SK, Pradeep T. Luminescent quantum clusters of gold in transferrin family protein, lactoferrin exhibiting FRET. Nanoscale. 2010;2:2769–76.10.1039/c0nr00377hSearch in Google Scholar PubMed

(47) Liu GQ, Wang DA, Zhou F, Liu WM. Electrostatic self-assembly of Au nanoparticles onto thermosensitive magnetic core–shell microgels for thermally tunable and magnetically recyclable catalysis. Small. 2015;11:2807–16.10.1002/smll.201403305Search in Google Scholar PubMed

(48) Kou YC, Wu T, Zheng H, Kadasala NR, Yang S, Guo CZ, et al. Recyclable magnetic MIP-based SERS sensors for selective, sensitive, and reliable detection of paclobutrazol residues in complex environments. ACS Sustain. Chem Eng. 2020;8:14549–56.10.1021/acssuschemeng.0c05065Search in Google Scholar

(49) Cui YH, Chen YH, Ding L. Fabrication of dual responsive imprinted materials of magnetic and solvent and their solvent-regulated binding performance for bisphenol A. Chem Eng J. 2021;425:131605–14.10.1016/j.cej.2021.131605Search in Google Scholar

(50) Liu WF, Liu XG, Yang YZ, Zhang Y, Xu BS. Selective removal of benzothiophene and dibenzothiophene from gasoline using double-template molecularly imprinted polymers on the surface of carbon microspheres. Fuel. 2014;117:184–90.10.1016/j.fuel.2013.09.031Search in Google Scholar

(51) Wang F, Zhang LJ, Wang YY, Liu XJ, Rohani S, Lu J. Fe3O4@SiO2@CS-TETA functionalized graphene oxide for the adsorption of methylene blue (MB) and Cu(II). Appl Surf Sci. 2017;420:970–81.10.1016/j.apsusc.2017.05.179Search in Google Scholar

(52) Xie X, Ma X, Guo L, Fan Y, Zeng G, Zhang M, et al. Novel magnetic multitemplates molecularly imprinted polymer for selective and rapid removal and detection of alkylphenols in water. Chem Eng J. 2019;357:56–65.10.1016/j.cej.2018.09.080Search in Google Scholar

(53) He P, Zhu H, Ma Y, Liu NA, Niu X, Wei M, et al. Rational design and fabrication of surface molecularly imprinted polymers based on multi-boronic acid sites for selective capture glycoproteins. Chem Eng J. 2019;367:55–63.10.1016/j.cej.2019.02.140Search in Google Scholar

(54) He Q, Liang JJ, Chen LX, Chen SL, Zheng HL, Liu HX, et al. Removal of the environmental pollutant carbamazepine using molecular imprinted adsorbents: Molecular simulation, adsorption properties, and mechanisms. Water Res. 2020;168:115164–77.10.1016/j.watres.2019.115164Search in Google Scholar PubMed

(55) Li LX, Cui Y, Ren LL, Li CY, Liu YH, Jin ZX. Magnetic dummy molecularly imprinted polymer nanoparticles as sorbent for dispersive solid-phase microextraction of phthalate monoesters in human urine samples. Microchem J. 2021;167:106266–73.10.1016/j.microc.2021.106266Search in Google Scholar

(56) Ali HR, El-Maghrabi HH, Zahran F, Moustafa YM. A novel surface imprinted polymer/magnetic hydroxyapatite nanocomposite for selective dibenzothiophene scavenging. Appl Surf Sci. 2017;426:56–66.10.1016/j.apsusc.2017.07.105Search in Google Scholar

(57) Duan FF, Chen CQ, Zhao XF, Yang YZ, Liu XG, Qin Y. Water-compatible surface molecularly imprinted polymers with synergy of bi-functional monomers forenhanced selective adsorption of bisphenol A from aqueous solution. Environ Sci-Nano. 2016;3:213–22.10.1039/C5EN00198FSearch in Google Scholar

(58) Qin Y, Liu ZC, Gao J, Dai JD, Han J, Wang Y, et al. Selective adsorption behavior of Pb(II) by mesoporous silica SBA-15-supported Pb(II)-imprinted polymer based on surface molecularly imprinting technique. J Hazard Mater. 2011;186:197–205.10.1016/j.jhazmat.2010.10.105Search in Google Scholar PubMed

