Restricted double access ionic imprinted polymer for online extraction and determination of copper from milk samples via FIA-FAAS system

BACKGROUND

Determining metals in complex biological samples, such as milk, typically involves dry or wet decomposition. However, these techniques have limitations, including low selectivity, risk of contamination, and the use of large reagent volumes. To solve these problems, solid-phase extraction (SPE) using multifunctional sorbents has been extensively explored. In this context, this work proposed synthesizing a new restricted double access ionic imprinted polymer (RAIIP-BSA), for online SPE and determination of Cu2+ from untreated milk samples via flow injection analysis and flame atomic absorption spectrometry (FIA-FASS).

RESULTS

Firstly, the polymer was obtained by bulk polymerization using Cu2+ as a template, 4-vinyl pyridine as a functional monomer, and glycidyl methacrylate as a hydrophilic comonomer. Subsequently, it was covered with bovine serum albumin, creating the restricted double access barrier. The obtained material could exclude 97 % of the proteins from milk samples. RAIIP-BSA was chemically and physically characterized. The main extraction variables were optimized via multivariate optimization. The method showed good figures of merit, such as linearity ranging from 0.05 to 1.0 mg L-1, LoD and LoQ of 0.03 and 0.05 mg L-1, intra- and interday precision ranging from 0.73 to 4.14 % and 0.16-3.68 %, and an intra- and interday accuracy ranging from 97.0 to 115.0 % and 103.0-119.0 %, respectively.

SIGNIFICANCE

The developed method demonstrates the effective extraction of Cu2+ from untreated milk samples, exhibiting selectivity, high extraction capacity, prolonged sorbent (RAIIP-BSA) durability, simplicity, and swift operation. This method holds promise as an alternative to conventional metal analysis approaches in complex matrices.

Synthesis and evaluation of a chitosan nanomaterial as efficient sorbent for determination of fungicide residues in waters and wine by liquid chromatography high resolution mass spectrometry

In the present study a novel, cost-effective, environmentally friendly, and efficient analytical method was developed to analyze fungicide residues in water and wine. The method relies on the application of a newly developed sorbent nanomaterial named Nano-Cs-NAT, synthesized by modifying chitosan, a naturally occurring, low-cost polysaccharide, through grafting with two acrylic monomers and a cross-linker. Nano-Cs-NAT was introduced as analytical sorbent for Dispersive Micro Solid Phase Extraction (D-μ-SPE) before Liquid Chromatography-Orbitrap High-Resolution Mass Spectrometry (LC-Orbitrap HRMS) analysis of twelve fungicides commonly used in viticulture (among the others, triazoles, strobilurines and N-substituted imidazoles). Characterization of the sorbent was conducted, confirming the successful acrylation of chitosan. A multivariate approach was employed to optimize D-μ-SPE extraction parameters. The material was found to be highly effective in simultaneously purifying and concentrating the target analytes, enhancing overall analytical efficiency and sensitivity. The Nano-Cs-NAT-D-μ-SPE-LC-Orbitrap-HRMS method was thoroughly validated, exhibiting good recoveries (72-104%), reproducibility (average RSD ≤ 6%) and repeatability (average RSD ≤ 7%). It also achieved low limits of detection (LOD) in river water (average LOD of 0.04 μg L-1) and wine (average LOD of 0.72 μg kg-1), highlighting its potential for routine fungicide residue analysis. This developed method addresses environmental and food safety concerns by providing an efficient solution for detecting fungicide residues in waters and wine.

Introduction of a new and safe synthesis procedure for Ni-MOF-I in aqueous solution and its application for the extraction of some pesticides from different beverages

For the first time, this research introduces an analytical application of Ni-MOF-I, which was used as an adsorbent in a dispersive micro solid phase extraction procedure followed by dispersive liquid-liquid microextraction for the extraction and preconcentration of seven pesticides from different fruit juices. Also, Ni-MOF-I was synthesized by a new and green method with many advantages over the previously published synthesis procedures. For example, effortless and green synthesis, no need for autoclaves and ovens, and elimination of organic solvent usage are the main highlights. The synthesized Ni-MOF-I was characterized by applying nitrogen adsorption/desorption, energy-dispersive X-ray, scanning electron microscopy, Fourier transform infrared spectrophotometry, and X-ray diffraction analyses. The studied pesticides were extracted and preconcentrated by the proposed method. Then, the extracted analytes in the sedimented organic phase were injected into a gas chromatography-flame ionization detector. Acceptable analytical results such as low limits of detection (0.15-0.60 μg L-1) and quantification (0.50-2.0 μg L-1), reasonable extraction recoveries (51-80%), high enrichment factors (255-400), satisfactory relative standard deviation values of 4.8-7.2% (intra-day precision, n = 6) and 5.3-7.5% (inter-day precision, n = 4), and wide linear ranges were obtained. The proposed method can be introduced as an effective analytical technique based on Ni-MOF-I for the analysis of different pesticides in fruit beverages.

