Micro solid phase extraction of cadmium and lead on a new ion-imprinted hierarchical mesoporous polymer via dual-template method in river water and fish muscles: Optimization by experimental design

High speed enrichment of benzoylurea insecticides by hierarchical pore nitrogen doped carbon materials induced with hydrogen-bonded organic frameworks

The high speed enrichment of benzoylurea insecticides (BUs) in complex matrices is an essential and challenging step. The present study focuses on the synthesis of a hierarchical pore nitrogen-doped carbon material for magnetic solid phase extraction (MSPE) of BUs. This material was prepared through the carbonization of a composite material ZIF-67@MCA which assembly with hydrogen-bonded organic frameworks (melamine-cyanurate, MCA) and zeolitic imidazolate framework (ZIF-67) at room temperature. The optimal adsorption effect is achieved when the mass ratio of ZIF-67 to MCA is 1/3, and the carbonization was performed at 600 °C, the such obtained carbon material was denoted as 1/3ZIF-67@MCA-DCs-600. The material was characterized with various physical methods including X-ray diffractometry (XRD), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), vibrating sample magnetometer (VSM), water contact angle measurement, Raman spectrometry. 1/3ZIF-67@MCA-DCs-600 exhibits a macro-mesoporous 3D structure with a high degree of nitrogen doping and relatively large specific surface area, making it suitable for magnetic solid phase extraction (MSPE). The adsorption of BUs with concentration of 100 ng mL-1 can reach equilibrium within 5 s. The interaction between BUs and the adsorbent, facilitated by π-π stacking, hydrophobic interactions, hydrogen bonding forces, as well as the material's porosity, enables efficient extraction recoveries ranging from 45 % to 92 %. The enrichment of BUs was achieved through the establishment of an MSPE method under optimized conditions, which was further coupled with high performance liquid chromatography (HPLC) for the determination of the four BUs. The linear range spans from 5 ng ml-1 to 1000 ng ml-1 with the correlation coefficient (R2) of ≥ 0.99, Meanwhile, the detection limit for these four BUs falls within the range of 0.01 to 0.10 ng ml-1. The material exhibits good reusability and can be reused for at least 5 cycles. Inter day and intra-day precision ranges from 2.1-7.9 % and 1.0-5.4 %, respectively. The method demonstrates a high level of reliability in practical applications for the determination of BUs.

Unveiling the revolutionary role of nanoparticles in the oil and gas field: Unleashing new avenues for enhanced efficiency and productivity

Prominent oil corporations are currently engaged in a thorough examination of the potential implementation of nanoparticles within the oil and gas sector. This is evidenced by the substantial financial investments made towards research and development, which serves as a testament to the significant consideration given to nanoparticles. Indeed, nanoparticles has garnered increasing attention and innovative applications across various industries, including but not limited to food, biomedicine, electronics, and materials. In recent years, the oil and gas industry has conducted extensive research on the utilization of nanoparticles for diverse purposes, such as well stimulation, cementing, wettability, drilling fluids, and enhanced oil recovery. To explore the manifold uses of nanoparticles in the oil and gas sector, a comprehensive literature review was conducted. Reviewing several published study data leads to the conclusion that nanoparticles can effectively increase oil recovery by 10 %-15 % of the initial oil in place while tertiary oil recovery gives 20-30 % extra initial oil in place. Besides, it has been noted that the properties of the reservoir rock influence the choice of the right nanoparticle for oil recovery. The present work examines the utilization of nanoparticles in the oil and gas sector, providing a comprehensive analysis of their applications, advantages, and challenges. The article explores various applications of nanoparticles in the industry, including enhanced oil recovery, drilling fluids, wellbore strengthening, and reservoir characterization. By delving into these applications, the article offers a thorough understanding of how nanoparticles are employed in different processes within the sector. This analysis may prove highly advantageous for future studies and applications in the oil and gas sector.