(59) Hua SJ, Zhao L, Cao LY, Wang XQ, Gao JS, Xu CM. Fabrication and evaluation of hollow surface molecularly imprinted polymer for rapid and selective adsorption of dibenzothiophene. Chem Eng J. 2018;345:414–24.10.1016/j.cej.2018.03.128Search in Google Scholar

(60) Li X, Ma XG, Huang RF, Xie XW, Guo LH, Zhang MY. Synthesis of a molecularly imprinted polymer on mSiO2@Fe3O4 for the selective adsorption of atrazine. J Sep Sci. 2018;41:2837–45.10.1002/jssc.201800146Search in Google Scholar PubMed

(61) Yao YJ, Miao SD, Yu SM, Ma LP, Sun HQ, Wang SB. Fabrication of Fe3O4/SiO2 core/shell nanoparticles attached to graphene oxide and its use as an adsorbent. J Colloid Interf Sci. 2012;379:20–6.10.1016/j.jcis.2012.04.030Search in Google Scholar PubMed

(62) Kara M, Yuzer H, Sabah E, Celik MS. Adsorption of cobalt from aqueous solutions onto sepiolite. Water Res. 2003;37:224–32.10.1016/S0043-1354(02)00265-8Search in Google Scholar

(63) Cui Y, Kang WW, Qin L, Ma JH, Liu XG, Yang YZ. Magnetic surface molecularly imprinted polymer for selective adsorption of quinoline from coking wastewater. Chem Eng J. 2020;397:125480–93.10.1016/j.cej.2020.125480Search in Google Scholar
Received: 2021-12-30
Revised: 2022-02-14
Accepted: 2022-03-06
Published Online: 2022-05-20

