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Facile and ultrasensitive detection of Pb2+ in water for remote or resource-limited environments remains challenging. DNAzyme-based colorimetric nanobiosensors have been extensively studied to regulate the assembly of functionalized gold nanoparticles (AuNPs). However, these nanobiosensors have been criticized for their low sensitivity owing to the difficulty of dissociating DNAzyme embedded in AuNP aggregates. To address this issue, we rationally designed a DNAzyme by introducing an adenine-cytosine (A-C) mismatch to strengthen the disassembly of DNAzyme-linked nanostructures. As proof of concept, a "turn on" colorimetric nanobiosensor integrated with mismatched DNAzyme and functionalized AuNPs was first developed for Pb2+ detection. Under the optimal detection conditions, the obtained typical calibration curve shows a detection limit of 8.6 nmol/L, with an approximately 11-fold sensitivity improvement in Pb2+ detection compared with unmismatched DNAzyme, and a linear response range from 10 to 300 nmol/L. This nanobiosensor demonstrated robust selectivity and satisfactory recovery rates between 86.5% and 106.4% for Pb2+ in spiked environmental water samples. Additionally, the detection process is user-friendly and can be completed within 30 min, requiring only a simple water sample addition step. Considering the extensive applications of DNAzyme in conjunction with nanoparticles, this study provides a valuable reference for designing other DNAzyme-powered nanoparticle assemblies in biosensing systems. [ABSTRACT FROM AUTHOR]

In recent years, nanozymes have attracted particular interest and attention as catalysts because of their high catalytic efficiency and stability compared with natural enzymes, whereas how to use simple methods to further improve the catalytic activity of nanozymes is still challenging. In this work, we report a trimetallic metal–organic framework (MOF) based on Fe, Co and Ni, which was prepared by replacing partial original Fe nodes of the Fe-MOF with Co and Ni nodes. The obtained FeCoNi-MOF shows both oxidase-like activity and peroxidase-like activity. FeCoNi-MOF can not only oxidize the chromogenic substrate 3,3,5,5-tetramethylbenzidine (TMB) to its blue oxidation product oxTMB directly, but also catalyze the activation of H2O2 to oxidize the TMB. Compared with corresponding monometallic/bimetallic MOFs, the FeCoNi-MOF with equimolar metals hereby prepared exhibited higher peroxidase-like activity, faster colorimetric reaction speed (1.26–2.57 folds), shorter reaction time (20 min) and stronger affinity with TMB (2.50–5.89 folds) and H2O2 (1.73–3.94 folds), owing to the splendid synergistic electron transfer effect between Fe, Co and Ni. Considering its outstanding advantages, a promising FeCoNi-MOF-based sensing platform has been designated for the colorimetric detection of the biomarker H2O2 and environmental pollutant TP, and lower limits of detection (LODs) (1.75 μM for H2O2 and 0.045 μM for TP) and wider linear ranges (6–800 μM for H2O2 and 0.5–80 μM for TP) were obtained. In addition, the newly constructed colorimetric platform for TP has been applied successfully for the determination of TP in real water samples with average recoveries ranging from 94.6% to 112.1%. Finally, the colorimetric sensing platform based on FeCoNi-MOF is converted to a cost-effective paper strip sensor, which renders the detection of TP more rapid and convenient. [ABSTRACT FROM AUTHOR]

To prepare a magnetic nano-adsorbent for efficient and fast removal of a dye, especially if present in trace concentration, along with a facile green synthetic methodology is a great challenge. The present work realises this task by combining the well-known advantages of both solvent-free microwave approach, nanoscale particle size and the fast magnetic separation. Thus, silica-coated magnetite nanoparticles (Fe3O4 NPs@SiO2) as an important precursor were produced directly via an optimised solid-solid interaction between silica and Fe3O4 NPs at 200 watt of microwave irradiation for only 10 min. The as-developed adsorbent was characterised using Fourier Transform Infrared (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) analysis. Its performance with no further modification for removal of Methylene blue (MB) dye from aqueous solution was achieved in a batch mode as a function of pH, contact time, adsorbent dose and initial dye concentration. The results demonstrate excellent removal efficiency (98.9%) within 5 min, as compared with recent adsorbents synthesised through a multi-steps reaction. Modelling of the experimental data denoting well-fitting with both Langmuir sorption isotherm (monolayer capacity 47.98 mg/g) and pseudo-second-order kinetic model. A possible MB binding mechanism has been proposed taking in account values of dissociation constants of the different forms of silica surface silanol groups. The adsorbent after first was successfully regenerated in situe for five consecutive cycles. Moreover, it was proved to be valid for collecting efficiently trace concentrations of MB spiked environmental water samples to be in the range 92.4–98.8%. [ABSTRACT FROM AUTHOR]

Diclofenac sodium (DS) is now recognized as an emerging pollutant, and is one of the most commonly discovered pharmaceuticals in water due to its extensive application in the clinic. This study examined the adsorption performance of a polystyrene-supported ionic liquid material (PS-[Nim][Cl]) for the removal of diclofenac sodium (DS) from water. The data from this study showed that maximum removal of DS can be achieved even in conditions with significant pH and temperature fluctuations. The adsorption process was rapid, more than 90% of DS could be removed within the first 10 min and adsorption equilibrium could be reached in just 30 min with a high removal efficiency (>99.9%). Adsorption reached saturation with a maximum adsorption capacity of approximately 785.2 mg/g. Moreover, the presence of K+, Na+, Ca2+, Mg2+, Cl-, and H2PO4- ions had little influence on DS adsorption, even when concentrations of these ions were 10,000 times higher than that of DS in water samples. The adsorbent also showed promising performance for the treatment of environmental water samples and groundwater containing DS. [ABSTRACT FROM AUTHOR]

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The current research is an attempt to analyze on-site selenium(IV) ions in environmental water samples using an eco-friendly miniaturized sensor developed by deposition of a very thin amount of metallic bismuth in a solid Bi electrode tightly closed in miniaturized housing. Numerous experimental variables are optimized, including the composition of the supporting electrolyte and its pH, as well as activation and accumulation conditions. Under optimized measurement conditions, the method shows high sensitivity, permitting a very low limit of detection equal to 7 × 10−10 mol L−1 to be achieved in a short accumulation time of 50 s. The performance of this microsensor was investigated against numerous interference factors and its good anti-interference capability was demonstrated. A series of voltammetric experiments by differential pulse cathodic stripping voltammetry (DPCSV) were carried out and they proved that the miniaturized sensor is characterized by very good accuracy and precision as well as long-term stability. The solid bismuth microelectrode displays a good voltammetric response in the analysis of diverse samples with a complex matrix and demonstrates a good recovery rate. [ABSTRACT FROM AUTHOR]

This work presents a proposal for an adsorptive stripping voltammetric (AdSV) method for gallium(III) determination at an eco-friendly multiwall carbon nanotube/spherical glassy carbon (MWCNT/SGC) electrode modified with a lead film. The operational factors influencing the sensitivity of the AdSV procedure were thoroughly investigated, and their most favorable values were chosen (0.1 mol L−1 acetate buffer solution pH = 5.6; 7 × 10−5 mol L−1 Pb(II); 2 × 10−4 mol L−1 cupferron; potential/time of lead film formation: −1.9 V/30 s; potential/time of Ga(III)–cupferron adsorption: −0.75 V/30 s). The newly developed MWCNT/SGCE has proven to be a competitive substrate to the glassy carbon electrode to create a lead film electrode, since it allows the determination of gallium in a wider range of concentrations from 3 × 10−9 to 4 × 10−7 mol L−1 with a lower limit of detection equal to 9.5 × 10−10 mol L−1. The elaborated procedure has been shown to be highly selective and insensitive to the presence of an even 100-fold excess of most of the ions commonly found in environmental waters. The MWCNT/SGC sensor, which can maintain >95% of its original response after 70 days of use, has been successfully applied for the detection of gallium in water samples with the relative standard deviation (RSD) ranging from 4.5% to 6.2% (n = 3) and recoveries in the range from 95.3% to 104.9%. [ABSTRACT FROM AUTHOR]