Amino-functionalized hypercrosslinked polymer as sorbent for effective extraction of nitroimidazoles from water, drink and honey samples

The three hypercrosslinked polymers (HCP) materials, designated as OPD-HCP, MPD-HCP and PPD-HCP, were synthesized by using o-phenylenediamine (OPD), m-phenylenediamine (MPD) and p-phenylenediamine (PPD) as monomers. They were characterized by infrared spectroscopy, powder X-ray diffraction, nitrogen sorption isotherms, and scanning electron microscopy. Then, the HCPs were explored as solid-phase extraction (SPE) adsorbent for the extraction of five nitroimidazoles (NDZs) (metronidazole, ronidazole, secnidazole, dimetridazole and ornidazole). Among the three HCPs, the MPD-HCP has the best adsorption performance for the NDZs. With the help of high-performance liquid chromatography with ultraviolet detection (HPLC-UV), good linear response range (0.07-40.0 ng mL^-1), high method recovery (86.8%-113.3%), low limits of detection (0.02-0.15 ng mL^-1) and good precision with the relative standard deviations of less than 8.1% were achieved for the determination of the NDZs in water samples. The effective determination of the NDZs in peach juice, honey tea, and honey samples were also realized by the developed method with satisfactory results. Based on both the experimental results and density functional theory calculation, the adsorption mechanism can be attributed to multiple interactions between the MPD-HCP and the NDZs, including hydrogen bonding, hydrophilic, and electrostatic interactions. The method provides a new alternative of choice for the determination of some NDZs in real samples.

Experimental modelling studies on the removal of dyes and heavy metal ions using ZnFe2O4 nanoparticles

The presence of dyes and heavy metals in water sources as pollutants is harmful to human and animal health. Therefore, this study aimed to evaluate the efficacy of zinc ferrite (ZnFe2O4) nanoparticles (ZF-NPs) due to their outstanding properties including cost-effectiveness, availability, and applicability for removal of auramine O (AO), methylene blue (MB), and Cd (II). The effect of the main operating parameters such as AO concentration, MB concentration, Cd (II) concentration, adsorbent amount, solution pH, and sonication time was optimized by the response surface methodology (RSM). Optimal conditions were obtained at adsorbent amount of 0.25 g, pH = 6, sonication time of 15 min, and concentration of 15 mg L-1, and more than 91.56% were removed from all three analytes. The adsorption of AO, MB, and Cd (II) onto ZF-NPs followed pseudo-second-order kinetics and the equilibrium data fitted well with Langmuir isotherm. The maximum adsorption capacities of ZF-NPs for AO, MB and Cd (II) were as high as 201.29 mg g-1, 256.76 mg g-1 and 152.48 mg g-1, respectively. Also, the reuse of the adsorbent was investigated, and it was found that the adsorbent can be used for up to five cycles. Based on the results of interference studies, it was found that different ions do not have a significant effect on the removal of AO, MB, and Cd (II) in optimal conditions. The ZF-NPs was investigated successfully to remove AO, MB, and Cd (II) from environmental water samples. The results of this study showed that ZF-NPs can be used as a suitable adsorbent to remove AO, MB, and Cd (II) from aqueous solution.

Lysosome-targeting luminescent lanthanide complexes: From molecular design to bioimaging

Lysosomes are essential acidic cytoplasmic membrane-bound organelles in human cells that play a critical role in many cellular events. A comprehensive understanding of lysosome-specific imaging can ultimately help us to...

On the use of metal-organic frameworks for the extraction of organic compounds from environmental samples

The determination of trace metals and organic contaminants in environmental samples, such as water, air, soil, and sediment, is until today a challenging process for the analytical chemistry. Metal-organic frameworks (MOFs) are novel porous nanomaterials that are composed of metal ions and an organic connector. These materials are gaining more and more attention due to their superior characteristics, such as high surface area, tunable pore size, mechanical and thermal stability, luminosity, and charge transfer ability between metals and ligands. Among the various applications of MOFs are gas storage, separation, catalysis, and drug delivery. Recently, MOFs have been successfully introduced in the field of sample preparation for analytical chemistry and they have been used for sample pretreatment of various matrices. This review focuses on the applications of MOFs as novel adsorbents for the extraction of organic compounds from environmental samples.

Highly effective pre-concentration of thymol and carvacrol using nano-sized magnetic molecularly imprinted polymer based on experimental design optimization and their trace determination in summer savoury, Origanum majorana and Origanum vulgare extracts

To ascertain thymol and carvacrol in pharmaceutical syrups, a valid and effective magnetic molecular imprinted polymer dispersive solid phase microextraction (MMIP-DSPME) process was developed in this study, which was in combination with a high performance liquid chromatography-ultra violet (HPLC-UV) technique for the assessment of thymol and carvacrol separation and pre-concentration. Contact time, eluent kind and volume, pH, the mass of the MMIP were all taken into consideration as key factors. Design expert and multi-objective response surface methodology (RSM) were used to optimize these variables. The mass of the MMIP, sample pH, eluent kind, time of sorption, the volume of eluent, and time of elution were 10 mg, 6, acetonitrile, 28 min, 200 µL, and 5.5 min, respectively, for the maximum extraction recovery of the analytes. The limit of detection (LOD) was 0.042 ng mL^-1 at the optimal conditions, while the value for the limit of quantification (LOQ) was 0.140 ng mL^-1. At the optimized conditions for thymol and carvacrol, the suggested MMIP sorbent had sorption capacities of 64.1 and 72.6 mg g^-1, respectively. Furthermore, for triplicate measurements, the linear dynamic range (LDR) was 0.40-5000 ng mL^-1, and the method's accuracy (RSD %) was 6.26%. The saturation magnetization for the MMIP was 19.0 emu g^-1 obtained by VSM, allowing the sorbent to be separated quickly. The sorption experiments confirmed the large sorption capacity of the MMIP for thymol and carvacrol, as well as its homogeneous binding sites. The extraction recovery for thymol and carvacrol was 96.9-103.8% and 96.6-105.4%, respectively, at all spiked amounts (20, 100, 200, and 500 ng mL^-1). The findings of seven desorption-regeneration cycles using MMIP demonstrated the high stability of the sorbent. The MMIP revealed a particular behavior of sorption for thymol and carvacrol, implying a selective, simple, effective, and flexible analytical method.