© 2022 Fangsheng Wu et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

  1. Research Articles
  2. The effect of isothermal crystallization on mechanical properties of poly(ethylene 2,5-furandicarboxylate)
  3. The effect of different structural designs on impact resistance to carbon fiber foam sandwich structures
  4. Hyper-crosslinked polymers with controlled multiscale porosity for effective removal of benzene from cigarette smoke
  5. The HDPE composites reinforced with waste hybrid PET/cotton fibers modified with the synthesized modifier
  6. Effect of polyurethane/polyvinyl alcohol coating on mechanical properties of polyester harness cord
  7. Fabrication of flexible conductive silk fibroin/polythiophene membrane and its properties
  8. Development, characterization, and in vitro evaluation of adhesive fibrous mat for mucosal propranolol delivery
  9. Fused deposition modeling of polypropylene-aluminium silicate dihydrate microcomposites
  10. Preparation of highly water-resistant wood adhesives using ECH as a crosslinking agent
  11. Chitosan-based antioxidant films incorporated with root extract of Aralia continentalis Kitagawa for active food packaging applications
  12. Molecular dynamics simulation of nonisothermal crystallization of a single polyethylene chain and short polyethylene chains based on OPLS force field
  13. Synthesis and properties of polyurethane acrylate oligomer based on polycaprolactone diol
  14. Preparation and electroactuation of water-based polyurethane-based polyaniline conductive composites
  15. Rapeseed oil gallate-amide-urethane coating material: Synthesis and evaluation of coating properties
  16. Synthesis and properties of tetrazole-containing polyelectrolytes based on chitosan, starch, and arabinogalactan
  17. Preparation and properties of natural rubber composite with CoFe2O4-immobilized biomass carbon
  18. A lightweight polyurethane-carbon microsphere composite foam for electromagnetic shielding
  19. Effects of chitosan and Tween 80 addition on the properties of nanofiber mat through the electrospinning
  20. Effects of grafting and long-chain branching structures on rheological behavior, crystallization properties, foaming performance, and mechanical properties of polyamide 6
  21. Study on the interfacial interaction between ammonium perchlorate and hydroxyl-terminated polybutadiene in solid propellants by molecular dynamics simulation
  22. Study on the self-assembly of aromatic antimicrobial peptides based on different PAF26 peptide sequences
  23. Effects of high polyamic acid content and curing process on properties of epoxy resins
  24. Experiment and analysis of mechanical properties of carbon fiber composite laminates under impact compression
  25. A machine learning investigation of low-density polylactide batch foams
  26. A comparison study of hyaluronic acid hydrogel exquisite micropatterns with photolithography and light-cured inkjet printing methods
  27. Multifunctional nanoparticles for targeted delivery of apoptin plasmid in cancer treatment
  28. Thermal stability, mechanical, and optical properties of novel RTV silicone rubbers using octa(dimethylethoxysiloxy)-POSS as a cross-linker
  29. Preparation and applications of hydrophilic quaternary ammonium salt type polymeric antistatic agents
  30. Coefficient of thermal expansion and mechanical properties of modified fiber-reinforced boron phenolic composites
  31. Synergistic effects of PEG middle-blocks and talcum on crystallizability and thermomechanical properties of flexible PLLA-b-PEG-b-PLLA bioplastic
  32. A poly(amidoxime)-modified MOF macroporous membrane for high-efficient uranium extraction from seawater
  33. Simultaneously enhance the fire safety and mechanical properties of PLA by incorporating a cyclophosphazene-based flame retardant
  34. Fabrication of two multifunctional phosphorus–nitrogen flame retardants toward improving the fire safety of epoxy resin
  35. The role of natural rubber endogenous proteins in promoting the formation of vulcanization networks
  36. The impact of viscoelastic nanofluids on the oil droplet remobilization in porous media: An experimental approach
  37. A wood-mimetic porous MXene/gelatin hydrogel for electric field/sunlight bi-enhanced uranium adsorption
  38. Fabrication of functional polyester fibers by sputter deposition with stainless steel
  39. Facile synthesis of core–shell structured magnetic Fe3O4@SiO2@Au molecularly imprinted polymers for high effective extraction and determination of 4-methylmethcathinone in human urine samples
  40. Interfacial structure and properties of isotactic polybutene-1/polyethylene blends
  41. Toward long-live ceramic on ceramic hip joints: In vitro investigation of squeaking of coated hip joint with layer-by-layer reinforced PVA coatings
  42. Effect of post-compaction heating on characteristics of microcrystalline cellulose compacts
  43. Polyurethane-based retanning agents with antimicrobial properties
  44. Preparation of polyamide 12 powder for additive manufacturing applications via thermally induced phase separation
  45. Polyvinyl alcohol/gum Arabic hydrogel preparation and cytotoxicity for wound healing improvement
  46. Synthesis and properties of PI composite films using carbon quantum dots as fillers