In this study, a novel functionalized magnetic composite (MNCGC) for magnetic solid-phase extraction of bisphenols from environmental and food samples was developed, featuring a multistep synthesis with Fe3O4, chitosan, graphene oxide, and β-cyclodextrin, crosslinked by glutaraldehyde. Characterization confirmed its advantageous morphology, intact crystal structure of the magnetic core, specific surface area, and magnetization, enabling efficient adsorption and separation via an external magnetic field. The optimized MSPE–HPLC–FLD method demonstrated excellent sensitivity, linearity, and recovery rates exceeding 80% for bisphenol pollutants, validating the method's effectiveness in enriching and detecting trace levels of bisphenols in complex matrices. This approach offers a new avenue for analyzing multiple bisphenol residues, with successful application to environmental water and food samples, showing high recovery rates. [ABSTRACT FROM AUTHOR]

In recent years, nanozymes have attracted particular interest and attention as catalysts because of their high catalytic efficiency and stability compared with natural enzymes, whereas how to use simple methods to further improve the catalytic activity of nanozymes is still challenging. In this work, we report a trimetallic metal–organic framework (MOF) based on Fe, Co and Ni, which was prepared by replacing partial original Fe nodes of the Fe-MOF with Co and Ni nodes. The obtained FeCoNi-MOF shows both oxidase-like activity and peroxidase-like activity. FeCoNi-MOF can not only oxidize the chromogenic substrate 3,3,5,5-tetramethylbenzidine (TMB) to its blue oxidation product oxTMB directly, but also catalyze the activation of H2O2 to oxidize the TMB. Compared with corresponding monometallic/bimetallic MOFs, the FeCoNi-MOF with equimolar metals hereby prepared exhibited higher peroxidase-like activity, faster colorimetric reaction speed (1.26–2.57 folds), shorter reaction time (20 min) and stronger affinity with TMB (2.50–5.89 folds) and H2O2 (1.73–3.94 folds), owing to the splendid synergistic electron transfer effect between Fe, Co and Ni. Considering its outstanding advantages, a promising FeCoNi-MOF-based sensing platform has been designated for the colorimetric detection of the biomarker H2O2 and environmental pollutant TP, and lower limits of detection (LODs) (1.75 μM for H2O2 and 0.045 μM for TP) and wider linear ranges (6–800 μM for H2O2 and 0.5–80 μM for TP) were obtained. In addition, the newly constructed colorimetric platform for TP has been applied successfully for the determination of TP in real water samples with average recoveries ranging from 94.6% to 112.1%. Finally, the colorimetric sensing platform based on FeCoNi-MOF is converted to a cost-effective paper strip sensor, which renders the detection of TP more rapid and convenient.

Nanomaterial involving metal and metal oxide signifies a key driver to the implementation of solid phase microextrractor for complete removal of various pollutants residues in water. Nanomaterials combined with porous polymeric membranes like structures e.g. polyurethane foams (PUFs) have also gathered extra attraction to the adoption of water purification because of their ease of management and modifications, surface characteristics, cost-effective, and mechanical, chemical and thermal properties. Thus, this study reports the characterization and impact of Ag and α Fe2O3 nano particles (NPs) individually impregnated PUFs as solid platforms (AgNPs/PUFs, α Fe2O3 NPs/PUFs) for complete retention and consequent quantification of chromium (VI) at low levels in environmental water at pH

The current research is an attempt to analyze on-site selenium(IV) ions in environmental water samples using an eco-friendly miniaturized sensor developed by deposition of a very thin amount of metallic bismuth in a solid Bi electrode tightly closed in miniaturized housing. Numerous experimental variables are optimized, including the composition of the supporting electrolyte and its pH, as well as activation and accumulation conditions. Under optimized measurement conditions, the method shows high sensitivity, permitting a very low limit of detection equal to 7 × 10−10 mol L−1 to be achieved in a short accumulation time of 50 s. The performance of this microsensor was investigated against numerous interference factors and its good anti-interference capability was demonstrated. A series of voltammetric experiments by differential pulse cathodic stripping voltammetry (DPCSV) were carried out and they proved that the miniaturized sensor is characterized by very good accuracy and precision as well as long-term stability. The solid bismuth microelectrode displays a good voltammetric response in the analysis of diverse samples with a complex matrix and demonstrates a good recovery rate.

Herein, a novel polyaniline‐co‐polyindole functionalized magnetic porous carbon derived from MIL‐53(Fe) was prepared and employed as an excellent nano‐adsorbent to preconcentrate trace amounts of nitro‐phenols in water and wastewater samples. Briefly, magnetic MIL‐53(Fe) was synthesized by the addition of magnetite nanoparticles, terephthalic acid, and FeCl3 to the reaction medium. The magnetic MIL‐53(Fe) was pyrolyzed under nitrogen protection to obtain a magnetic porous carbon nanocomposite, and finally, the nanomaterial was functionalized with polyaniline‐co‐polyindole via oxidation polymerization. The obtained nano‐adsorbent was characterized via X‐ray diffraction, Fourier‐transform infrared spectroscopy, vibrating sample magnetometry, and transmission and scanning electron microscopies. After that, the fabricated nano‐material was utilized as an excellent nano‐adsorbent for the preconcentration of trace nitro‐phenols (2‐nitrophenol, 4‐nitrophenol, and 2,4‐dinitrophenol) in environmental water, and wastewater samples. The detection limits were obtained from 0.1 to 0.15 μg/L after performing the optimization process. The new method was in the range of 0.4–300 μg/L. The proposed method exhibited a good precision from 3.2% to 9.6% for within‐day assay, and 5.2%–13.2% for between‐day assay at three concentration levels (1, 50, and 250 μg/L). Eventually, this method was utilized to preconcentrate/determine the target analytes in three water, and wastewater samples, satisfactory (relative standard deviations, 5.4%–9.3%; relative recovery, 88%–109%). [ABSTRACT FROM AUTHOR]

Two homemade silica-based mixed-mode ion-exchange sorbents with strong moieties were compared for the solid-phase extraction (SPE) of a group of pharmaceuticals, drugs of abuse and metabolites. The difference between sorbents was the presence of graphene microparticles embedded in the network and the best results were obtained with the sorbent that did not contain graphene.The optimum SPE protocol of the non-graphene sorbent was: loading pH at 3, different loading volumes depending on the type of sample, 2 mL of MeOH as washing solvent.The optimized method was validated for the analysis of water samples of environmental interest (river water, effluent wastewater and influent wastewater). Apparent recoveries ranged from 22 to 68%, matrix effect values were lower than ±20 for most compounds, and method detection limits ranged from 1 to 28 ng/L and method quantification limits from 2 to 56 ng/L. Precision was obtained as percentual relative standard deviation (RSD%, n=4) and the repeatability and reproducibility between days were always lower than 18%.The sorbent was used to determine the analytes in environmental water samples, where most compounds were found in the range from 2 to 180 ng/L in river samples, from 3 to 2547 ng/L in effluent wastewater samples and from 24 to 8086 ng/L in influent wastewater samples.