A Comprehensive Review on Metal Organic Framework Based Preconcentration Strategies for Chromatographic Analysis of Organic Pollutants

Organic pollutants (OPs) are of worldwide concern for being hazardous to human existence and natural flora and fauna in view of their contaminating nature, bio-aggregation properties and long range movement abilities in environment. Metal organic frameworks (MOFs) are a new kind of crystalline porous material, composed of metal ions and multi dentate organic ligands with well-defined co-ordination geometry exhibiting promising application respect to adsorptive evacuation of OPs for chromatographic analysis. Applications of MOFs as preconcentration material and column packing material are reviewed. Key analytical characteristics of MOF based preconcentration techniques and coupled chromatographic procedures are summarized in detail. MOF based preconcentration strategies are compared with conventional sorbent based extraction techniques for thorough evaluation of performance of MOF materials.

Facile Cloud Point Extraction for the Separation and Determination of Phenolic Acids from Dandelion

It is significantly crucial to develop a robust pretreatment for the quantitative analysis of herbs. However, the traditional strategies are time-consuming, tedious, and not eco-friendly. In this work, cloud point extraction (CPE) is engineered for the simultaneous separation and enrichment of ferulic acid (FA), chlorogenic acid (CLA), and caffeic acid (CA) from dandelion prior to its determination by high-performance liquid chromatography (HPLC). A famous nonionic surfactant of Triton X-114 was selected as an extractant of CPE, and parameters affecting the extraction, such as surfactant concentration, salt content, pH value, temperature, and incubation time, were investigated carefully. Furthermore, the well-designed CPE with ultrasonic assistance combined with HPLC was developed for the detection of the target analytes in dandelion. The established method having a good linearity in the range of 0.15-26.2 mg L-1 with R 2 more than 0.9979 and the spiked recoveries ranging from 81 to 96% was applied to test real samples of dandelion. The contents of CA in samples were consistent with those assayed by the method (Chinese Pharmacopoeia 2015). The proposed method afforded good analytical performances, shorter pretreatment time (65 min), and less organic solvent consumption (less than 1.0 mL). It was proved that the developed method presented a facile, inexpensive, efficient, and environment-friendly pretreatment and can be used for the quantitative analysis of CLA, CA, and FA in dandelion. As expected, the proposed method would be a promising potential for the quality analysis of herbal medicines.

Ultrasound-assisted solid phase microextraction-HPLC method based on Fe3O4@SiO2-NH2-molecularly imprinted polymer magnetic nano-sorbent for rapid and efficient extraction of harmaline from Peganum harmala extract

In the present study, a magnetic molecularly imprinted polymer (MMIP) was synthesized for the extraction of harmaline from Peganum harmala by dispersive solid-phase microextraction (DSPME). The MMIP for selective and intelligent extraction of harmaline with excellent functionality and high selectivity was synthesized using the sol-gel method with functionalized superparamagnetic core-shell nanoparticles, ethylene glycol dimethacrylate (EDMA) as a cross-linker, methacrylic acid (MAA) as a functional monomer, and 2,2-azobisisobutyronitrile (AIBN) as a porogen. To study the properties and morphology of the coated polymer, FT-IR spectroscopy, FESEM, TEM images, and VSM were used. The DSPME-HPLC-UV equipment was used to quantify and analyze the data obtained from harmaline extraction. In this research, the efficiency of the synthesized polymer in harmaline extraction was modeled and optimized using the response surface methodology based on central composite design (RSM-CCD). In addition, for modeling the isotherm of harmaline sorption by the MMIP, Langmuir and Freundlich isotherm equations were used. The obtained results showed that the extraction of harmaline with the MMIP was well described with Freundlich isotherm. The results of the validation of the method showed that the measurement of harmaline in the concentration range of 1.0-4000 ng mL^-1 followed a linear relationship (R² = 9986.0). Moreover, the accuracy or repeatability index (% RSD) was determined to be < 10, and the LOQ and LOD values were 0.526 and 0.158 ng mL^-1, respectively. The results of this study showed that the DSPME technique by using the synthesized MMIP as an effective sorbent with high efficiency and capacity could be utilized for pre-concentration and extraction of harmaline from real and complex samples.

Efficient dispersive micro solid-phase extraction of antidepressant drugs by a robust molybdenum-based coordination polymer

A molybdenum-based coordination polymer {[Mo(PDA)(NO)(μ-O)MoO₃]·1.42H₂O·0.58C₂H₅OH}_n (1) (PDA is 1,10-phenanthroline-2,9-dicarboxylate) was synthesized using solvothermal reaction conditions and characterized using a suite of analytical techniques. Single-crystal X-ray diffraction studies reveal a 1D chain structure, with close contacts expanding the structure into 3D including π-interactions and hydrogen bonding. The utility of 1 as a sorbent for dispersive micro solid-phase extraction (D-μSPE) of basic organic compounds such as antidepressants is supported by the presence of many functional groups on the surface of 1 (such as pendant carboxylates, Mo=O, Mo-NO, and CH groups) as well as extensive electrostatic interactions. Therefore, 1 can be a suitable choice as sorbent in the D-μSPE of antidepressant drugs from human plasma samples via appreciable adsorbate-adsorbent interactions. Determination of the extracted antidepressant drugs was conducted using high-performance liquid chromatography-ultraviolet (HPLC-UV), with calibration plots being linear in the concentration range 0.1-500 ng mL^-1 for amitriptyline and nortriptyline, 0.2-500 ng mL^-1 for imipramine, and 0.5-300 ng mL^-1 for sertraline. The relative standard deviation (RSD) values were calculated for both intra-day and inter-day precision, and the RSD% values were in the range 3.9 to 5.2% and 4.6-5.4%, respectively. The limits of detection (LODs) was determined as 0.03-0.2 ng mL^-1. Due to the good stability and reusability of the sorbent, the adsorption capacity had no obvious decrease after being used 20 times. Finally, the D-μSPE-HPLC-UV method was applied for the determination of antidepressant drugs in human plasma samples with recoveries of the analytes in the range 94.9 to 102%. The article describes the synthesis of a robust molybdenum-based coordination polymer, and its application as sorbent for dispersive micro solid-phase extraction of antidepressant drugs from human plasma samples.

