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A novel magnetic, structured (with ordered pores) and hybrid imprinted polymer (HMMIP) was synthesized to selectively adsorb volatile fatty acids (VFAs) from aqueous matrices. Usual characterization techniques showed that a mesoporous adsorbent was obtained with relatively low specific areas but that could selectively (imprinting factor of 1.64) remove isovaleric acid (used as template) from aqueous solutions and effluents containing VFAs with a good capacity (Qe ~ 50 mg g−1). From kinetic studies a pseudo‐nth‐order model showed the best fit to the experimental data and resulted in kn = 3 equal to 8 × 10−4 g mg−1 min−1 whereas thermodynamic studies indicated that the adsorption of isovaleric acid onto HMMIP was endothermic and entropically driven. Reuse studies indicated that HMMIP loaded with VFA could be efficiently regenerated with acetone–water solution which led to an adsorption loss of ca 10% after three regeneration/reuse cycles and that the magnetic and specific adsorbent could be removed from complex matrices with an efficiency of ca 77%. Biochemical methane production assays showed that the addition of HMMIP to anaerobic batch reactors increased by four times the methane production due to the selective adsorption of VFAs. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Simultaneous extraction of basic, acidic and neutral compounds is an important goal in sample preparation. In this study, dispersive solid‐phase microextraction of three analyte types was carried out in a single step. The target compounds: aniline, phenol and naphthalene with surfactant modified magnetic graphene oxide sheets, before gas chromatography with flame ionization detection. The dispersive solid‐phase microextraction performed in both cationic and anionic modes by cetyltrimethylammonium bromide and sodium dodecyl sulfate respectively. First, the analytes were vortexed and adsorbed then the supernatant was decanted with a magnet and the sorbent was eluted with the proper solvent. The linearity was obtained over a wide concentration range; 0.044–0.50, 0.043–0.50 and 0.027–0.25 µg/mL for aniline, phenol and naphthalene respectively in both modes. The limit of detection and the limit of quantitation for target analytes were 0.008 –0.02 and 0.027–0.067 µg/mL, respectively in both modes. The method relative standard deviations for the analytes (0.1 µg/mL conc.) were ranged from 4.0 to 10.9% (n = 10). Enrichment factors ranged from 60 to 373. The method was successfully evaluated to simultaneously extract three different types of analytes (basic, acidic and neutral) from water samples. The recoveries ranged from 90.0 to 100.0%. [ABSTRACT FROM AUTHOR]

Abstract: Functional polymers with a metal–coordination interaction have been fabricated for sample pretreatment. Poly(N‐4‐vinyl‐benzyl iminodiacetic acid‐co‐methacrylic acid‐co‐styrene)‐modified magnetic nanoparticles were prepared and used as solid‐phase extraction adsorbents for the analysis of quinolones by tuning the metal–coordination interaction. In the construction of the polymer‐based adsorbents, functional monomer (N‐(4‐vinyl)‐benzyl iminodiacetic acid) and comonomers (methacrylic acid and styrene) were fabricated onto the magnetic nanoparticles by free radical polymerization. Factors affecting the performance of the adsorbents were investigated, and the results revealed that Fe3+ played a vital role in the formation of metal–coordination adsorbents. Compared with other compounds, the resultant adsorbents displayed good selectivity to quinolones due to the metal–coordination complex (N‐4‐vinyl‐benzyl iminodiacetic acid‐Fe3+‐quinolones). Interestingly, the captured quinolones could be rapidly released by manipulating the metal–coordination interaction with Cu2+. The linearity range for analysis of the test quinolones was 0.025–2.0 μg/mL (R2 > 0.999), and the recovery varied from 80.0 to 100.7%. Further, the proposed adsorbents were combined with high‐performance liquid chromatography for the analysis of quinolones in real urine samples. The results demonstrated that the prepared adsorbents have good selectivity and sensitivity for quinolones, showing great potential for drug analysis in real samples. [ABSTRACT FROM AUTHOR]