  47. Effect of phenyltrimethoxysilane coupling agent (A153) on simultaneously improving mechanical, electrical, and processing properties of ultra-high-filled polypropylene composites
  48. High-temperature behavior of silicone rubber composite with boron oxide/calcium silicate
  49. Lipid nanodiscs of poly(styrene-alt-maleic acid) to enhance plant antioxidant extraction
  50. Study on composting and seawater degradation properties of diethylene glycol-modified poly(butylene succinate) copolyesters
  51. A ternary hybrid nucleating agent for isotropic polypropylene: Preparation, characterization, and application
  52. Facile synthesis of a triazine-based porous organic polymer containing thiophene units for effective loading and releasing of temozolomide
  53. Preparation and performance of retention and drainage aid made of cationic spherical polyelectrolyte brushes
  54. Preparation and properties of nano-TiO2-modified photosensitive materials for 3D printing
  55. Mechanical properties and thermal analysis of graphene nanoplatelets reinforced polyimine composites
  56. Preparation and in vitro biocompatibility of PBAT and chitosan composites for novel biodegradable cardiac occluders
  57. Fabrication of biodegradable nanofibers via melt extrusion of immiscible blends
  58. Epoxy/melamine polyphosphate modified silicon carbide composites: Thermal conductivity and flame retardancy analyses
  59. Effect of dispersibility of graphene nanoplatelets on the properties of natural rubber latex composites using sodium dodecyl sulfate
  60. Preparation of PEEK-NH2/graphene network structured nanocomposites with high electrical conductivity
  61. Preparation and evaluation of high-performance modified alkyd resins based on 1,3,5-tris-(2-hydroxyethyl)cyanuric acid and study of their anticorrosive properties for surface coating applications
  62. A novel defect generation model based on two-stage GAN
  63. Thermally conductive h-BN/EHTPB/epoxy composites with enhanced toughness for on-board traction transformers
  64. Conformations and dynamic behaviors of confined wormlike chains in a pressure-driven flow
  65. Mechanical properties of epoxy resin toughened with cornstarch
  66. Optoelectronic investigation and spectroscopic characteristics of polyamide-66 polymer
  67. Novel bridged polysilsesquioxane aerogels with great mechanical properties and hydrophobicity
  68. Zeolitic imidazolate frameworks dispersed in waterborne epoxy resin to improve the anticorrosion performance of the coatings
  69. Fabrication of silver ions aramid fibers and polyethylene composites with excellent antibacterial and mechanical properties
  70. Thermal stability and optical properties of radiation-induced grafting of methyl methacrylate onto low-density polyethylene in a solvent system containing pyridine
  71. Preparation and permeation recognition mechanism of Cr(vi) ion-imprinted composite membranes
  72. Oxidized hyaluronic acid/adipic acid dihydrazide hydrogel as cell microcarriers for tissue regeneration applications
  73. Study of the phase-transition behavior of (AB)3 type star polystyrene-block-poly(n-butylacrylate) copolymers by the combination of rheology and SAXS
  74. A new insight into the reaction mechanism in preparation of poly(phenylene sulfide)
  75. Modified kaolin hydrogel for Cu2+ adsorption
  76. Thyme/garlic essential oils loaded chitosan–alginate nanocomposite: Characterization and antibacterial activities
  77. Thermal and mechanical properties of poly(lactic acid)/poly(butylene adipate-co-terephthalate)/calcium carbonate composite with single continuous morphology
  78. Review Articles
  79. The use of chitosan as a skin-regeneration agent in burns injuries: A review
  80. State of the art of geopolymers: A review
  81. Mechanical, thermal, and tribological characterization of bio-polymeric composites: A comprehensive review
  82. The influence of ionic liquid pretreatment on the physicomechanical properties of polymer biocomposites: A mini-review
  83. Influence of filler material on properties of fiber-reinforced polymer composites: A review
  84. Rapid Communications
  85. Pressure-induced flow processing behind the superior mechanical properties and heat-resistance performance of poly(butylene succinate)
  86. RAFT polymerization-induced self-assembly of semifluorinated liquid-crystalline block copolymers
  87. RAFT polymerization-induced self-assembly of poly(ionic liquids) in ethanol
  88. Topical Issue: Recent advances in smart polymers and their composites: Fundamentals and applications (Guest Editors: Shaohua Jiang and Chunxin Ma)
  89. Fabrication of PANI-modified PVDF nanofibrous yarn for pH sensor
  90. Shape memory polymer/graphene nanocomposites: State-of-the-art
  91. Recent advances in dynamic covalent bond-based shape memory polymers
  92. Construction of esterase-responsive hyperbranched polyprodrug micelles and their antitumor activity in vitro
  93. Regenerable bacterial killing–releasing ultrathin smart hydrogel surfaces modified with zwitterionic polymer brushes
https://doi.org/10.1515/epoly-2022-0034
Keywords for this article
core–shell; magnetic molecularly imprinted polymers; 4-methylmethcathinone; extraction; separation
Creative Commons
BY 4.0