Determination of paracetamol using a sensor based on green synthesis of silver nanoparticles in plant extract

The biosynthesis of nanometals using a plant extract is simple, efficient, fast, cost-effective and eco-friendly. In this study, a pine nut extract (Araucaria angustifolia) was obtained and used as a reducing and stabilizing agent in the synthesis of silver nanoparticles. An electrochemical sensor based on the silver nanoparticles obtained and exfoliated graphite nanoplatelets applied to a glassy carbon electrode was developed for the determination of paracetamol. To optimize the synthesis of the silver nanoparticles, important factors such as temperature, extract:water ratio, silver nitrate concentration and extract stability time were studied. The factors influencing the performance of the sensor were studied in detail and the results demonstrated good repeatability and electrode-to-electrode repeatability (relative standard deviations of 1.8 and 4.0 %, respectively). Under optimized conditions, there was a linear response to paracetamol concentrations of 4.98 × 10^-6 to 3.38 × 10^-5 mol L^-1, with a detection limit of 8.50 × 10^-8 mol L^-1. No reports on the biosynthesis of AgNPs using Araucaria angustifolia could be found in the literature. The sensor developed showed good stability and was used successfully for the quantification of paracetamol in pharmaceutical products.

Bacillus cereus liquid fertilizer was produced from Agaricus bisporus industrial wastewater

During the Agaricus bisporus canning processes, a large number of water-soluble elements were dissolved into the processing hot water. This study was conducted to use the industrial wastewater of A. bisporus to prepare agricultural microbial fertilizer. In the work, the influence of 6 different liquid fermentation factors on the total biomass of living Bacillus cereus was evaluated with the one-factor-at-a-time method and the Plackett-Burman design. The total biomass of living B. cereus was most influenced by fermentation temperature, shaking speed, and inoculation volume, which were identified as the most critical independent variables for the B. cereus biomass. The approximate ranges of optimal fermentation conditions for the three key factors were identified by the path of steepest ascent. The center point of these factors were 24 ℃ of temperature, 250 rpm of shaking speed and 12 % inoculum amount, respectively. The Box-Behnken design was applied to derive a statistical model for optimizing the three fermentation factors for B. cereus biomass. After further optimizations based on statistical predictions, the optimum fermentation parameters for B. cereus cultured in the A. bisporus industrial wastewater were fermentation temperature of 24.8 °C, shaking speed of 234 rpm, inoculum dose of 12.2 % (v:v, %), industrial wastewater concentration of 4%, initial pH values of 6.5, loading liquid of 60 mL/250 mL, and culture time of 24 h. Culturing with the optimal fermentation conditions resulted in the biomass of B. cereus of 1.35 ± 0.02 × 10⁹ Obj/mL (N = 3), which was consistent with the predicted values (1.32 × 10⁹ Obj/mL) predicted by the corresponding regression models (p < 0.05), and more, was also far higher than that of the standard of agricultural bacterial fertilizers in People's Republic of China. Further, the results of field trial indicated that the of B. cereus liquid fertilizer can remarkably enhance the yield of Brassica chinensis L. It is practicable to make use of the industrial wastewater of A. bisporus to prepare the microbial fertilizer.

Sn-MOF@CNT nanocomposite: An efficient electrochemical sensor for detection of hydrogen peroxide

A novel approach for the assembly of Sn-based metal organic framework (Sn-MOF) via solvothermal method and its composite (Sn-MOF@CNT) with electroactive material, carbon nanotubes (CNT) by sonochemical means, is described that is useful for hydrogen peroxide sensing; large surface area and pore volume of Sn-MOF were exploited where in the crystallinity of the Sn-MOF was preserved upon inclusion of CNT over its surface. The surface morphology and structural analysis of Sn-MOF and its composite form, Sn-MOF@CNT, were determined analytically through Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Brunauer-Emmett-Teller and Energy-dispersive X-ray spectroscopy (EDX). The developed Sn-MOF@CNT sensor was expansively used to determine and optimize the effect of scan rate, concentration and detection limits including the EDX and SEM analysis of used Sn-MOF@CNT nanocomposite's post hydrogen peroxide sensing. The electrochemical sensing with Sn-MOF@CNT revealed a lower limit of detection ~4.7 × 10^-3 μM with wide linear range between 0.2 μM and 2.5 mM. This study has explored a new strategy for the deposition of CNT over Sn-MOF via a simple sonochemical methodology for successful electrochemical detection of H₂O₂, an approach that can be imitated for other applications.

Introducing reticular chemistry into agrochemistry

For survival and quality of life, human society has sought more productive, precise, and sustainable agriculture. Agrochemistry, which solves farming issues in a chemical manner, is the core engine that drives the evolution of modern agriculture. To date, agrochemistry has utilized chemical technologies in the form of pesticides, fertilizers, veterinary drugs and various functional materials to meet fundamental demands from human society, while increasing the socio-ecological consequences due to inefficient use. Thus, more useful, precise, and designable scaffolding materials are required to support sustainable agrochemistry. Reticular chemistry, which weaves molecular units into frameworks, has been applied in many fields based on two cutting-edge porous framework materials, namely metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs). With flexibility in composition, structure, and pore chemistry, MOFs and COFs have shown increasing functionalities associated with agrochemistry in the last decade, potentially introducing reticular chemistry as a highly accessible chemical toolbox into agrochemical technologies. In this critical review, we will demonstrate how reticular chemistry shapes the future of agrochemistry in the fields of farm sensing, agro-ecological preservation and reutilization, agrochemical formulations, smart indoor farming, agrobiotechnology, and beyond.