Application Prospect of Ion-Imprinted Polymers in Harmless Treatment of Heavy Metal Wastewater

With the rapid development of industry, the discharge of heavy metal-containing wastewater poses a significant threat to aquatic and terrestrial environments as well as human health. This paper provides a brief introduction to the basic principles of ion-imprinted polymer preparation and focuses on the interaction between template ions and functional monomers. We summarized the current research status on typical heavy metal ions, such as Cu(II), Ni(II), Cd(II), Hg(II), Pb(II), and Cr(VI), as well as metalloid metal ions of the As and Sb classes. Furthermore, it discusses recent advances in multi-ion-imprinted polymers. Finally, the paper addresses the challenges faced by ion-imprinted technology and explores its prospects for application.

Simultaneous preconcentration and quantification of ultra-trace tin and lead species in seawater by online SPE coupled with HPLC-ICP-MS

BACKGROUND

Tin and lead contamination is a global threat to marine ecosystems considering their species-specific toxicity, bioavailability and mobility. Hence simultaneous measurement of multiple tin and lead compounds at μg L-1 to pg L-1 levels in environmental water is always an indispensable but challengeable task. High performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) is one of the most widely used choices for this purpose because of good sensitivity, strong separation power and good compatibility. Previous HPLC-ICP-MS methods based on a single elemental speciation strategy are low-efficiency and sensitivity-insufficient for a large set of unstable samples and interaction of multiple metal(loid)s down to ng L-1 levels.

RESULTS

In this study, we developed a sensitive, efficient and environment-friendly analytical method for accurate quantification of inorganic and organic species of tin and lead simultaneously based on HPLC-ICP-MS with online integration of solid phase extraction (SPE). By using graphene oxide modified silica conditioned with 1 mM benzoic acid to enrich tin and lead species from 10 mL sample, detection limits were improved to 2-8 pg per liter due to satisfactory enrichment factors (522-2848 folds). The SPE-HPLC-ICP-MS method was applicable to quantification of ultra-trace tin and lead species at pg L-1 levels in uncontaminated seawater. Tributyltin was the only tin species detected at subnanograms per liter levels while Pb(II) was the only lead species detected at several nanograms per liter in thirteen coastal seawater samples collected in Hangzhou Bay, indicating light contamination of tin and lead.

SIGNIFICANCE

Overall, the proposed SPE-HPLC-ICP-MS method is highly sensitive, efficient and environment-friendly that are fairly suitable to routine speciation analysis of tin and lead in environmental, food, and biological samples.

Green synthesis and investigation of antioxidant and antibacterial activity of new derivatives of chromenoazepines employing CuO/TiO2@MWCNTs

The synthesis of novel, high-yield derivatives of chromenoazepine was investigated in this work. CuO/TiO2@MWCNTs was used as a nanocatalyst in a multicomponent reaction involving 4-aminocumarine, activated acetylenic chemicals, and alkyl bromide in room temperature water to create these novel compounds. Using MCRs of 4-aminocumarine, isothiocyanate, and alkyl bromide in the presence of CuO/TiO2@MWCNTs as nanocatalysts in room-temperature water, chromenothiazepines were synthesized under comparable conditions. The freshly synthesized azepine exhibits antioxidant activity since its NH group has undergone two evaluation processes. Additionally, using two types of Gram-negative bacteria in a disk distribution procedure, the antibacterial activity of recently developed azepines was evaluated, and these compounds also inhibited the growth of Gram-positive bacteria. This method's benefits include quick reaction times, large product yields, and straightforward catalyst and product separation through easy steps.