This work presents a proposal for an adsorptive stripping voltammetric (AdSV) method for gallium(III) determination at an eco-friendly multiwall carbon nanotube/spherical glassy carbon (MWCNT/SGC) electrode modified with a lead film. The operational factors influencing the sensitivity of the AdSV procedure were thoroughly investigated, and their most favorable values were chosen (0.1 mol L−1 acetate buffer solution pH = 5.6; 7 × 10−5 mol L−1 Pb(II); 2 × 10−4 mol L−1 cupferron; potential/time of lead film formation: −1.9 V/30 s; potential/time of Ga(III)–cupferron adsorption: −0.75 V/30 s). The newly developed MWCNT/SGCE has proven to be a competitive substrate to the glassy carbon electrode to create a lead film electrode, since it allows the determination of gallium in a wider range of concentrations from 3 × 10−9 to 4 × 10−7 mol L−1 with a lower limit of detection equal to 9.5 × 10−10 mol L−1. The elaborated procedure has been shown to be highly selective and insensitive to the presence of an even 100-fold excess of most of the ions commonly found in environmental waters. The MWCNT/SGC sensor, which can maintain >95% of its original response after 70 days of use, has been successfully applied for the detection of gallium in water samples with the relative standard deviation (RSD) ranging from 4.5% to 6.2% (n = 3) and recoveries in the range from 95.3% to 104.9%.

In this study, a novel functionalized magnetic composite (MNCGC) for magnetic solid-phase extraction of bisphenols from environmental and food samples was developed, featuring a multistep synthesis with Fe3O4, chitosan, graphene oxide, and β-cyclodextrin, crosslinked by glutaraldehyde. Characterization confirmed its advantageous morphology, intact crystal structure of the magnetic core, specific surface area, and magnetization, enabling efficient adsorption and separation via an external magnetic field. The optimized MSPE–HPLC–FLD method demonstrated excellent sensitivity, linearity, and recovery rates exceeding 80% for bisphenol pollutants, validating the method’s effectiveness in enriching and detecting trace levels of bisphenols in complex matrices. This approach offers a new avenue for analyzing multiple bisphenol residues, with successful application to environmental water and food samples, showing high recovery rates.

For the first time, highly conductive thickly layered two-dimensional titanium carbide (MXene) was applied as a new coating agent for electromembrane-surrounded solid-phase microextraction (SPME) of triadimenol and iprodione as two model analytes. Preparation of the desired coated electrode was carried out using electrophoretic deposition of MXene on the surface of platinum electrode. Characterization of the prepared coated electrode was conducted using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The coated electrode was located inside a hollow fiber membrane impregnated by 2-nitrophenyl octyl ether as the supported liquid membrane (SLM), while an aqueous solution was injected inside the hollow fiber lumen. Separation and quantification of the analytes were carried out using a gas chromatography instrument equipped with mass spectrometric detection. The effective parameters of the microextraction procedure comprising pHs of sample solution and the acceptor phase, composition of the SLM, extraction time, and the applied voltage were optimized using one-variable at-a-time method. Under the optimal conditions, the calibration curves of the analytes were linear (R 2 > 0.9973) in the range of 0.3–250.0 and 0.5–250.0 ng mL−1 for triadimenol and iprodione, respectively. The limit of detections was determined to be 0.10 and 0.15 ng mL−1 for triadimenol and iprodione, respectively. Repeatability and reproducibility of the method were evaluated by the calculation of intra-day and inter-day relative standard deviations (%). The applicability of the method was evaluated by quantitative analysis of the model analytes in environmental water samples. Relative recoveries in the range of 87.31–102.7% confirmed that the prepared coated electrode can be considered a reliable option in electromembrane-surrounded SPME techniques.

[Display omitted] • Optimized capsule phase microextraction for the determination of PCBs. • Reusable CPME extraction device for PCBs analysis in water samples. • Simple and efficient extraction device in environmental analysis. Due to the adverse effects of polychlorinated biphenyls (PCBs) on human health and ecosystems, their careful monitoring is necessary. In this work, capsule phase microextraction (CPME) combined with gas chromatography-tandem mass spectrometry (GC–MS/MS) was used to extract and determine eight PCBs in water samples. As an extraction device for the CPME procedure, two permeable microporous polypropylene tubes were employed. They contained sol–gel carbowax 20 M (sol–gel CW 20 M) sorbent and a cylindrical magnet. The adsorption and desorption conditions (i.e., type of capsule, sample volume, extraction time, stirring rate, ionic strength, type and volume of eluent, and desorption time) of the microextraction procedure were studied. Under optimum conditions, the extraction was achieved within 20 min using 20 mL of sample at a stirring rate of 1000 rpm, while the elution was performed by immersing the CPME device in 500 μL of acetone for 5 min. Accordingly, the analytical method was validated in terms of linearity, sensitivity, selectivity, enhancement factor, accuracy, and precision, and its greenness and applicability were evaluated. The obtained limits of quantification were equal to 0.010–0.050 μg L−1. The relative recoveries were equal to 91.4 and 110.6 % for intra-day and 88.0–111.2 % for inter-day study, while the relative standard deviation values were better than 10.9 %. Finally, the developed method was used for the analysis of real water samples, proving good fitness-for-purpose. [ABSTRACT FROM AUTHOR]

[Display omitted] • COF-COOH supports the layer of surface molecularly imprinted polymer. • Dummy template in MIP synthesis reduces MET leakage during extraction. • COF-COOH@MIP exhibits fast mass transfer and wide linear range for MET. • COF-COOH@MIP SPE column demonstrates reusability for up to 6 cycles. • HPLC-SPE method with COF-COOH@MIP enables sensitive metamitron analysis in water. Metamitron (MET) is a selective herbicide widely used in agriculture but can persist in the environment and potentially contaminate water resources. This study reports the successful synthesis of a composite adsorbent, COF-COOH@MIP, specifically designed for MET preconcentration via solid-phase extraction (SPE) before high-performance liquid chromatography (HPLC) analysis. COF-COOH@MIP integrates the advantages of covalent organic frameworks (COFs) with their high surface area and stability and molecularly imprinted polymers (MIP) with their tailored recognition cavities. The adsorbent achieved a maximum adsorption capacity of 4.67 μg mg−1. The SPE column packed with COF-COOH@MIP demonstrated excellent reusability, with recovery rates of MET around 100 % after six consecutive cycles. The limit of detection (LOD) and limit of quantification (LOQ) of the established method were remarkably low, at 2.94 ng mL−1 and 9.80 ng mL−1, respectively. The linearity was credible within 0.03-400 μg mL−1 (R2 = 0.9999). The method's applicability to real-world samples was validated by analyzing water from a farm, a ditch, and a river. This method offers a valuable tool for environmental monitoring programs to safeguard water quality from MET pollution. [ABSTRACT FROM AUTHOR]

Abstract The work discusses about the synthesis of indium-alizarin red S complex followed by its application toward the sensing of F¯ ion. At first, the interaction between indium and alizarin red S dye was studied at three different pH medium, pH 4, 7 and 9, of which pH 7 gave the best result. The indium-alizarin red S complex so obtained was then utilized for the ratiometric sensing of fluoride ion using absorption spectroscopy with variation of temperature. The lowest limit of detection (0.040 mM) was obtained at 313 K. The mechanism for the sensing of F¯ ion was then investigated using isothermal titration calorimetry. The endothermic nature of the interaction between F¯ ion with indium-alizarin red S complex shows temperature dependence on the sensing experiment. At the end, the utility of the technique toward natural sample was also examined. The present work reports a simple, rapid and efficient detection of fluoride anion in environmental water samples.