Articles in the same Issue

  1. Research Articles
  2. The effect of isothermal crystallization on mechanical properties of poly(ethylene 2,5-furandicarboxylate)
  3. The effect of different structural designs on impact resistance to carbon fiber foam sandwich structures
  4. Hyper-crosslinked polymers with controlled multiscale porosity for effective removal of benzene from cigarette smoke
  5. The HDPE composites reinforced with waste hybrid PET/cotton fibers modified with the synthesized modifier
  6. Effect of polyurethane/polyvinyl alcohol coating on mechanical properties of polyester harness cord
  7. Fabrication of flexible conductive silk fibroin/polythiophene membrane and its properties
  8. Development, characterization, and in vitro evaluation of adhesive fibrous mat for mucosal propranolol delivery
  9. Fused deposition modeling of polypropylene-aluminium silicate dihydrate microcomposites
  10. Preparation of highly water-resistant wood adhesives using ECH as a crosslinking agent
  11. Chitosan-based antioxidant films incorporated with root extract of Aralia continentalis Kitagawa for active food packaging applications
  12. Molecular dynamics simulation of nonisothermal crystallization of a single polyethylene chain and short polyethylene chains based on OPLS force field
  13. Synthesis and properties of polyurethane acrylate oligomer based on polycaprolactone diol
  14. Preparation and electroactuation of water-based polyurethane-based polyaniline conductive composites
  15. Rapeseed oil gallate-amide-urethane coating material: Synthesis and evaluation of coating properties
  16. Synthesis and properties of tetrazole-containing polyelectrolytes based on chitosan, starch, and arabinogalactan
  17. Preparation and properties of natural rubber composite with CoFe2O4-immobilized biomass carbon
  18. A lightweight polyurethane-carbon microsphere composite foam for electromagnetic shielding
  19. Effects of chitosan and Tween 80 addition on the properties of nanofiber mat through the electrospinning
  20. Effects of grafting and long-chain branching structures on rheological behavior, crystallization properties, foaming performance, and mechanical properties of polyamide 6
  21. Study on the interfacial interaction between ammonium perchlorate and hydroxyl-terminated polybutadiene in solid propellants by molecular dynamics simulation
  22. Study on the self-assembly of aromatic antimicrobial peptides based on different PAF26 peptide sequences
  23. Effects of high polyamic acid content and curing process on properties of epoxy resins
  24. Experiment and analysis of mechanical properties of carbon fiber composite laminates under impact compression
  25. A machine learning investigation of low-density polylactide batch foams
  26. A comparison study of hyaluronic acid hydrogel exquisite micropatterns with photolithography and light-cured inkjet printing methods
  27. Multifunctional nanoparticles for targeted delivery of apoptin plasmid in cancer treatment
  28. Thermal stability, mechanical, and optical properties of novel RTV silicone rubbers using octa(dimethylethoxysiloxy)-POSS as a cross-linker
  29. Preparation and applications of hydrophilic quaternary ammonium salt type polymeric antistatic agents
  30. Coefficient of thermal expansion and mechanical properties of modified fiber-reinforced boron phenolic composites
  31. Synergistic effects of PEG middle-blocks and talcum on crystallizability and thermomechanical properties of flexible PLLA-b-PEG-b-PLLA bioplastic
  32. A poly(amidoxime)-modified MOF macroporous membrane for high-efficient uranium extraction from seawater
  33. Simultaneously enhance the fire safety and mechanical properties of PLA by incorporating a cyclophosphazene-based flame retardant
  34. Fabrication of two multifunctional phosphorus–nitrogen flame retardants toward improving the fire safety of epoxy resin
  35. The role of natural rubber endogenous proteins in promoting the formation of vulcanization networks
  36. The impact of viscoelastic nanofluids on the oil droplet remobilization in porous media: An experimental approach
  37. A wood-mimetic porous MXene/gelatin hydrogel for electric field/sunlight bi-enhanced uranium adsorption
  38. Fabrication of functional polyester fibers by sputter deposition with stainless steel
  39. Facile synthesis of core–shell structured magnetic Fe3O4@SiO2@Au molecularly imprinted polymers for high effective extraction and determination of 4-methylmethcathinone in human urine samples
  40. Interfacial structure and properties of isotactic polybutene-1/polyethylene blends
  41. Toward long-live ceramic on ceramic hip joints: In vitro investigation of squeaking of coated hip joint with layer-by-layer reinforced PVA coatings
  42. Effect of post-compaction heating on characteristics of microcrystalline cellulose compacts
  43. Polyurethane-based retanning agents with antimicrobial properties
  44. Preparation of polyamide 12 powder for additive manufacturing applications via thermally induced phase separation
  45. Polyvinyl alcohol/gum Arabic hydrogel preparation and cytotoxicity for wound healing improvement
  46. Synthesis and properties of PI composite films using carbon quantum dots as fillers