Construction of 1, 10-phenanthroline functionalized magnetic starch as a lead (II) tagged surface imprinted biopolymer for highly selective targeting of toxic lead ions

In this research 1, 10 - phenanthroline functionalized CaFe₂O₄ - starch was employed as a magnetic ion-imprinted polymer (IIP) for highly selective targeting toxic Pb²⁺ ions from aqueous media. VSM analysis revealed that the sorbent has magnetic saturation of 10 emu g^-1 which is appropriate for magnetic separation. Moreover, TEM analysis confirmed that the adsorbent is composed of particles with a mean diameter of 10 nm. According to XPS analysis, lead coordination with phenanthroline is the main adsorption mechanism that is along with electrostatic interaction. A maximum adsorption capacity of 120 mg g^-1 was obtained within 10 min at a pH of 6 and an adsorbent dosage of 20 mg. Kinetic and isotherm studies showed that lead adsorption followed the pseudo-second-order and Freundlich models, respectively. The selectivity coefficient of Pb (II) relative to Cu(II), Co(II), Ni(II), Zn(II), Mn(II), and Cd(II) was 4.7, 14, 20, 36, 13 and 25, respectively. Moreover, the IIP represents the imprinting factor of 1.32. The sorbent showed good regeneration after five cycles of the sorption/desorption process with an efficiency of >93 %. Finally represented IIP was used for lead preconcentration from various matrices i.e., water, vegetable, and fish samples.

Urea-based magnetic porous organic frameworks as novel adsorbent for the enrichment of phenylurea herbicides in foods

A novel urea-based magnetic porous organic frameworks Fe₃O₄@UPOFs (ETTA-PPDI) was synthesized by a simple polymerization reaction under mild conditions. The adsorbent displayed desirable adsorption performance for phenylurea herbicides (PUHs) with optimized adsorption time of only 4 min. The adsorption capacities of the adsorbent for PUHs ranged from 47.30 to 111.93 mg g^-1. A magnetic solid-phase extraction based on Fe₃O₄@UPOFs combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established for the efficient determination of six PUHs in food samples (wheat, edible oil and cucumber), with determination coefficient (R²) ≥ 0.9972. The LODs of the method were in the range of 0.003-0.07 μg kg^-1 and recoveries ranged from 82.00 to 112.53%. The relative standard deviations were lower than 6.7%. The newly prepared adsorbent displayed great application prospects for the efficient enrichment of trace phenylurea herbicides in complex food matrices.

Electrospun composite nanofibers modified with silver nanoparticles for extraction of trace heavy metals from water and rice samples: An highly efficient and reproducible sorbent

Herein, a composite of polyacrylonitrile (PAN)/agar/silver nanoparticles (AgNPs) electrospun nanofibers was fabricated and applied as an efficient sorbent for thin-film micro-extraction (TFME) of five metal ions followed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Incorporating agar into the nanofibers followed by in situ photo-reductive reaction under UV-lamp resulted in highly uniform dispersion of AgNPs in the nanofibers. Under the optimized conditions, agreeable linearity was acquired in the range of 0.5-250.0 ng mL^-1 (R² ≥ 0.9985). The LODs (based on S/N = 3) were attained in the range of 0.2 to 0.5 ng mL^-1. The relative standard deviations (RSDs) were between 4.5% and 5.6% (intra-day, n = 5) and 5.3%-5.9% (inter-day, n = 3) for three sequential days. The developed method was investigated with water and rice samples, and recoveries (93.9-98.0%) indicated that the PAN/agar/AgNPs could be a promising film for the adsorption of heavy metal ions in varied samples.

A rapid magnetic-based purification of Cd2+ and Pb2+ prior to portable electrochemical determination for grain

How to quickly separate and detect cadmium (Cd²⁺) and lead (Pb²⁺) from solid samples is a difficult problem that needs to be solved. For this, Fe₃O₄@agarose@iminodiacetic acid (IDA) was synthesized and used for rapid purification of Cd²⁺ and Pb²⁺. This material can remove complex matrix interference completely within a short time of 15 min. The mechanism of the adsorption kinetics fit well to a pseudo-second-order model. A portable screen-printed electrodes (SPEs)-based electrochemical detection platform was established. After coupling with the pretreatment, the whole detection process only took within 30 min. The limits of detection (LOD) were ten times lower than those of the Codex general standard, with values of 0.02 and 0.01 mg/kg for Pb²⁺ and Cd²⁺, respectively. The recoveries ranged from 84.1% to 109.7% in naturally contaminated grain, in good agreement with the ICP-MS, demonstrating great prospects for the rapid screening and monitoring of Cd²⁺ and Pb²⁺ in grain.