A metal–organic framework UiO‐66 was prepared and used as a sorbent for dispersive solid‐phase extraction combined with high‐performance liquid chromatography (DSPE‐HPLC) for extracting and determining four pyrethroids in water samples for the first time. The as‐synthesized material was confirmed by Fourier transform infrared spectroscopy (FT‐IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and N2 adsorption–desorption analysis. In addition, several important parameters affecting DSPE efficiency, including sorbent dosage, extraction time, salt concentration, pH, elution solvent, elution volume, and elution time, were optimized. Under the optimum conditions, the UiO‐66 based on the DSPE‐HPLC method displayed a wide linear range (10–1000 ng/ml), low limits of detection (2.8–3.5 ng/ml), and good precision (relative standard deviations [RSDs] < 3%) for the four pyrethroids. The recoveries at different spiked levels ranged from 89.3% to 107.7%. In addition, UiO‐66 featured good reusability and reproducibility. The results demonstrated that π–π stacking interactions, hydrophobic interactions, and van der Waals forces between UiO‐66 and the four pyrethroids played a crucial role in the adsorption process. Meanwhile, the maximum extraction capability could be obtained within 5 min. Thus, the DSPE coupled with the UiO‐66 sorbent can be successfully used in the analysis of four pyrethroids in environmental water samples. Practitioner Points: Simultaneous determination of four pyrethroids using the developed UiO‐66‐based DSPE‐HPLC method in water samples.The developed method had a short enrichment time, broad linear ranges, a low detection limit, and high enrichment factor.It is showed that π–π stacking interaction, hydrophobic interaction, and van der Waals forces were the main mechanism. [ABSTRACT FROM AUTHOR]

Cyanide toxicity in water significantly threatens public health and the environment. To address this, a miniaturized simple, low-cost, selective and sensitive direct dual wave β-correction spectrophotometric probe has been established for cyanide detection in water. The dual-wavelength β-correction spectrophotometry enhances the selectivity and sensitivity of the probe in the presence of interfering species. The assay relies a highly selective nucleophilic addition of cyanide ions to dithizone (H 2 Dz) as chromogenic reagent in aqueous media of pH 6.8-7.2, forming a red-colored cyano H 2 Dz adduct. The electronic spectrum of the formed adduct displays a sharp absorption peak at λ max  = 480 nm, enabling precise colorimetric detection. The molar absorptivity and Sandell's sensitivity index for the cyano H 2 Dz adduct with and without β-correction spectrophotometry were 5.62 × 10 3 , and 1.79 × 10 3 L mol - 1 cm - 1 , and 0.002 and 0.0033 µg cm - 2 , respectively. Beer's law and Ringbom's plots are valid in the range 0.01-5.0 and 0.06-2.0 µg mL - 1 CN - concentration, respectively. The limits of detection (LOD) and quantification (LOQ) improved from 1.03 × 10 -1 and 3.13 × 10 -1 μg/mL using ordinary spectrophotometry to 2.8 × 10 -2 and 8.7 × 10 -2 μg mL -1 employing β-correction spectrophotometry. The probe offers rapid response, good anti-interference ability, reproducibility, and cost-effectiveness. The probe was successfully applied for detection of trace levels of cyanide ions in water with good repeatability. It has been also validated in water samples with good recoveries (99.2 ± 5.02 %). The experimental Student t test (t exp  = 1.2-1.5) was lower than the critical (t exp  = 2.78) at 95 % probability (n = 5). The stoichiometry and mechanism of formation of the cyano adduct were assigned and addressed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

In this work, the use of a hydrophobic natural deep eutectic solvent (NADES) as supported liquid membrane (SLM) for hollow fiber liquid-phase microextraction (HF-LPME) of sulfonamides is proposed. Different NADES based on l-menthol and naturally occurring organic acids (citric acid, formic acid, acetic acid, decanoic acid, nonanoic acid, lactic acid, valeric acid, isobutyric acid, hexanoic acid, octanoic acid, and 2-methylbutyric acid) were prepared at different molar ratios. Important solvent properties to work as SLM were studied such as stability in the fiber and compatibility with HPLC. Then, the ability of the prepared NADES to extract 8 antibiotics of the family of sulfonamides (SAs) from water by HF-LPME was studied. From them, the combination of formic acid:L-menthol (1:1) was selected as optimum since it provided a better and more balanced extraction of SAs. The optimized HF-LPME procedure was applied to the analysis of an artificial water containing humic acids, tap and river water samples, showing a good clean-up ability for all the tested samples. Calibration curves showed good linearity for all the SAs and samples with linear regression coefficients (r2) greater than 0.992. Relative recoveries ranged from 53 to 121%, with relative standard deviation values between 5 and 21%, depending upon the analyte and type of water sample. The limits of detection of the method varied from 0.63 to 2.85 µg/L for tap water, 0.70 to 3.23 µg/L for the Jarama river and 0.61 to 2.52 µg/L for the Manzanares river. Besides, the proposed method can be considered sustainable, according to AGREEprep tool, and greener than reported methods in the literature based in other microextraction techniques.

In the present study, electrospun zeolitic imidazolate framework-8/poly(lactic acid) nanofibers were successfully synthesized and characterized as a potential nanosorbent for the pipette-tip micro-solid phase extraction of chlorpropham, pirimicarb, carbaryl, and methiocarb carbamate insecticides from environmental water samples. The extraction procedure was followed by gas chromatography/mass spectrometry separation and determination of the target analytes. All the effective parameters of the extraction procedure were optimized through the one variable at-a-time method. Thanks to the very simple extraction procedure as well as the application of electrospun nanofibers with high surface area, the four analytes were efficiently extracted with as lowest extraction times as practicable. Under the optimal conditions, the calibration plots of the analytes were obtained within broad linear dynamic ranges of 0.5 – 150 ng mL−1 for chlorpropham and pirimicarb plus 1.0 – 175 ng mL−1 for carbaryl and methiocarb, respectively. Besides, limits of detection as low as 0.2 and 0.15 ng mL−1 for chlorpropham and pirimicarb, respectively, as well as 0.5 ng mL−1 for carbaryl and methiocarb indicate the favorable sensitivity of the analytical procedure. The applicability of the developed method was evaluated by quantitative determination of the target analytes in four different environmental water samples. Relative recoveries higher than 88.0% shows the acceptable accuracy of the method in the quantitative determination of the four carbamate insecticides.