A new approach for microextraction of trace albendazole sulfoxide drug from the samples of human plasma and urine, and water by the molecularly imprinted polymer nanoparticles combined with HPLC

In this research study, a method of dispersive-micro-solid phase extraction (D-µ-SPE) combined with molecularly imprinted polymer nanoparticles (MIP-NPs) with HPLC-UV was developed for the fast and selective detection of the trace amount of albendazole sulfoxide (ABZSO) in the biological samples. To investigate the effective factors on ABZSO microextraction by the method, central composite design (CCD) was utilized, and the optimum conditions for ABZSO microextraction were sample pH of 8.0, MIP-mass of 15 mg, sonication time of 12 min, and eluent (methanol) volume of 0.25 mL. Under the obtained optimal extraction conditions, the value for the limit of detection (LOD) and limit of quantification (LOQ) was respectively showed to be 0.074 and 0.246 ng mL^-1. In addition, the calculated peak areas exhibited a linear relationship with the ABZSO concentration ranging from 0.4 to 4200 ng mL^-1. The analyses of the samples including human plasma and urine, and water were successfully performed by the usage of the D-µ-SPE method, which was a simple and sensitive technique and a suitable alternative for the analysis of ABZSO. In the analysis of ABZSO in various samples, the recoveries at various levels of ABZSO concentrations (50, 300, and 500 ng mL^-1) were in the range of 95.7-103.0 %, and the relative standard deviations (RSDs; n = 3) varied from 2.2 to 4.4%.

Rapid ultrasound-assisted microextraction of atorvastatin in the sample of blood plasma by nickel metal organic modified with alumina nanoparticles

In the present work, nickel-1,4-benzenedioxyacetic acid was synthesized as a rod-like metal organic material and then modified with alumina nanoparticles to synthesize nickel metal organic modified-Al₂ O₃ nanoparticles. The material was found as an efficient sorbent for the enrichment of atorvastatin in human blood plasma. After the extraction of the sample of plasma by ultrasound-assisted dispersive solid phase extraction, high performance liquid chromatography-ultraviolet was used to determine the quantitatively pre-concentrated interest analyte. The conditions for optimum extraction were achieved by the optimization of the volume of eluent, dosage of the sorbent, and time of sonication. Solution pH of 7.0, 250 μL of ethanol, 45 mg of the sorbent, and 10 min of sonication time were the conditions for extracting the atorvastatin maximum recovery of higher than 97.0%. By using desirability function for the optimization of the process, the present method showed a response that was linear ranging from 0.2 to 800 ng/mL with regression coefficient of 0.999 in the plasma of human blood with a satisfactory detection limit of 0.05 ng/mL, while the precision of interday for the current method was found to be <5%. It can be concluded that dispersive solid phase extraction method is effective for the extraction of atorvastatin from human plasma samples (97.4-102%) due to its easy operation, simplicity, repeatability, and reliability.

Recent applications of magnetic solid phase extraction in sample preparation for phytochemical analysis

Sample preparation such as isolation and pre-concentration is a crucial step for the phytochemical analysis. Magnetic solid-phase extraction (MSPE) has received considerable attention, mainly due to its phase separation more conveniently by facile magnetic decantation as compared to traditional SPE. This review focused on the recent applications of MSPE in sample preparation for the analysis of phytochemical compounds in plants, biological samples and Chinese herbal preparations. In addition, the enzymes immobilized on the magnetic materials and used for the biospecific extraction of enzyme inhibitors were also discussed. The information summarized in this article may provide a reference to the further applications of MSPE in phytochemical analysis.

An alkaline dissolution-based method using tetramethylammonium hydroxide for metals determination in cow milk samples

This study approaches the development of a method for the determination of Ca, Mg, Zn, and Fe in liquid and powdered cow milk. The method is based on sample dissolution assisted by ultrasound energy in tetramethylammonium hydroxide (TMAH) media and determination by flame atomic absorption spectrometry (FAAS). Central composite design (CCD) associated with response surface methodology and desirability function allowed the fast and efficient optimization of the variables involved in the performance of the dissolution. The developed dissolution method allowed Ca, Fe, Zn, and Mg determination in milk samples with adequate analytical characteristics for these determinations. Addition/recovery tests and analysis of a certified reference material of skimmed powdered milk (ERM-BD150) have shown that this method presents enough accuracy to carry out these analyses.

MOFs for the treatment of arsenic, fluoride and iron contaminated drinking water: A review

Over the last few decades, the global pollution of surface and groundwater poses a serious threat not only to human beings but also towards aquatic lives due to the presence of emerging contaminants. Among the others, the presence of arsenic, fluoride, and iron are considered as the most common toxic pollutants in water bodies. The emergence of metal organic frameworks (MOFs) with high porosity and surface area is represented as significant inclusion into the era of entrapping contaminants present in drinking water. In the present review article, an in-depth insight is provided on the recent developments in the removal of arsenic, fluoride, and iron from drinking water using MOFs. Various aspects related to the synthesis, latest technologies adopted for the modifications in the synthesis process and advanced applications of MOFs for the removal of such contaminants are explicitly discussed. A detailed insight was provided to understand the mechanism of various interactions of MOFs with arsenic and fluoride. With respect to arsenic, fluoride, and iron removal the ultrastructural morphology of MOFs is assessed based on different molecular arrangements. Further, commercial aspects of various MOFs are presented in order to highlight the process feasibility. Finally, various perspectives and challenges involved in process scale up are comprehensively narrated with an aspiration of futuristic developments. The paper will be beneficial to the readers for acquiring a piece of in-depth knowledge on MOFs and its various synthesis approaches along with remarkable achievements for the removal of arsenic, fluoride, and iron from contaminated drinking water.