Recent Development on Determination of Low-Level 90Sr in Environmental and Biological Samples: A Review

In the context of the rapid development of the world's nuclear power industry, it is vital to establish reliable and efficient radioanalytical methods to support sound environment and food radioactivity monitoring programs and a cost-effective waste management strategy. As one of the most import fission products generated during human nuclear activities, ⁹⁰Sr has been widely determined based on different analytical techniques for routine radioactivity monitoring, emergency preparedness and radioactive waste management. Herein, we summarize and critically review analytical methods developed over the last few decades for the determination of ⁹⁰Sr in environmental and biological samples. Approaches applied in different steps of the analysis including sample preparation, chemical separation and detection are systematically discussed. The recent development of modern materials for ⁹⁰Sr concentration and advanced instruments for rapid ⁹⁰Sr measurement are also addressed.

Design strategies, surface functionalization, and environmental remediation potentialities of polymer-functionalized nanocomposites

Inorganic nanoparticles (NPs) have a tunable shape, size, surface morphology, and unique physical properties like catalytic, magnetic, electronic, and optical capabilities. Unlike inorganic nanomaterials, organic polymers exhibit excellent stability, biocompatibility, and processability with a tailored response to external stimuli, including pH, heat, light, and degradation properties. Nano-sized assemblies derived from inorganic and polymeric NPs are combined in a functionalized composite form to import high strength and synergistically promising features not reflected in their part as a single constituent. These new properties of polymer/inorganic functionalized materials have led to emerging applications in a variety of fields, such as environmental remediation, drug delivery, and imaging. This review spotlights recent advances in the design and construction of polymer/inorganic functionalized materials with improved attributes compared to single inorganic and polymeric materials for environmental sustainability. Following an introduction, a comprehensive review of the design and potential applications of polymer/inorganic materials for removing organic pollutants and heavy metals from wastewater is presented. We have offered valuable suggestions for piloting, and scaling-up polymer functionalized nanomaterials using simple concepts. This review is wrapped up with a discussion of perspectives on future research in the field.

Influence of Synthesis Parameters and Polymerization Methods on the Selective and Adsorptive Performance of Bio-Inspired Ion Imprinted Polymers

Ion-imprinted polymers (IIPs) have been widely used in different fields of Analytical Sciences due to their intrinsic selective properties. However, the success of chemical imprinting in terms of selectivity, as well as the stability, specific surface area, and absence of swelling effect depends on fully understanding the preparation process. Therefore, the proposal of this review is to describe the influence of relevant parameters on the production processes of ion-imprinted polymers, including the nature (organic, inorganic, or hybrid materials), structure, properties of the salt (source of the metal ion), ligand, crosslinking agent, porogenic solvent, and initiator. Additionally, different polymerization methods are discussed, the classification of IIPs as well as the applications of these adsorbent materials in the last years (2017–2022).

Tailored-designed material for the preconcentration of Cd(II) on glycidyl methacrylate-based ion-imprinted polymer for flame atomic absorption for trace determination in real samples: multivariate optimization