In this work, the preparation and evaluation of water‐compatible molecularly imprinted polymers for triazines using 2‐hydroxyethyl methacrylate and methacrylic acid as comonomers is described. Four sets of molecularly imprinted and non‐imprinted polymers for propazine were prepared at varying monomer molar ratios (from 4:0 to 1:3), and evaluated for the recognition of several triazines directly in aqueous media. The evaluation was performed by loading 1 mL of an aqueous solution containing 500 ng of each selected triazine, washing with 500 μL of acetonitrile, and eluting with 500 μL of methanol followed by 2 × 500 μL of a solution of methanol containing 10% of acetic acid. Final determinations were performed by high‐performance liquid chromatography‐ultraviolet detection. Improvement in molecular recognition of triazines in water was obtained on those molecularly imprinted polymers incorporating 2‐hydroxyethyl methacrylate in 3:1 or 2:2 molar ratios, being the former selected as optimum providing recoveries for propazine up to 80%. A molecularly imprinted solid‐phase extraction protocol was developed to ensure that triazines‐selective recognition takes place inside selective binding sites in pure water media. Finally, the developed method was successfully applied to the determination of the selected triazines in environmental waters providing limits of detection from 0.16 and the 0.5 μg/L concentration range. [ABSTRACT FROM AUTHOR]

This study reports a deep eutectic solvent based dispersive liquid-liquid microextraction (DES-DLLME) to extract aromatic amines (4-chloroaniline, 3-nitroaniline, 2-naphtylamine) in environmental water samples before their HPLC-UV determination. The hydrophobic deep eutectic solvent (DES) was prepared by mixing bis(2-ethylhexyl) phosphate (BEHP) as a hydrogen bond acceptor and phenol as a hydrogen bond donor. Affecting factors on the extraction of the aromatic amines were investigated and optimized. Optimum conditions were: DES type: BHHP-Ph ratio: 1 to 2; pH of solution: 8.0; DES volume: 80 µL, salt amount: 10% (w/v). Under optimum conditions, the developed method showed a wide linear range of 0.2–200 µg L−1 (R2 ≥ 0.99) with satisfactory recoveries (≥90.0%). The limit of detections (LODs) and limit of quantifications (LOQs) were in the range of 0.07–0.17 µg L−1 and 0.2–0.5 µg L−1, respectively. The enrichment factors were 170, 180 and 190 for 4-chloroaninile, 3-nitroaniline, 2-naphtylamine, respectively. Based on obtained results, the proposed method is straightforward, efficient, sensitive, and eco-friendly for the extracting and determining of the aromatic amines in environmental water samples.

[Display omitted] • SFOD–based air–assisted LLME method for trace pesticide residues was developed. • Extraction and preconcentration of multiclass pesticides was found efficient. • Analysis of pesticides in water samples and soft drinks confirmed reliability. • Determination of multiclass pesticides residues was achieved by HPLC–DAD. • Simple, sensitive and efficient method with high extraction recovery was developed. A fast, simple, efficient and selective surface floating organic droplet–based air–assisted liquid–liquid microextraction method coupled with high performance liquid chromatograph–diode array detector was developed for simultaneous extraction of six multiclass pesticides. The developed method was validated for the extraction, enrichment and quantitative determination of trace level multiclass pesticides from environmental water, mineral water and soft drink samples. The effect of experimental parameters such as type and volume of extraction solvent, addition of salt, solution pH and extraction number were successfully optimized. Under the optimum conditions, the method showed good linearity for all the six multiclass pesticide residues with coefficient of determination within the range of 0.9979–0.9994. The limit of detection and quantification were in the range 0.01 to 0.07 µg L−1 and 0.03 to 0.25 µg L−1, respectively. The reproducibility and repeatability study in terms of %RSD were in the range of 0.88–5.28 and 1.35–6.08, respectively, indicating good precision of the method. The method exhibited acceptable mean relative recovery (%RR) in the range of 71.82 to 110.16 % with %RSDs (n = 3) less than 8 % for all the samples. Thus, the developed method could be utilized as selective extraction and preconcentration of multiclass pesticides from environmental water samples, mineral water and soft drink samples, as well as samples with similar matrices. [ABSTRACT FROM AUTHOR]

Mercury is a highly toxic metal, of which even small doses (<200 ng mL−1) can cause serious problems for humans, plants, animals and microorganisms, including marine species and freshwater organisms. Hence, a simple, fast, highly selective and sensitive and accurate method for the detection of mercury in the environmental, clinical or biological samples is necessary. A new, sensitive and selective method for the determination of Hg(II) with 5 % N1‐hydroxy‐N1,N2‐diphenylbenzamidine modified carbon paste electrode has been developed. Hg(II) was accumulated for 210 s on the surface of the modified electrode using 0.1 M CH3COONa of pH 7 at −0.8 V vs Ag/AgCl, followed by electrochemical stripping with SWASV in 0.1 M NH4Cl at pH 4. The linear range is 0.02–10 μM Hg(II) with limit of detection of 1.28 nM. The method has RSDs of 3.7 %. The method was applied for the determination Hg(II) in five types of water samples. The recoveries were in the range 97.8–103 %. The proposed method was found to be highly selective and sensitive and has many attractive features compared to previous reports such as low cost, simplicity of electrode preparation, long term stability, fast response, easy renewable ability, and reasonable short accumulation time. [ABSTRACT FROM AUTHOR]

A sensitive and selective mixed hemimicelles solid phase extraction magnetic material based on sodium dodecyl sulfate-coated magnetite (Fe3O4)/alumina (Al2O3) is proposed for the preconcentration and determination of atrazine and simazine. Atrazine and simazine were preconcentrated on the composite solid phase as an adsorbent and then determined by high performance liquid chromatography. Several parameters influencing the recoveries of the analytes were investigated. The experimental results showed that it was possible to obtain the highest extraction efficiency when the solution pH and extraction time were 1.5 and 1 min, respectively, using 100 mL of validation solution containing 1.0 μg of triazines and 1 mL of acetonitrile as an eluent. Recoveries of atrazine and simazine were 72 ± 1% and 77 ± 3% with relative standard deviations for 5 determinations of 1.6 and 3.8%, respectively, under optimum conditions. The linear ranges of calibration curves for triazines were from 1 to 20 ng/mL with correlation coefficients of 0.995 (atrazine) and 0.991 (simazine) and the detection limits (signal-to-noise ratio of 3) were 0.11 and 0.17 ng/mL for atrazine and simazine, respectively. The proposed method was successfully applied to the determination of triazines in environmental water samples such as river, tap and pond waters with high precision and accuracy. [ABSTRACT FROM AUTHOR]

hER-MIP is a molecularly imprinted polymer (MIP) that has been shown to selectively collect human estrogen receptor (hER) binding active substances. However, environmental samples contain various chemicals depending on the location and regional differences, and the hER binding activity depends on the sample type. Thus, the general applicability of hER-MIP to actual environmental samples must be elucidated. In this study, 48 environmental samples were collected and screened with hER-MIP, and a yeast assay was performed to evaluate the adsorption characteristics of the samples according to the adsorption and elution fractions. The results showed that hER-MIP collects hER binding active substances almost selectively but does not collect constitutive androstane receptor (CAR) binding active substances selectively. CAR binding activity was detected in the adsorbed fraction because several hER binding active substances also demonstrate CAR binding activity. [ABSTRACT FROM AUTHOR]

Achieving simultaneous determination of antibiotic multiresidues in environmental waters by solid phase extraction (SPE) coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) with detection limits ≤ ng L-1 is still a huge challenge. Moreover, the offline SPE procedure was performed manually, costly, and time-consuming, while the online SPE required precision pretreatment instruments that require highly-skilled personnel. In this paper, a fully automated SPE coupled with UHPLC–MS/MS method was developed for analysis of antibiotics (sulfonamides, quinolones, and macrolides) in water matrices. Sample preparation optimization included SPE materials and configuration (HLB disks), sample volume (500-1000 mL), and pH (pH = 3) with a flow rate at 2~5 mL min-1, and an elution procedure with 2 × 6 mL methanol, and 2 × 6 mL acetone. Meanwhile, the parameters for UHPLC-MS/S detection of analytes were optimized, including LC retention time, and MS parameters. The instrumental limits of detection (LOD) and quantification (LOQ) of analytes ranged from 0.01-0.72 μg L-1 and 0.05-2.39 μg L-1, respectively, with satisfactory linear calibration (R2 > 0.995) and precision (< 9.9%). Recoveries in spike samples ranged between 77.5-104.9% in pure water, 59.4-97.8% in surface water (SW), and 58.2-108.6% in wastewater effluent (WWE) with relative standard deviations ≤ 12.8%. The matrix effects observed for most analytes were suppression (0-28.1%) except for five analytes having presented enhancement (0-14.6 %) in SW or WWE. This method can basically meet the needs of trace antibiotic residues detection in waters, with examples of concentrations of detected antibiotics being lower than LOQ (LLQ) -94.47 ng L-1 in WWEs and LLQ-15.47 ng L-1 in SW in the lower reaches of the Yangtze River Basin. [ABSTRACT FROM AUTHOR]