Biocompatible chitosan-zinc oxide nanocomposite based dispersive micro-solid phase extraction coupled with HPLC-UV for the determination of rosmarinic acid in the extracts of medical plants and water sample

In the present research, a procedure was described for the recovery of rosmarinic acid (RA) from medical extract samples using chitosan‑zinc oxide nanoparticles as a biocompatible nanocomposite (CS-ZnO-NC). The dispersive micro-solid phase extraction (D-μ-SPE) of RA from the medical extract samples was investigated by using the prepared biocompatible composite as a solid phase. The HPLC-UV method was used for measuring the extracted RA. The important variables (pH, biocompatible composite mass, contact time, and volume of eluent) associated with the extraction process were analyzed by the application of central composite design (CCD). The achieved optimum values for the mentioned variables were 7.0, 10 mg, 4 min, and 180 μL, respectively. The extraction recovery (99.68%) obtained from the predicted model was in agreement with the experimental data (98.22 ± 1.33%). In addition, under the obtained optimum conditions and over the concentration in the range of 2-3500 ng mL-1, a linear calibration curve was obtained with R2 > 0.993. The limit of detection (LOD) and quantification (LOQ) values were computed, and the obtained ranges were respectively from 0.060 to 0.089 ng mL-1 and 0.201 to 0.297 ng mL-1. In addition, the enrichment factors were obtained in the range of 93.7-110.5 with preconcentration factor of 83.3. Therefore, the D-μ-SPE-HPLC-UV method could be used for analyzing RA in the samples of the extracts obtained from the medical plants and water with the recovery values of the analyte in the range of 96.6%-105.4% and the precision with relative standard deviation <5.7%.

Protective effect of Nasturtium officinale R. Br and quercetin against cyclophosphamide-induced hepatotoxicity in rats

Cyclophosphamide (CPA) is used in the management of autoimmune conditions and malignant illnesses. However, its therapeutic use is limited because of its severe side effects, especially hepatotoxicity attributed to oxidative stress. Nasturtium officinale R. Br (watercress or WC) has pharmacological properties, such as anti-inflammation, and antioxidant activities. Therefore, the present study was design to assess effects of WC or its active ingredient, quercetin (QE), against CPA-induced hepatotoxicity. For this study, 49 male Wistar rats (200-250 g) were randomly selected and categorized into seven equal groups. The animals were pre- and post-treated with both hydroalcoholic extract of WC (500 mg/kg) and quercetin (75 mg/kg) for 10 consecutive days, and intraperitoneal administration of CPA (200 mg/kg) was performed on only day 10, one hour before the last dose of WC or quercetin. On day 11, all the animals were sacrificed, and their blood and liver were gathered for evaluation of the liver enzyme, hepatic oxidative stress markers, antioxidant enzymes activity, and hematoxylin and eosin staining. CPA significantly increased malondialdehyde (MDA), protein carbonyl (PCO) and nitric oxide (NO) levels and liver biomarkers. Otherwise, hepatic catalase (CAT), reduced glutathione (GSH), total thiol content (tSH), and ferric reducing antioxidant power (FRAP) were considerably lower than the control group. Results showed that WC has the ability to reduce the changes (MDA, PCO, FRAP, CAT, ALT and AST) and QE (MDA, PCO, AST) induced by CPA (p < 0.05). Histopathological finding confirmed the indicated results. These findings propose that WC and QE have protective effect against the CPA-induced hepatotoxicity by decreasing oxidative stress.

Magnetic Cu: CuO-GO nanocomposite for efficient dispersive micro-solid phase extraction of polycyclic aromatic hydrocarbons from vegetable, fruit, and environmental water samples by liquid chromatographic determination

In this research, we presented a magnetic dispersive micro-solid phase extraction (MD-μ-SPE) method coupled with high performance liquid chromatography (HPLC) based on the use of magnetic Cu: CuO-Graphene Oxide (GO) nanocomposite (Fe₃O₄/Cu: CuO/GO-NC) for the separation and preconcentration of polycyclic aromatic hydrocarbons (PAHs), i.e. naphthalene (Nap), phenanthrene (Phe), anthracene (Ant), and pyrene (Pyr), in vegetable (onion, tomato, carrot, herb, watermelon, lettuce, eggplant, and chili pepper), fruit (apple, watermelon, and grape), wastewater, and water samples. The MD-μ-SPE of PAHs in matrix samples was carried out, and the impacts of pH, ionic strength, extraction time, temperature, eluent volume, and sorbent mass on the recovery of PAHs were investigated by using Placket-Burman design (PBD). In addition, by using the central composite design (CCD), the best combination of each important variable was measured. Sorbent mass of 14 mg, eluent volume of 200 μL, and 12 min extraction time at the central level of other factors were optimal conditions of pretreatment for the highest extraction recovery (ER%) of trace PAHs. Under the optimal conditions, the method proposed herein provided high enrichment factors ranged from 116.51 to 133.05, good linearity in the range of 10-3800 ng mL^-1 for Pyr, 3.0-3500 ng mL^-1 for Phe, 5.0-3200 ng mL^-1 for Nap, and 5.0-3000 ng mL^-1 for Ant with coefficient of determination (R²) values between 0.9889 and 0.9963, low limits of detection (LOD) and quantification (LOQ) in the range of 0.015-0.061 and 0.485-2.034 ng mL^-1, respectively, and also satisfactory spiked recoveries (between 95.1% and 106.8%) with the relative standard deviations (RSDs) values in the range of 1.73%-5.62%. The Fe₃O₄/Cu: CuO/GO-NC-based MD-μ-SPE followed by HPLC-UV corroborated promising results for the convenient and effective determination of PAHs in the samples of vegetables, fruits, and environmental water. The results of this study revealed that our developed method is easy, feasible, precise, highly effective, and convenient to operate for the trace analysis of PAHs in different real samples. The extraction recovery was about 90% of the initial recovery after the sorbent usage for three times; therefore, the Fe₃O₄/Cu: CuO/GO-NC can readily be regenerated.