A new Cd(II)-imprinting polymer was synthesised based on glycidyl methacrylate (Fe₃O₄@GMA@IIP) and employed to develop a dispersive magnetic solid-phase extraction method for the preconcentration prior to the determination of Cd(II) from the environmental samples. A central composite design (CCD) based on response surface methodology was used for optimization of the process variables and the material shows the promising saturation adsorption capacity of 28.21 mg g^-1 under the optimum pH of 4.9 within 15.2 min at saturation concentration 914 μg mL^-1. The experimental data were well described by Sips isotherm model and Brouers-Sotolongo fractal kinetic model that indicated the surface heterogeneity and involvement of both chemisorption and physisorption process. Thermodynamic results documented the endothermic and spontaneous nature of adsorption. The sorbent manifest the economic feasibility maintaining its sorption efficiency after the regeneration by 1 M HNO₃ and reusability up to 6 adsorption/desorption cycles. The developed method exhibited the preconcentration factor of 30 and a high degree of tolerance for matrix ions. Limit of detection (LOD) and quantification (LOQ) were calculated as 3.054 and 10.182 μg L^-1 respectively. The developed method was validated by the standard reference material and spiking addition method in real samples, and obtained results showed good agreement in accordance with spiking values. The ease of magnetic separation, high selectivity, good adsorption capacity and faster kinetics made this material a promising candidate for Cd(II) determination in various food and aqueous samples.

Determination, Separation and Application of 137Cs: A Review

In the context of the rapid development of the world's nuclear power industry, it is necessary to establish background data on radionuclides of different samples from different regions, and the premise of obtaining such basic data is to have a series of good sample processing and detection methods. The radiochemical analysis methods of low-level radionuclides ¹³⁷Cs (Cesium) in environmental and biological samples are introduced and reviewed in detail. The latest research progress is reviewed from the five aspects of sample pretreatment, determination, separation, calculation, application of radioactive cesium and the future is proposed.

Development of copper nanoflowers based dispersive solid-phase extraction method for cadmium determination in shalgam juice samples using slotted quartz tube atomic absorption spectrometry

In this work, dispersive solid-phase extraction procedure was developed for trace cadmium determination before flame atomic absorption spectrometry (FAAS) measurement. Copper(II) based nanoflowers were synthesized to utilize as adsorbent for preconcentration of cadmium. The detection power of the spectrometric system was enhanced by placing a slotted quartz tube (SQT) onto the flame burner which increases the residence time of the analyte atoms in the flame region. The analytical performance of the developed system was evaluated with and without SQT equipment and the enhancement in detection power was calculated by the ratio of detection limits of CuNF-DSPE-FAAS (copper nanoflower based dispersive solid phase extraction-flame atomic absorption spectrometry) and FAAS system. Enhancement was determined as 73 and 104.3 times for CuNF-DSPE-FAAS and CuNF-DSPE-SQT-FAAS (CuNF-DSPE-slotted quartz tube-FAAS), respectively. Percent recovery results indicated the applicability of the developed method for the determination of trace cadmium.

Functionalization and Modification of Polyethylene Terephthalate Polymer by AgCl Nanoparticles under Ultrasound Irradiation as Bactericidal

Polyethylene terephthalate polymer (PET) is widely used in diverse areas. In the current study, the surface of PET is modified in two steps in order to improve the quality. At first, the polymer was functionalized with carboxylic groups, and Fourier transform infrared spectroscopy studies were used to verify functionalization. Then, AgCl nanoparticles were synthesized on COOH functional groups on the surface of PET using a sonochemistry method by sequential dipping of the functionalized polymer in an alternating bath of potassium chloride and silver nitrate under ultrasonic irradiation. The effects of ultrasonic irradiation power, the number of dipping steps, and pH on the growth of AgCl nanoparticles as effective parameters on size and density of synthesized Ag nanoparticles were studied. The results of scanning electron microscopy studies showed that the size and density of AgCl nanoparticles under ultrasonic irradiation with a power of 100 W are better than those of AgCl nanoparticles under irradiation with a power of 30 W. Also, by 15 times dipping the polymer into the reagent solutions in pH = 9, the modified polymer with a greater number of nanoparticles with suitable size can be reached. Antibacterial properties of PET containing AgCl nanoparticles were investigated against six Gram-positive and Gram-negative bacteria species, and the results showed significant antibacterial activity, while functionalized PET did not have a significant effect on both types of bacteria.