A simple and efficient method to detect and quantify Fe(II) and Au(III) cations in environmental water samples was developed. The detection principle is based on the 1:1 mol‐ratio complex formation between the probe molecule (tannic acid, TA) and Fe(II)/or Au(III), which yields visual color change and strong light absorbance at 518 nm and 534 nm, respectively. The association constant Ka for Fe(II) and Au(III) cations 4.01 × 104 and 4.13 × 104 M−1, respectively, was determined from Benesi–Hildebrand plot, indicating strong interactions between TA and target ions. This TA probe performed well in 50 mM phosphate buffer (PB, pH 9.0) solution and demonstrated an outstanding selectivity over 16 potential interfering metal ions and a good selectivity over Fe(III). The linear range in this study for Fe(II) and Au(III) cations was 0.25–100 μM and 1.0–100 μM, respectively. The detection limit of the TA probe for Fe(II) and Au(III) cations was found to be 0.080 and 0.50 μM, respectively. The spike recovery for both metal ions in three environmental aqueous samples (spring water and pond water) was ranged 90.2%–117.2%. This study demonstrated that the TA probe is a simple and convenient detection method for analyzing water samples obtained from fresh water sources. [ABSTRACT FROM AUTHOR]

In this paper, a flower‐like molybdenum disulfide material was prepared by hydrothermal method and was first used as adsorbents in the solid‐phase extraction process for enriching N‐nitrosoamines. Molybdenum disulfide exhibited three‐dimensional petal‐like microspheres with about 500 nm in diameter. The relevant analyte extraction and elution parameters (sample volumes, solution pH, washing solvents, elution solvents, and elution volumes) were optimized to improve the solid‐phase extraction efficiency. The solid‐phase extraction process coupled with high‐performance liquid chromatography‐tandem mass spectrometry for determining N‐nitrosoamines in environmental water samples was established. The limits of detection were in the range of 0.01–0.05 ng/mL. The satisfactory recoveries (68.9–106.1%) were obtained at three different spiked concentrations (2, 5, and 8 ng/mL) in water samples, and the relative standard deviations were between 1.96 and 8.38%. This proposed method not only showed high sensitivity and good reusability but also provided a new adsorbent for enriching trace N‐nitrosoamines in environmental water samples. [ABSTRACT FROM AUTHOR]

In this work, surface‐enhanced Raman spectroscopy (SERS) was employed for the quantification of sulfide anion (S2−) in aqueous samples. Silver nanoparticles modified with trithiocyanuric acid were used as the SERS enhancing substrate. To address the problem of poor reproducibility of SERS signal caused by the uncontrollable variations in physical properties of enhancing substrate, the performance of several calibration models for quantitative analysis of the SERS measurements of S2− samples were evaluated and compared. The calibration models studied were univariate ratiometric model based on the intensity ratio between the characteristic SERS peaks of trithiocyanuric acid, PLS models built on the raw and preprocessed SERS measurements, and the generalized ratiometric indicator based multiplicative effects model (MEMGRI). Experimental results showed that among the calibration models considered in this contribution, only MEMGRI model achieved accurate and precise concentration predictions for S2− in the spiked environmental water samples with recovery rates varying within the range of 94% to 106%. Therefore, it is reasonable to expect that the combination of SERS technique with MEMGRI model may be a competitive alternative for quantitative analysis of environmental samples. [ABSTRACT FROM AUTHOR]

Oxazepam, one of the most frequently prescribed anxiolytic drugs, is not completely removed from wastewater with conventional treatment processes. It can thus be found at trace levels in environmental water, with human urine constituting the major source of contamination. This study focused on the development and characterization of molecularly imprinted polymers (MIPs) for the selective solid-phase extraction of oxazepam at trace levels from environmental water and human urine samples. Two MIPs were synthesized, and their selectivity in pure organic and aqueous media were assayed. After optimizing the extraction procedure adapted to a large sample volume to reach a high enrichment factor, the most promising MIP was applied to the selective extraction of oxazepam from environmental water. Extraction recoveries of 83 ± 12, 92 ± 4 and 89 ± 10% were obtained using the MIP for tap, mineral and river water, respectively, while a recovery close to 40% was obtained on the corresponding non-imprinted polymer (NIP). Thanks to the high enrichment factors, a limit of quantification (LOQ) of 4.5 ng L−1 was obtained for river water. A selective extraction procedure was also developed for urine samples and gave rise to extraction recoveries close to 95% for the MIP and only 23% for the NIP. Using the MIP, a LOQ of 357 ng L−1 was obtained for oxazepam in urine. The use of the MIP also helped to limit the matrix effects encountered for the quantification of oxazepam in environmental samples and in human urine samples after extraction on an Oasis HLB sorbent. [ABSTRACT FROM AUTHOR]

The work discusses about the synthesis of indium-alizarin red S complex followed by its application toward the sensing of F¯ ion. At first, the interaction between indium and alizarin red S dye was studied at three different pH medium, pH 4, 7 and 9, of which pH 7 gave the best result. The indium-alizarin red S complex so obtained was then utilized for the ratiometric sensing of fluoride ion using absorption spectroscopy with variation of temperature. The lowest limit of detection (0.040 mM) was obtained at 313 K. The mechanism for the sensing of F¯ ion was then investigated using isothermal titration calorimetry. The endothermic nature of the interaction between F¯ ion with indium-alizarin red S complex shows temperature dependence on the sensing experiment. At the end, the utility of the technique toward natural sample was also examined. The present work reports a simple, rapid and efficient detection of fluoride anion in environmental water samples. [ABSTRACT FROM AUTHOR]

A magnetic dispersive micro-solid-phase extraction as a simple and efficient sample preparation procedure was developed to extract lead (II) and cadmium (II) ions. The microextraction method was enhanced using an ultrasonic bath as a suitable device and a surfactant as a dispersion agent to disperse a sorbent into a low volume of distilled water before injecting it into the sample solution. This procedure increases the sorbent dispersion efficiency and decreases the dispersion time to reduce sorbent degradation. Also, green and selective sorbent (magnetic CoFe2O4 nanoparticles @ SiO2 @ 4-aminobenzoic acid-functionalized graphene oxide) was prepared based on functionalization of graphene oxide with 4-aminobenzoic acid and its magnetization with CoFe2O4 nanoparticles using the solgel technique. Several factors affecting the microextraction process of lead (II) and cadmium (II) ions, including the type of desorption solvent and dispersing solvent, extraction time, desorption time, dispersion time, sample solution volume, sorbent amount, and pH of the solution, were optimized by experimental design and one factor at a time strategy. Under the optimum condition, the calibration curves for the determination of lead (II) and cadmium (II) ions were linear at the concentration ranges of 13.2–235.0 and 16.8–240.0 ng L−1 with a determination coefficient (R2) of 0.9866 and 0.9839, respectively. Limit of detection and relative standard deviation (n = 3) for the determination of lead (II) and cadmium (II) ions were lower than 5.4 ng L−1 and 4.2%, respectively. The application of the method for analyzing several real water samples indicated that the technique has an excellent relative recovery in the range of 96.2–102.2% with relative standard deviations of less than 4.9%. [ABSTRACT FROM AUTHOR]