Preparation of polyethyleneimine functionalized magnetic Fe3O4 by using a one-step solvothermal method is reported in this paper. The effect of the amount of polyethyleneimine on the properties of the prepared materials including the shape, size, and adsorption performance was investigated in detail. The magnetic adsorbent with the best adsorption capacity was prepared and used for the removal of Pb(II) in an aqueous medium. Adsorption experiments were performed to evaluate the effect of different sorption parameters, such as pH, initial concentration of Pb2+, and contact time. Langmuir and pseudo-second-order models were used for isotherm and kinetic studies, through which a maximum adsorption capacity of 143 mg g−1 could be calculated. Pb(II) could be desorbed from magnetic Fe3O4 nanoparticles modified with polyethyleneimine by 0.5 mol L−1 HCl and used for five cycles without any adsorption performance loss, indicating that the polymeric magnetic adsorbent used in this work had good reusability and great potential for practical application. [ABSTRACT FROM AUTHOR]

Magnetic particles modified with a dicationic polymeric ionic liquid are described as a new adsorbent in magnetic solid-phase extraction. They were obtained through the copolymerization of a 1,8-di(3-vinylimidazolium)octane-based ionic liquid with vinyl-modified SiO2@Fe3O4, and were characterized by FTIR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. The modified magnetic particles are effective in the extraction of organophosphate pesticides and polycyclic aromatic hydrocarbons. Also, they can provide different extraction performance for the selected analytes including fenitrothion, parathion, fenthion, phoxim, phenanthrene, and fluoranthene, where the extraction efficiency is found to be in agreement with the hydrophobicity of analytes. Various factors influencing the extraction efficiency, such as, the amount of adsorbent, extraction, and desorption time, and type and volume of the desorption solvent, were optimized. Under the optimized conditions, a good linearity ranging from 1-100 μg/L is obtained for all analytes, except for parathion (2-200 μg/L), where the correlation coefficients varied from 0.9960 to 0.9998. The limits of detection are 0.2-0.8 μg/L, and intraday and interday relative standard deviations are 1.7-7.4% ( n = 5) and 3.8-8.0% ( n = 3), respectively. The magnetic solid-phase extraction combined with high-performance liquid chromatography can be applied for the detection of trace targets in real water samples with satisfactory relative recoveries and relative standard deviations. [ABSTRACT FROM AUTHOR]

A novel triethylenetetramine-functionalized magnetic graphene oxide composite was prepared and used as a magnetic solid-phase extraction adsorbent for the fast detection of ten trace-level phenolic environmental estrogens in environmental water. The synthesized material was carefully characterized by scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, and X-ray photoelectron spectroscopy to confirm the structure and components. The adsorption and desorption conditions of the adsorbent toward phenolic environmental estrogens were optimized in detailed to obtain the best extraction recovery and elution efficiency. Under the optimum conditions, the limits of detection of the method for ten phenolic environmental estrogens were in range of 0.15-1.5 ng/L, which was lower than the reported methods for phenolic environmental estrogens detection in literatures. This could be contributed to the unique structure and property of the as-prepared material. The developed method was successfully applied for the determination of environmental water samples with recoveries ranging from 88.5 to 105.6%. [ABSTRACT FROM AUTHOR]

A novel 3 D-graphene (3 D- G) magnetic nanomaterial was prepared and used as an adsorbent for the extraction of four neonicotinoid insecticides (acetamiprid, imidacloprid, thiacloprid, and thiamethoxam) from lemon juice sample. Then, HPLC with UV detection was applied for the determination of the neonicotinoid insecticides desorbed from the 3 D- G magnetic nanomaterial. The main experimental parameters that affect the extraction efficiencies such as the amount of 3 D- G magnetic nanomaterial, sample solution pH, extraction time, salting-out effect, and desorption conditions were studied and optimized. As a result, the linear concentration range of the method was from 0.3 to 100.0 ng/mL for thiacloprid, from 0.5 to 100.0 ng/mL for imidacloprid and acetamiprid, and from 1.0 to 100.0 ng/mL for thiamethoxam, with correlation coefficients of 0.9965-0.9985, respectively. The LODs of the method based on an S/ N of 3 were between 0.08 and 0.2 ng/mL. The enrichment factors obtained were between 67 and 427, and the RSDs ( n = 6) were in the range from 4.6 to 7.1%, and the recoveries of the method fell in the range of 88.75 to 111.60%. [ABSTRACT FROM AUTHOR]