Synthesis of a magnetic SBA-15-NH2@Dual-Template Imprinted Polymer for solid phase extraction and determination of Pb and Cd in vegetables; Box Behnken design

In this study, a simple one-step method was applied for extraction and determination of lead and cadmium. The significant variables in extraction and pre-concentration were identified using analysis of variance and their behavior was modeled. Dual-template imprinted polymer was synthesized on modified Mesoporous silica structures coated with Fe₃O₄ magnetic nanoparticles. The optimum condition was 6.12 for pH, 40.62 mg for the polymer amount and 17.38 for the ultrasonic time. Concentration range, correlation coefficient, limit of detection and relative standard deviation for lead were reported to be 0.5-950, 0.9988, 0.35 μg L^-1 and 3.5%, respectively. For cadmium the above mentioned figure of merits were 0.3-980, 0.9969, 0.15 μg L^-1 and 2.4%, respectively. The adsorption capacities for lead and cadmium were reported to be 10.28 and 10.38, while their imprinting factors were 5.89 and 6.36, respectively.

Cassava Starch-Based Thermo-Responsive Pb(II)-Imprinted Material: Preparation and Adsorption Performance on Pb(II)

Heavy metal pollution is currently an increasing threat to the ecological environment, and the development of novel absorbents with remarkable adsorption performance and cost-effectiveness are highly desired. In this study, a cassava starch-based Pb(II)-imprinted thermo-responsive hydrogel (CPIT) had been prepared by using cassava starch as the bio-substrate, N-isopropyl acrylamide (NIPAM) as the thermo-responsive monomer, and Pb(II) as the template ions. Later, a variety of modern techniques including FTIR, DSC, SEM, and TGA were employed to comprehensively analyze the characteristic functional groups, thermo-responsibility, morphology, and thermal stability of CPIT. The obtained material exhibited superior performance in adsorption of Pb(II) and its maximum adsorption capacity was high-up to 114.6 mg/g under optimized conditions. Notably, the subsequent desorption (regeneration) process was fairly convenient by simply rinsing with cold deionized water and the highest desorption efficiency could be achieved as 93.8%. More importantly, the adsorption capacity of regenerated CPIT still maintained 88.2% of the value of starting material even after 10 recyclings. In addition, the excellence of CPIT in selective adsorption of Pb(II) should also be highlighted as its superior adsorption ability (97.9 mg/g) over the other seven interfering metal ions.

A silanized magnetic amino-functionalized carbon nanotube-based multi-ion imprinted polymer for the selective aqueous decontamination of heavy metal ions

A novel adsorbent comprising a silanized magnetic amino-functionalized carbon nanotube-based multi-ion imprinted polymer is introduced as an ideal candidate for the simultaneous and selective adsorptive remediation of heavy metal ions from contaminated water.

Adsorption removal of ibuprofen and naproxen from aqueous solution with Cu-doped Mil-101(Fe)

Due to the excellent anti-inflammatory effect, ibuprofen and naproxen have been widely used in the people's daily life, which inevitably leads to their pollution in natural water environment. The removal of these chemicals from water has drawn great interests. Here, a new Cu-doped Mil-101(Fe) was synthesized through a one-step solvothermal method and successfully applied for the adsorption removal of ibuprofen and naproxen from water. A series of characterization techniques (FESEM, TEM, N₂ adsorption-desorption analysis, XRD and FT-IR) were applied to explore the physicochemical properties of the prepared Cu-doped Mil-101(Fe). The adsorption performances of the Cu-doped Mil-101(Fe) for ibuprofen and naproxen, including the adsorption kinetics and isotherms, and effects of diverse influencing factors (pH, ionic strength, and natural organic matter) were examined through batch experiments. The adsorption kinetics and isotherms of ibuprofen and naproxen on the Cu-doped Mil-101(Fe) fitted well with the pseudo-second-order model and Langmuir model, respectively. The maximum adsorption capacities of Cu-doped Mil-101(Fe) were 497.3 and 396.5 mg/g for ibuprofen and naproxen, respectively. The pH of solution in a range of 3-9 exerted no significant effects on the adsorption process. The adsorption was almost unaffected by the ionic strength and humic acid. The π-π interaction and hydrogen bond interaction between the adsorbent and adsorbates were found to be accountable for adsorption. The Cu-doped Mil-101(Fe) was readily regenerated by ethanol and could be repeatedly used.