A simple, green and rapid method for the simultaneous determination of three kinds of quinolone antibiotics (QNs) from environmental water samples and biological samples was established by monolithic spin columns-solid phase extraction coupled with high performance liquid chromatography (MSC-SPE-HPLC). The QNs was completely adsorbed by 300 mg spent coffee grounds as the sorbents of MSC-SPE at 1000 rpm, and eluted by 2500 μL acetonitrile and 4% acetic acid (60:40, V:V). The efficient and rapid elution was obtained under the speed of 500 rpm. After separation on a Pursuit 5 C18 column (250 mm×4.6 μm, 5 μm), the samples were determined. The three QNs showed good liner relationship in the range of 0.1-10 μg/mL with the correlation coefficients greater than 0.998. The limit of detection (LODs, S/N=3) for ciprofloxacin, norfloxacin and enrofloxacin was 33.3 ng/mL.Moreover, the recoveries were 70.3- 112.6% at three spiked levels (0.5, 1 and 2 μg/mL) with the relative standard deviation 1.02- 9.78%. The obtained results revealed that the method was simple to operate, green and environment-friendly, and could be used for the determination of antibiotics in environmental samples. [ABSTRACT FROM AUTHOR]

In this present work, an exceptionally specific and selective chemosensor (Z)-5-((pyren-1-ylmethylene)amino)-1,3,4-thiadiazole-2-thiol (PCAT), has been designed and synthesized via simplest synthetic route. The synthesized probe is successfully portrayed by utilizing ¹H, 13C NMR, ESI-MS techniques. The PCAT probe indicates colour changes which can be seen through naked-eye from colourless to pink and fluorescence turn-on response specifically towards Pb2+ ions with the possible contending metal ions. The binding stoichiometric proportion has been found as 1:1 from the Job's plot investigation. The detection limit for PCAT-Pb2+ ions is found to be 7.15×10-8 M. Besides, the real sample analysis is also done with the collected ecological water samples and has resulted in an excellent recovery percentage. [ABSTRACT FROM AUTHOR]

A simple and precise RP-HPLC method has been developed and validated for the separation and trace determination of selected food colorant residues, namely, Tartrazine (E102), Sunset Yellow (E110) and Allura Red (E129), in water samples. The colorants were separated in less than five minutes using buffered distilled water as a mobile phase on a superheated hybrid ODS X-Bridge RP-C18 column (150 × 3.5 µm, 4.6 mm i.d.). Van't Hoff plots were linear for all the tested colorants at different mobile phases and without any significant changes in their retention factors or the transition stage of the stationary phase. The lower limits of detection for E102 and E110 were found to be 0.5 and 0.016 mg/mL, respectively, whereas for E129 it was 0.0004 mg/mL. The proposed method was checked for its accuracy and precision and was applied to determine the selected colorants in soft drinks and environmental water samples with acceptable recoveries in the range from 83.5 ± 1.9 to 114 ± 3%. [ABSTRACT FROM AUTHOR]

Dispersive liquid‐liquid microextraction has garnered increasing attention in sample preparation due to its rapid and efficient extraction process. In this study, a new terpineol‐based hydrophobic deep eutectic solvent was firstly synthesized by mixing α‐terpineol with 1‐octanoic acid, and then applied to analysis of phenols from water samples by dispersive liquid‐liquid microextraction combined with high‐performance liquid chromatography and diode array detection. Infrared spectroscopy indicated that hydrogen bonding was responsible for the formation of deep eutectic solvent between α‐terpineol and 1‐octanoic acid. After optimization of several parameters, such as the type and volume of deep eutectic solvent and the disperser, pH and ionic strength of sample solution, the developed method exhibited excellent extraction performance to the phenols with the enrichment factors from 27 to 32. Good linearity was acquired ranging from 5 to 5000 μg/L, and detection of limits of the proposed method for the phenols ranged from 0.15 to 0.38 μg/L. The recoveries measured by spiked samples at three concentration levels ranged from 81.6 to 99.3%, and precision was found with intra‐ and inter‐day relative standard deviations less than 8.7 and 9.2%, respectively. Finally, the proposed method was successfully applied to the determination of the phenols in environmental water samples. [ABSTRACT FROM AUTHOR]

• A one-step method for rapid preparation of functional MOF composites was designed. • The UiO-66-NH 2 -AMPS exhibited higher and faster adsorption for tylosin. • Hydrogen bond and electrostatic interaction were the primary recognition force. • The UiO-66-NH 2 -AMPS possessed outstanding adsorption performance and regeneration. Functional metal organic framework composite can effectively remove antibiotics from environmental water samples. However, designing excellent adsorbents with multiple active sites via a rapid one-step method is still a challenging problem. A novel metal organic framework composite (UiO-66-NH 2 -AMPS) was synthesized through one-step polymerization by adding functional monomer 2-acrylamide-2-methylpropanesulfonic acid (AMPS) during the preparation of UiO-66-NH 2. The microstructure and morphology of the UiO-66-NH 2 -AMPS composite were characterized, and the adsorption performance towards tylosin (TYL) in water was explored by equilibrium adsorption experiment. The results illustrated that the adsorption equilibrium can be reached within 1 h, and the maximum binding amount of UiO-66-NH 2 -AMPS for TYL was 161.60 mg g−1, which was approximately 2.1–329 times of that of the other adsorbents. The pseudo second-order kinetic and Liu isotherm model were suitable for the adsorption process, and thermodynamic study displayed that the adsorption of UiO-66-NH 2 -AMPS composite for TYL is spontaneous and endothermal. The infrared and X-ray photoelectron spectra exhibited that hydrogen bond and electrostatic interaction were the primary recognition force for TYL. The UiO-66-NH 2 -AMPS composite have been successfully applied to remove TYL from environmental water. After 5 cycles, the removal efficiency of UiO-66-NH 2 -AMPS was still above 91.30%. [ABSTRACT FROM AUTHOR]

Taking the advantages of surface imprinting, multi-template imprinting and magnetic separation, a novel magnetic multi-template molecularly imprinted polymer (mag-MMIP@MWCNTs) was prepared by using MWCNTs as support material, Fe3O4 as magnetic core, and dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP) as template molecules. This composite was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and the Brunauer-Emmett-Teller (BET) analysis, and was used for the simultaneous adsorption of DMP, DEP, and DBP in aqueous solution. The effects of solution pH, contact time, PAEs initial concentration, temperature, adsorption selectivity, and reusability were investigated and discussed in detail. The results demonstrated that mag-MMIP@MWCNTs exhibited fast kinetics, good magnetic separation, and excellent selectivity for the adsorption of three phthalate esters (PAEs). The adsorption kinetics followed pseudo second-order kinetic model and the adsorption thermodynamics followed Langmuir isothermal model very well, and the maximum adsorption capacities (Qmax) of DMP, DEP, and DBP were obtained as 0.95, 1.38, and 7.09 mg g-1, respectively. The Scatchard analysis revealed that the template-polymer system had a two-site binding behavior. The adsorption thermodynamic studies indicated that the adsorption processes were exothermic and spontaneous, and dominated by physical adsorption relying on hydrogen bond, hydrophobic interaction, and van der Waals force. Mag-MMIP@MWCNTs also showed good reproducibility and reusability for simultaneous adsorption of the three PAEs. The potential application of mag-MMIP@MWCNTs was proved by the removal of DMP, DEP, and DBP spiked in environmental water samples. [ABSTRACT FROM AUTHOR]