Magnetic dual-template molecularly imprinted polymer based on syringe-to-syringe magnetic solid-phase microextraction for selective enrichment of p-Coumaric acid and ferulic acid from pomegranate, grape, and orange samples

Magnetic dual-template molecularly imprinted polymer (Fe3O4@SiO2-MDMIP) was prepared to enrich and determine both p-Coumaric acid (p-CA) and ferulic acid (FA) based on syringe-to-syringe magnetic solid-phase microextraction (SS-MSPME). The obtained MDMIP was characterized and recognized, and then its adsorbing performance was studied. Based on the results, the Fe3O4@SiO2-MDMIP indicated selective recognition towards p-CA and FA with large adsorption capacity. The optimization of MDMIP-SS-MSPME conditions (pH, Fe3O4@SiO2-MDMIP mass, NaCl concentration, number of cycle, and elution volume) were conducted using the central composite design (CCD). Under the optimum conditions, an effectual and a convenient method was established to determine p-CA and FA in pomegranate, grapes, and orange samples based on SS-MSPME coupling with high-performance liquid chromatography-ultraviolet (HPLC-UV). Our developed method showed the limit of detection (LOD) of 0.08 ng mL-1 for p-CA and 0.07 ng mL-1 for FA. The method also indicated good linearity with R2 > 0.99 and good recoveries of 85.12-94.96% with RSDs ≤ 5.58% spiked at three various concentration levels in pomegranate, grapes, and orange samples.

Synthesis of novel biocomposite powder for simultaneous removal of hazardous ciprofloxacin and methylene blue: Central composite design, kinetic and isotherm studies using Brouers-Sotolongo family models

Over the past decades, extensive efforts have been made to use biomass-based-materials for wastewater-treatment. The first purpose of this study was to develop and characterize regenerated-reed/reed-charcoal (RR-ChR), an enhanced biosorbent from Tunisian-reed (Phragmites-australis). The second aim was to assess and optimize the RR-ChR use for the removal of binary ciprofloxacin antibiotic (CIP) and methylene blue dye (MB), using Central Composite Design under Response Surface methodology. The third purpose was to explain the mechanisms involved in the biosorption-process. The study revealed that the highest removal-percentages (76.66 % for the CIP and 100 % for the MB) were obtained under optimum conditions: 1.55 g/L of adsorbent, 35 mg/L of CIP, 75 mg/L of MB, a pH of 10.42 and 115.28 min contact time. It showed that the CIP biosorption mechanism was described by Brouers-Sotolongo-fractal model, with regression-coefficient (R²) of 0.9994 and a Person's Chi-square (X²) of 0.01. The Hill kinetic model better described the MB biosorption (R² = 1 and X² = 1.0E-4). The isotherm studies showed that the adsorbent surface was heterogeneous and the best nonlinear-fit was obtained with the Jovanovich (R² = 0.9711), and Brouers-Sotolongo (R² = 0.9723) models, for the CIP and MB adsorption, respectively. Finally, the RR-ChR lignocellulosic-biocomposite-powder could be adopted as efficient and cost-effective adsorbent.

A nature-inspired colorimetric and fluorescent dual-modal biosensor for exosomes detection

As non-invasive biomarkers, exosomes are of great significance to diseases diagnosis. However, sensitive and accurate detection of exosomes still remains technical challenges. Herein, inspired by nature's "one-to-many" concept, we design a biosensor mimicking the cactus with numerous thorns to detect exosomes. The biosensor is composed of CD63 antibodies, resembling the roots of cactus, to capture exosomes, and the exosomes resemble the stems. Cholesterol-labeled DNA (DNA anchor) binding to streptavidin modified horseradish peroxidase (HRP) can insert into exosomes membrane, which seems the thorns. The readout signal is produced through HRP-catalyzed hydrogen peroxide (H₂O₂) mediated oxidation of 1,4-phenylenediamine (PPD) to form 2,5-diamino-NN'-bis-(p-aminophenyl)-1,4-benzoquinone di-imine (PPDox). The PPDox can quench fluorescence of fluorescein through inner filter effect (IFE), which provides fluorescent signal for exosomes detection. Based on this principle, the obtained exosomes solution is qualitatively and quantitatively analyzed by our biosensor, with the comparison to current standard methods by nanoparticle tracking analysis (NTA) and commercial enzyme-linked immunosorbent assay (ELISA) kit. The linear range is from 1.0 × 10⁴ to 5.0 × 10⁵ particles μL^-1 with the limit of detection 3.40 × 10³ particles μL^-1 and 3.12 × 10³ particles μL^-1 for colorimetric and fluorescent assays, respectively. Meanwhile, our biosensor exhibits good selectivity, and can eliminate the interference from proteins. This dual-modal biosensor shows favorable performance towards analytical application in clinic samples, pushing one step further towards practical clinical use.

