Fe3O4@SiO2@PAMAM-G2 nanocomposite as sorbent for the extraction and preconcentration of estradiol valerate drug from human plasma samples

Extraction improvement of ionic liquid-functionalized silica by in situ anion-exchange for online solid-phase extraction of estrogens in honey

The accurate detection of analytes in honey is affected by the complex substrates, making it crucial to employ an effective sample preparation technique. In this work, an imidazolium ionic liquid was functionalized to the silica surface by a click reaction for solid-phase extraction (SPE) column, and in situ anion-exchange process was performed with different organic anions (dodecyl sulfonate, dodecyl benzene sulfonate, and naphthalene sulfonate). These SPE columns were evaluated through extracting the estrogens. The naphthalene sulfonate-based SPE column displayed the best extraction ability among these, and it was combined with high-performance liquid chromatography-diode array detection to establish an online enrichment and analysis system. Under the optimal test conditions, an online analytical method was developed, with high enrichment factors (1872-4744), wide linear ranges (0.0033-1.50, 0.0165-1.50, and 0.0330-1.50 μg g-1), and low detection limits (0.001-0.010 μg g-1). The method successfully determined several estrogens in some honey samples, and achieved satisfactory recovery results.

Fe3O4 supported [Cu(ii)(met)(pro-H)2] complex as a novel nanomagnetic catalytic system for room temperature C-O coupling reactions

In this study, a newly-designed copper(ii) complex of metformin and l-proline which was immobilized on Fe₃O₄ MNPs was developed. The structure of the catalyst platform was fully characterized using spectroscopic analyses. Moreover, the catalytic activity of [Fe₃O₄@Cu(ii)(Met)(Pro-H)₂] was investigated in a one-pot synthesis of a variety of functionalized ethers in reasonable to excellent yields through Ullman reaction in an aqueous environment using various aryl halides, phenol, and Cs₂CO₃ and without using any external Cu-reducing agents. Notably, gentle catalytic conditions, quick reaction times, applicability, low cost, and preventing dangerous chemicals and solvents during synthesis and catalytic application are some of the superior properties of the [Fe₃O₄@Cu(ii)(Met)(Pro-H)₂] complex. Furthermore, the catalyst can be reused for several runs (at least eight times) without remarkable loss in efficiency.

A novel and capable supported phenylazophenylenediamine-based nano-adsorbent for removal of the Pb, Cd, and Ni ions from aqueous solutions

Herein, we report the synthesis and characterization of chrysoidine (4-phenylazo-m-phenylenediamine) grafted on magnetic nanoparticles (Fe₃O₄@SiO₂@CPTMS@PhAzPhDA = FeSiPAPDA) as a novel and versatile adsorbent used for the satisfactory removal of Pb, Ni, and Cd ions from contaminated water via the formation of their complexes. The Freundlich, Langmuir, Temkin, and Redlich-Patterson isotherm models were studied to reveal the adsorption capability of the adsorbent and were found out that the Langmuir model is more compatible with the nano-adsorbent behavior. Moreover, according to the ICP tests as well as based on the Langmuir isotherm, the maximum adsorption capacity of the FeSiPAPDA-based adsorbent for the Pb ions (97.58) is more than that of Cd (78.59) and Ni ions (64.03).

Highly efficient and simultaneous magnetic solid phase extraction of heavy metal ions from water samples with l-Cysteine modified magnetic polyamidoamine dendrimers prior to high performance liquid chromatography

Due to the strong metal-sulfur interaction between mercapto groups and metal ions, which can be used to functionalize polyamidoamine dendrimer decorated Fe₃O₄ nanoparticles for high enrichment of trace heavy metal ions from waters. Based on this concept, polyamidoamine dendrimer modified Fe₃O₄ nanomaterials were functionalized with l-Cysteine and a new magnetic solid phase extraction for rapid adsorption and separation of Hg²⁺, Pb²⁺, Co²⁺ and Cd²⁺ from waters was established. The factors affecting extraction efficiency have been optimized. Upon the optimal parameters, the established method provided good linear ranges of 0.1-200 μg L^-1 for Hg²⁺ and 0.05-200 μg L^-1 for Pb²⁺, Co²⁺ and Cd²⁺, and high sensitivity with limits of detection (LOD) of 0.018 μg L^-1, 0.014 μg L^-1, 0.013 μg L^-1 and 0.025 μg L^-1 for Cd²⁺, Pb²⁺, Co²⁺ and Hg²⁺, respectively. Real water samples were utilized to validate the proposed method, and achieved results revealed that the proposed method was sensitive, effective, stable and suitable for monitoring Pb²⁺, Cd²⁺, Co²⁺and Hg²⁺ in environmental waters. This work provided a novel strategy for the simultaneous analysis of target cations in waters, and a new direction for developing decoration method of nanomaterials according to specific purpose.

Fe3O4@SiO2@VAN Nanoadsorbent Followed by GC-MS for the Determination of Polycyclic Aromatic Hydrocarbons at Ultra-Trace Levels in Environmental Water Samples

In the present study, silica-coated magnetic nanoparticles functionalized with vancomycin (Fe₃O₄@SiO₂@VAN) were synthesized. The Fe₃O₄@SiO₂@VAN nanocomposite was used as a sorbent for the magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) from environmental water, followed by GC-MS. The nanocomposite was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, and nitrogen sorption. Various experimental parameters were optimized, including extraction condition and desorption condition. Results show that Fe₃O₄@SiO₂@VAN combined the advantages of nanomaterials and magnetic separation technology, showing excellent dispersibility and high selectivity for PAHs in environmental water sample. Under the optimal extraction conditions, an analytical method was established with the sensitive limit of detection (LOD) of 0.03-0.16 μg L^-1. The method was successfully applied for the analysis of environmental water samples. The relative standard deviations (%) were in the range of 0.50-12.82%, and the extraction recovery (%) was in the range of 82.48% and 116.32%. MSPE-coupled gas chromatography-mass spectrometry quantification of PAHs is an accurate and repeatable method for the monitoring of PAH accumulation in environmental water samples. It also provides an effective strategy for the tracing and quantification of other environmental pollutants in complex samples.

Hercynite silica sulfuric acid: a novel inorganic sulfurous solid acid catalyst for one-pot cascade organic transformations

Herein, we delignated the synthesis of a novel inorganic sulfurous magnetic solid acid catalyst by the immobilization of an extremely high content of sulfuric acid functionalities on the amorphous silica-modified hercynite nanomagnetic core–shell via a simple method. Silica sulfuric acid (SSA) modified hercynite nanocomposite (hercynite@SSA) combines excellent recoverability and stability characteristics of hercynite (which can be regarded as a ferro spinel with Fd3m space group and cubic crystal structure) with the strong Brønsted acid properties of –SO₃H groups. This nanomagnetic solid acid was found to be an efficient and facile strong solid acid catalyst for the synthesis of bis(pyrazolyl)methanes via two different one-pot multicomponent methodologies under green conditions. The hercynite@SSA catalyst shows excellent catalytic activity and reusability in the ethanolic medium among different solid acid materials. A plausible reaction mechanism is proposed for this synthesis.

A novel inorganic sulfurous nanomagnetic solid acid composite was synthesized and its catalytic activity was evaluated in the synthesis of bis(pyrazolyl)methane derivatives. The catalyst displayed excellent activity and recoverability under green conditions.