  47. Effect of phenyltrimethoxysilane coupling agent (A153) on simultaneously improving mechanical, electrical, and processing properties of ultra-high-filled polypropylene composites
  48. High-temperature behavior of silicone rubber composite with boron oxide/calcium silicate
  49. Lipid nanodiscs of poly(styrene-alt-maleic acid) to enhance plant antioxidant extraction
  50. Study on composting and seawater degradation properties of diethylene glycol-modified poly(butylene succinate) copolyesters
  51. A ternary hybrid nucleating agent for isotropic polypropylene: Preparation, characterization, and application
  52. Facile synthesis of a triazine-based porous organic polymer containing thiophene units for effective loading and releasing of temozolomide
  53. Preparation and performance of retention and drainage aid made of cationic spherical polyelectrolyte brushes
  54. Preparation and properties of nano-TiO2-modified photosensitive materials for 3D printing
  55. Mechanical properties and thermal analysis of graphene nanoplatelets reinforced polyimine composites
  56. Preparation and in vitro biocompatibility of PBAT and chitosan composites for novel biodegradable cardiac occluders
  57. Fabrication of biodegradable nanofibers via melt extrusion of immiscible blends
  58. Epoxy/melamine polyphosphate modified silicon carbide composites: Thermal conductivity and flame retardancy analyses
  59. Effect of dispersibility of graphene nanoplatelets on the properties of natural rubber latex composites using sodium dodecyl sulfate
  60. Preparation of PEEK-NH2/graphene network structured nanocomposites with high electrical conductivity
  61. Preparation and evaluation of high-performance modified alkyd resins based on 1,3,5-tris-(2-hydroxyethyl)cyanuric acid and study of their anticorrosive properties for surface coating applications
  62. A novel defect generation model based on two-stage GAN
  63. Thermally conductive h-BN/EHTPB/epoxy composites with enhanced toughness for on-board traction transformers
  64. Conformations and dynamic behaviors of confined wormlike chains in a pressure-driven flow
  65. Mechanical properties of epoxy resin toughened with cornstarch
  66. Optoelectronic investigation and spectroscopic characteristics of polyamide-66 polymer
  67. Novel bridged polysilsesquioxane aerogels with great mechanical properties and hydrophobicity
  68. Zeolitic imidazolate frameworks dispersed in waterborne epoxy resin to improve the anticorrosion performance of the coatings
  69. Fabrication of silver ions aramid fibers and polyethylene composites with excellent antibacterial and mechanical properties
  70. Thermal stability and optical properties of radiation-induced grafting of methyl methacrylate onto low-density polyethylene in a solvent system containing pyridine
  71. Preparation and permeation recognition mechanism of Cr(vi) ion-imprinted composite membranes
  72. Oxidized hyaluronic acid/adipic acid dihydrazide hydrogel as cell microcarriers for tissue regeneration applications
  73. Study of the phase-transition behavior of (AB)3 type star polystyrene-block-poly(n-butylacrylate) copolymers by the combination of rheology and SAXS
  74. A new insight into the reaction mechanism in preparation of poly(phenylene sulfide)
  75. Modified kaolin hydrogel for Cu2+ adsorption
  76. Thyme/garlic essential oils loaded chitosan–alginate nanocomposite: Characterization and antibacterial activities
  77. Thermal and mechanical properties of poly(lactic acid)/poly(butylene adipate-co-terephthalate)/calcium carbonate composite with single continuous morphology
  78. Review Articles
  79. The use of chitosan as a skin-regeneration agent in burns injuries: A review
  80. State of the art of geopolymers: A review
  81. Mechanical, thermal, and tribological characterization of bio-polymeric composites: A comprehensive review
  82. The influence of ionic liquid pretreatment on the physicomechanical properties of polymer biocomposites: A mini-review
  83. Influence of filler material on properties of fiber-reinforced polymer composites: A review
  84. Rapid Communications
  85. Pressure-induced flow processing behind the superior mechanical properties and heat-resistance performance of poly(butylene succinate)
  86. RAFT polymerization-induced self-assembly of semifluorinated liquid-crystalline block copolymers
  87. RAFT polymerization-induced self-assembly of poly(ionic liquids) in ethanol
  88. Topical Issue: Recent advances in smart polymers and their composites: Fundamentals and applications (Guest Editors: Shaohua Jiang and Chunxin Ma)
  89. Fabrication of PANI-modified PVDF nanofibrous yarn for pH sensor
  90. Shape memory polymer/graphene nanocomposites: State-of-the-art
  91. Recent advances in dynamic covalent bond-based shape memory polymers
  92. Construction of esterase-responsive hyperbranched polyprodrug micelles and their antitumor activity in vitro
  93. Regenerable bacterial killing–releasing ultrathin smart hydrogel surfaces modified with zwitterionic polymer brushes
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 9.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/epoly-2022-0034/html
Scroll to top button