Luminescent metal organic frameworks-based chemiluminescence resonance energy transfer platform for turn-on detection of fluoride ion

A luminescent metal organic frameworks (MOFs)-based chemiluminescence resonance energy transfer (CRET) platform was constructed for turn-on detection of fluoride ion. A hybrid MOFs was prepared by encapsulating strong fluorescence 2',7'-dichlorofluorescein (DCF) into the frames of NH₂-MIL-101(Al) MOFs, which led to a significant suppression of fluorescence signal of DCF. In the presence of fluoride ion, it destroyed the structure of the hybrid MOFs and released DCF molecules from the frames due to the formation of more stable aluminum hexafluoride complex ions [AlF₆^3-] between fluoride ion and aluminum ion. The released DCF molecules accepted the energy originating from the chemical reaction of bis(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide (H₂O₂), producing a strong chemiluminescence (CL) emission. The CL signal was strong dependent on the concentration of fluoride ion presented and showed a linear response in the range of 0.5-80.0 μmol L^-1 (9.5 μg L^-1-1.52 mg L^-1). The detection limit was 0.05 μmol L^-1 (about 0.95 μg L^-1) fluoride ion and the relative standard deviations was 2.3% for 40.0 μmol L^-1 fluoride ion solution (n = 11). This MOFs-based CRET method was successfully applied to the determination of fluoride ion in drinking water samples, demonstrating its potential application in analysis of real samples.

Functional Metal Organic Framework/SiO2 Nanocomposites: From Versatile Synthesis to Advanced Applications

Metal organic frameworks (MOFs), also called porous coordination polymers, have attracted extensive attention as molecular-level organic-inorganic hybrid supramolecular solid materials bridged by metal ions/clusters and organic ligands. Given their advantages, such as their high specific surface area, high porosity, and open active metal sites, MOFs offer great potential for gas storage, adsorption, catalysis, pollute removal, and biomedicine. However, the relatively weak stability and poor mechanical property of most MOFs have limited the practical application of such materials. Recently, the combination of MOFs with inorganic materials has been found to provide a possible strategy to solve such limitations. Silica, which has excellent chemical stability and mechanical properties, shows great advantages in compounding with MOFs to improve their properties and performance. It not only provides structured support for MOF materials but also improves the stability of materials through hydrophobic interaction or covalent bonding. This review summarizes the fabrication strategy, structural characteristics, and applications of MOF/silica composites, focusing on their application in chromatographic column separation, catalysis, biomedicine, and adsorption. The challenges of the application of MOF/SiO2 composites are addressed, and future developments are prospected.

Structure-switching aptamer triggering hybridization displacement reaction for label-free detection of exosomes

Exosomes play important roles in intercellular communications, tumor migration and invasion. However, the specific detection of cancer exosomes remains as a big challenge due to its low concentration in biofluids. Therefore, the sensitive and selective detection of cancer cells-derived exosomes has attracted growing attention owing to their potential in diagnostic and prognostic applications. Activatable strategies have received great attention for the detection of low abundant analytes due to their high sensitivity. Herein, based on molecular recognition between DNA aptamer and exosome surface biomarker (protein tyrosine kinase-7), a novel activatable and label-free strategy was designed for highly sensitive and specific sensing of exosomes. In this work, the target exosomes trigger strand replacement reaction to form G-quadruplex, which result in an obvious fluorescence enhancement of N-methylmesoporphyrin IX due to the bonding between G-quadruplex and N-methylmesoporphyrin IX. Under the optimum experimental conditions, the linear range for exosomes was measured to be 5.0 × 10⁵-5.0 × 10⁷ particles/μL and the detection limit (LOD) was calculated to be 3.4 × 10⁵ particles/μL (3σ). This assay possesses high specificity to distinguish exosomes derived from different cell lines, and has successfully been validated in patient and healthy plasma samples. Furthermore, the probe can effectively detect the exosomes in 30% fetal bovine serum, indicating that the biological matrix has a negligible effect on this method. This developed label-free, convenient and highly sensitive biosensor will offer a great opportunity for exosomes quantification in biological study and clinical application.

A turn-on fluorescence probe Eu3+ functionalized Ga-MOF integrated with logic gate operation for detecting ppm-level ciprofloxacin (CIP) in urine

The threatening of antibiotic drugs for human and environment is being paid more and more attention. Ciprofloxacin (CIP), a strong quinolone antibiotic drug widely used in therapeutic treatments, is the most frequently detected in surface waters among the fluoroquinolones, which represents animal and human health risks. A novel highly fluorescent Ga-based hybrid (Eu³⁺@1) has been synthesized based on metal-organic framework (MOF) by encapsulating lanthanide cations Eu³⁺ in its channels. The as-synthesized compound possesses excellent water and pH-independent stability. It displays week red luminescence of Eu³⁺ in itself and can sense the CIP concentration as turn-on fluorescent probe in the human urine. With addition of CIP, the evident luminescence enhancement is clearly observed from the Eu³⁺@1. Linear correlation between the fluorescence intensity and the concentration of CIP is investigated, proving the excellent performance of Eu³⁺@1 in the detection of CIP with linear range (0.01-0.2 mg/mL) and low detection limit (2.4 ppm or 2.4 μg/mL). The response time is also very quick, less than 3 min. Based on these findings, we introduce AND logic gate strategy to the probe. The input of the logic gates (0, 1), (0, 1, 1), (1, 1, 1) cause the different outputs of CIP determination "LOW" (<25 ppm),"NORMAL" (25-76 ppm), "HIGH" (>76 ppm), respectively. The novel strategy can be applied for a real-time CIP concentration evaluation by intelligent discrimination.