Removal of 137Cs radionuclides from the environment has engrossed the concern of researchers after Fukushima accident. The leakage of radioactive cesium ions can lead up to surface and groundwater contamination, and this leads to pollution of drinking water sources. In this work, corchorus olitorius stalks has been used as a novel precursor for production of low-cost mesoporous activated carbon (Meso-AC) and HNO3/H2O2-modified Meso-AC (m-Meso-AC). The physicochemical properties of all adsorbents were evaluated. The influences of sorption parameters and presence of some ligands (humic acid, fulvic acid, and EDTA) on the sorption of 137Cs were studied. The maximum 137Cs capacity of m-Meso-AC was found to be 58.74 mg/g. Efficiency of the new adsorbent to remove 137Cs radionuclides from natural waters (tap, river, and groundwater) was investigated. The studies showed that new adsorbent could be used as promising material for the retention of 137Cs from real radioactive waste and natural water samples. [ABSTRACT FROM AUTHOR]

In view of large-scale production, usage and toxic nature, the synthetic dyes are a very significant category of pollutants. This work reports the preparation and application of reduced graphene oxide/cobalt oxide (rGO/Co3O4) nanocomposite as selective and regenerable magnetite nanosorbent for the preconcentration and determination of brilliant green (BG) as a synthetic dye by UV–Vis spectrophotometry. The properties of the rGO/Co3O4 nanocomposite were characterized by UV–Vis spectrophotometry, Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, vibrating sample magnetometer and inductively coupled plasma optical emission spectrometry. Magnetic dispersive microsolid phase extraction (MD-μSPE) as a green, simple and sensitive method has been proposed for the separation and determination of trace quantities of BG. The experimental parameters affecting the MD-μSPE efficiency for the target analytes such as sample pH, brilliant green concentration, adsorbent dose and sonication time were investigated and optimized by central composite design coupled with desirability function approach. Under the optimized conditions, the detection limit, relative standard deviation and enrichment factor were 2.6 ng mL−1, 3.34% (n = 5) and 24.5, respectively. Finally, the applicability of the proposed method was successfully evaluated by the determination of trace amounts of BG in fish breeding pool and tap water samples. [ABSTRACT FROM AUTHOR]

Herein, we report a rapid and sensitive colorimetric detection of Hg2+ by designing a specific DNA probe with phosphorothioate RNA modification (PS-probe) for Hg2+ recognition and utilizing DNA-modified gold nanoparticles (DNA-AuNPs) as the transducer. The distance between two DNA-AuNPs is controlled by a linker DNA, providing the linker DNA-regulated aggregation or dispersion status of AuNPs in solution. Exonuclease III (Exo III) can trigger the recycled digestion of linker DNA strands, inhibiting the reformation of aggregated nanoparticles and hence leading to a color shift from purple to red. However, the Hg2+-induced cleavage of the PS-probe can efficiently prevent the digestion of linker DNA strands by Exo III and hence reassemble the modified AuNPs to form aggregates in purple color. Thus, a positive correlation between the linker DNA strands left and the addition of Hg2+ provides a quantitative basis for Hg2+ sensing. A linear range of A520/A700 versus Hg2+ concentration is achieved in the range 2–100 nM associated with a detection limit as low as 1.30 ± 0.04 nM. Moreover, the biosensor exhibits excellent selectivity for Hg2+. The strong selectivity behavior was confirmed by recoveries ranging from 96 to 114% in real water samples. [ABSTRACT FROM AUTHOR]

In this research, a simple, rapid, and ecofriendly magnetic nanoparticles (MNPs)-based ultrasound-assisted micro-solid-phase extraction (US-µ-SPE) method has been proposed for simultaneous determination of five heavy metal ions [Cu(Π), Ni(Π), Pb(Π), Co(Π), Cd(Π)] in environmental water samples. Here, CoO–Fe2O3@SiO2@TiO2 NPs were synthesized as an efficient adsorbent with excellent adsorption capacity, high dispersion ability and super-magnetic property for the adsorption of the ions. The parameters influencing the extraction efficiency were evaluated and optimized by statistical experimental design. The pH of sample solution, sonication time, dosages of adsorbent, and the volume, concentration and type of elute are 6.50, 14.2 min, 5.5 mg; 300 µL, 2 mol L−1 of HNO3, respectively. Moreover, the reusability for MNPs was six times. The target ions were successfully quantified using a micro-sampling flame atomic absorption spectrometry (MS-FAAS) technique in five different real water samples: tap water, lake water, river water, well water and distilled water. For all studied metal ions, the proposed method provided high recoveries (94.6–103%), high R2 (0.9993–0.9998), low LODs (0.03–0.18 µg L−1) and repeatability (RSD% = 1.49–3.59). [ABSTRACT FROM AUTHOR]

The study of biologically important Cu2+ and S2− ions has drawn great attention in the recent years since an abnormal level of these ions is an indication for health impairment. Therefore, a reliable strategy for effective fluorescence determination of Cu2+ and S2− ions was developed. Simply, the method based on economical plant-dependent thermolysis procedure for efficient green synthesis of water dispersible luminescent polyamine-based carbon dots (PA@C-dots) utilizes Vitis vinifera juice as precursor with a high quantum yield (32.1%) and good photo-stability. The fluorescent PA@C-dots were characterized by different spectroscopical, physical, and structural techniques. Furthermore, the synthesized PA@C-dots can be used as an efficient dual functional fluorescent probe for the sensitive and selective estimation of Cu2+ and S2− ions. The incorporation of Cu2+ ions and their adsorption on the surface of PA@C-dot skeleton leads to the respectable fluorescence quenching of C-dots (turn-off mode). The Cu2+-PA@C-dot was found to be sensitive to S2− ions. The addition of S2− recovers the fluorescence (turn-on mode) of Cu2+-PA@C-dots, thanks to its capacity for withdrawing Cu2+ from the shell of PA@C-dots. Fluorescence quenching in the range of 0.07–60 μM Cu2+ was obtained with LOD and LOQ of 0.02 and 0.066 μM, respectively. Sulfide detection provides linearity in the range of 0.8 to 95 μM with LOD and LOQ of 0.24 and 0.79 μM, respectively. The optimal excitation and emission wavelengths for all experiments are 435 nm and 498 nm, respectively. Experiment results elucidate that the proposed method is suitable for Cu2+and S2− ion detection in environmental water samples. [ABSTRACT FROM AUTHOR]

A major goal of green chemistry is to avoid the use of toxic organic solvents. In particular, there are few green methods allowing extraction and quantification of chromium species in environmental samples. Here, we developed home-made, dual-gel electromembrane extraction combined with a microfluidic paper-based analytical device for the simultaneous determination of Cr(III) and Cr(VI) in water, without using any organic solvent. The positively charged Cr(III) and negatively charged Cr(VI) migrated selectively into the cathodic (pH 2.0) and anodic (pH 3.0) aqueous acceptor phases, respectively. After extraction, the anodic acceptor phase containing Cr(VI) was analyzed directly by a microfluidic paper-based analytical device, after the addition of the diphenylcarbazide colorimetric reagent. The cathodic acceptor phase containing Cr(III) was mixed with Ce(IV) to oxidize Cr(III) to Cr(VI), and then, Cr(VI) ions were detected on the microfluidic paper-based analytical device after adding diphenylcarbazide. Under the optimized conditions, limits of detection of 2.0 and 3.0 ng/mL and extraction recoveries of 58.8% and 83.3% were achieved for Cr(VI) and Cr(III), respectively. [ABSTRACT FROM AUTHOR]