The selective recognition mechanism of a novel highly hydrophobic ion-imprinted polymer towards Cd(ii) and its application in edible vegetable oil

Edible vegetable oils are easily contaminated by heavy metals, resulting in the oxidative degradation of oils and various health effects on humans. Therefore, it is very important to develop a rapid and efficient method to extract trace heavy metals from vegetable oils. In this work, a highly hydrophobic ion-imprinted polymer (IIP) was synthesized on a novel raspberry (RS)-like particle surface. The synthesized IIP@RS was characterized and used in solid-phase extraction (SPE) for the selective and fast adsorption of Cd(ii) from vegetable oils. The results showed that IIP was successfully coated onto RS particles with a high specific surface area (458.7 m² g⁻¹) and uniform porous structure. The contact angle (θ) value (141.8°) of IIP@RS was close to the critical value of super-hydrophobic materials, which is beneficial to their adsorption in hydrophobic vegetable oils. The IIP@RS also exhibited excellent adsorption ability and selectivity to Cd(ii) with a maximum adsorption capacity of 36.62 mg g⁻¹, imprinting factor of 4.31 and equilibrium adsorption rate of 30 min. According to isothermal titration calorimetry results, the recognition behavior of IIP@RS for Cd(ii) was mainly contributed by Cd(ii)-induced cavities during gel formation and coordination between Cd(ii) and –SH groups in imprinted cavities. Furthermore, the adsorption process driven by entropy and enthalpy was spontaneous at all temperatures. In real vegetable oil samples, IIP@RS-SPE adsorbed approximately 96.5–115.8% of Cd(ii) with a detection limit of 0.62 μg L⁻¹. Therefore, IIP@RS has wide application prospects in enriching and detecting Cd(ii) from vegetable oil.

Edible vegetable oils are easily contaminated by heavy metals, resulting in the oxidative degradation of oils and various health effects on humans.

Multi-ion imprinted polymers (MIIPs) for simultaneous extraction and preconcentration of Sb(III), Te(IV), Pb(II) and Cd(II) ions from drinking water sources

Simultaneous extraction and preconcentration of several potentially toxic metal ions have received great attention because of their toxicological effects on aquatic life and human beings. Multi-ion imprinted polymers (MIIP) have proved to be promising adsorbents with excellent specific recognition performance than single-ion imprinted polymer. Therefore, in this study, the MIIP strategy was employed for simultaneous extraction and enrichment of Sb(III), Cd(II), Pb(II) and Te(IV) ions from drinking water sources. MIIPs was used as a sorbent material in ultrasound-assisted dispersive solid phase extraction combined with inductively coupled plasma optical emission spectrometry (UA-DSPE/ICP-OES). The experimental parameters that affect the extraction efficiency and recovery of Sb(III), Cd(II), Pb(II) and Te(IV) were investigated using response surface methodology. Under optimum conditions, the enhancement factors, linear range, limit of detection (LOD) and limit of quantification (LOQ) were 37.7-51.1, 0.04-100 µg L^-1, 0.011-0.28 µg L^-1, 0.037-093 µg L^-1, respectively. The intra-day (n = 10) and inter-day (n = 5) precision expressed as relative standard deviations (%RSDs,) were 3% and 5%, respectively. The proposed UA-DSPE/ICP-OES method was applied for preconcentration and determination of the trace metal ions in environmental samples. Furthermore, the accuracy of the method was evaluated using spiked recovery experiments and the percentage recoveries ranged from 95% to 99.3%.

Vortex-assisted magnetic solid-phase extraction of cadmium in food, medicinal herb, and water samples using silica-coated thiol-functionalized magnetic multiwalled carbon nanotubes as adsorbent

The current work focuses on the facile and effective synthesis of a new nanocomposite based on multiwalled carbon nanotubes (MWCNT) decorated with magnetic core-shell Fe₃O₄@SiO₂ and functionalized with 3-mercaptopropyltrimethoxysilane (3-MPTS) used in the vortex-assisted dispersive magnetic solid-phase extraction (VA-DMSPE) of Cd(II) ions in environmental and food samples. The nanocomposite was characterized and the parameters that influenced the VA-DMSPE were optimized through a fractional factorial design 2^5-1. The proposed method provided a preconcentration factor of 33.14 times, detection and quantification limits of 0.090 μg L^-1 and 0.302 μg L^-1, respectively, and a linearity range of 0.001-40.0 μg L^-1. The developed method was effectively applied to preconcentrate and determine Cd(II) in water, tobacco, green tea leaves, ginkgo biloba, carrots, and rice samples, and its accuracy was evaluated using GF AAS.

Green Aspects in Molecularly Imprinted Polymers by Biomass Waste Utilization

Molecular Imprinting Polymer (MIP) technology is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. In the last decades, MIP technology has gained much attention from the scientific world as summarized in several reviews with this topic. Furthermore, green synthesis in chemistry is nowadays one of the essential aspects to be taken into consideration in the development of novel products. In accordance with this feature, the MIP community more recently devoted considerable research and development efforts on eco-friendly processes. Among other materials, biomass waste, which is a big environmental problem because most of it is discarded, can represent a potential sustainable alternative source in green synthesis, which can be addressed to the production of high-value carbon-based materials with different applications. This review aims to focus and explore in detail the recent progress in the use of biomass waste for imprinted polymers preparation. Specifically, different types of biomass waste in MIP preparation will be exploited: chitosan, cellulose, activated carbon, carbon dots, cyclodextrins, and waste extracts, describing the approaches used in the synthesis of MIPs combined with biomass waste derivatives.

In-site and solvent-free exfoliation of porous graphene oxide from pencil lead fiber for solid-phase microextraction of cadmium ion before GF-AAS determination

Graphene oxide (GO)-functionalized pencil lead fiber was prepared for the first time by in situ oxidation and exfoliation of graphite contained in pencil lead fiber to porous graphene oxide structure via a one-step solvent-free dielectric barrier discharge (DBD) microplasma treatment. This new fiber was demonstrated as a highly efficient and low-cost solid-phase microextraction (SPME) fiber for the determination of toxic metal ions. The fiber extraction performance was evaluated by using cadmium as a model analyte in a direct immersing SPME mode. Unlike most commercially available and other lab-built fibers, the preparation of the graphene oxidized pencil lead fiber is environmentally friendly, low cost, and non-toxic without using any organic solvents. The fiber is robust due to its coating-free configuration. Furthermore, high extraction efficiency and high sensitivity for cadmium can be obtained due to the abundant oxygen-containing functional groups on the surface of the novel fiber. After extraction, the cadmium adsorbed on the fiber was desorbed to 150-μL solution. Graphite furnace atomic absorption spectrometry (GF-AAS) with low sample consumption was used to determine cadmium. The calibration curve for cadmium ions was linear in a range 0.04-0.26 μg L^-1 with a detection limit of 0.005 μg L^-1. A relative standard deviation (RSD, n = 5) of 2.1% was obtained at 0.1 μg L^-1 of cadmium. The sensitivity enhancement factor (EF) value of the proposed SPME method was 25. The SPME fiber was successfully applied to determine cadmium in tap water, river water, and pond water with spike recoveries ranging from 94 to 105%. Pipe network water samples were also analyzed to evaluate the cadmium release to drinking water due to the corrosion of tubes.