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Owing to the high cost and unavailability of different analytical techniques, there is an urgent need to develop new techniques not only for detecting but also removing mercury ions in real samples. Thus, an optical chemical sensor based on the anchoring of phenanthraquinone monophenylthiosemicarbazone in a plasticized cellulose triacetate membrane was fabricated and applied to the recognition and removal of mercury ions from aqueous solutions. The synthesized optode was characterized by FT-IR, SEM, AFM, and thermal analysis. Several parameters, including the pH, temperature, contact time, washing solvent, and washing time, were optimized. Under optimal conditions, a promising optode film platform was utilized for sensing mercury ions, and the concentrations were calculated based on colorimetric analysis (Histogram, RGB) of digital images, visualization, and spectrophotometry. Also, an optical optode was used for complete adsorption of mercury ions from aqueous solutions. In addition, the regeneration of the synthesized optode was evaluated using 0.1 mol L− 1 nitric acid, which effectively removed all adsorbed mercury ions. The obtained data indicated good linearity in the sensing and adsorption of Hg2+ over a concentration range of 0.005–5000 µgL− 1 with a low limit of detection (LOD = 0.066 µgL− 1) and limit of quantification (LOQ, 0.22 µgL− 1). Furthermore, it showed good distinctions in the presence of coexisting ions, high stability (five months), good applicability, and reproducibility (RSD = 1.31%), making it a promising sensor for Hg2+ detection. On the other hand, the kinetic studies revealed that the pseudo-second-order was the best model for describing the adsorption behavior of mercury ions on the optode surface. Also, the thermodynamic parameters indicate spontaneous (ΔG0 < 0) and endothermic (ΔH0 < 0) reactions. Also, the maximum adsorption capacity was found to be 73.2 mg g− 1. Thus, the optodes were successfully applied for the detection and/or removal of Hg2+ in different real samples, including cucumber, fish, soil, and water samples, with excellent recoveries of 98.1–99.5%. [ABSTRACT FROM AUTHOR]

Abstract Owing to the high cost and unavailability of different analytical techniques, there is an urgent need to develop new techniques not only for detecting but also removing mercury ions in real samples. Thus, an optical chemical sensor based on the anchoring of phenanthraquinone monophenylthiosemicarbazone in a plasticized cellulose triacetate membrane was fabricated and applied to the recognition and removal of mercury ions from aqueous solutions. The synthesized optode was characterized by FT-IR, SEM, AFM, and thermal analysis. Several parameters, including the pH, temperature, contact time, washing solvent, and washing time, were optimized. Under optimal conditions, a promising optode film platform was utilized for sensing mercury ions, and the concentrations were calculated based on colorimetric analysis (Histogram, RGB) of digital images, visualization, and spectrophotometry. Also, an optical optode was used for complete adsorption of mercury ions from aqueous solutions. In addition, the regeneration of the synthesized optode was evaluated using 0.1 mol L− 1 nitric acid, which effectively removed all adsorbed mercury ions. The obtained data indicated good linearity in the sensing and adsorption of Hg2+ over a concentration range of 0.005–5000 µgL − 1 with a low limit of detection (LOD = 0.066 µgL− 1) and limit of quantification (LOQ, 0.22 µgL − 1 ). Furthermore, it showed good distinctions in the presence of coexisting ions, high stability (five months), good applicability, and reproducibility (RSD = 1.31%), making it a promising sensor for Hg2+ detection. On the other hand, the kinetic studies revealed that the pseudo-second-order was the best model for describing the adsorption behavior of mercury ions on the optode surface. Also, the thermodynamic parameters indicate spontaneous (ΔG0

This work outlines the development of a voltammetric method for a sensitive, rapid, and environmentally friendly determination of the antihypertensive sotalol (SOT) in several sample types employing the anodically pretreated boron‐doped diamond electrode. Cyclic voltammograms of SOT presented a well‐defined irreversible oxidation peak at 1.21 V (Ag/AgCl (3.0 mol L−1 KCl)) in Britton–Robinson buffer solution (pH 3.0). Figures of merits recommended by the validation guidelines were evaluated for the validation of the present method. Employing differential pulse voltammetry linearity of SOT was obtained in the concentration range of 0.39–4.22 μmol L−1 in 0.1 mol L−1 H2SO4 solution, with a limit of detection of 0.031 μmol L−1. The selectivity of the method was assessed against interferers and show relative standard deviation (RSD) values lower than 6 %. Recovery tests yielded percentages ranging from 93 % to 96 % in urine sample and from 100 % to 107 % in tap water sample. The proposed method was successfully applied in pharmaceutical, environmental, and biological samples offering a suitable green analytical chemistry profile. [ABSTRACT FROM AUTHOR]

Mercury (Hg2+) as environmental pollutant is a widespread concern due to its cytotoxic effect in humans and animals and needs to be monitored through cost effective methods based on naked-eye detection. Herein, in this study, we extracted and isolated the limonin (LMN) via a facile procedure and then employed it as capping agent for the synthesis of silver nanoparticles (LMN-AgNPs) as a first report. LMN-AgNPs were characterized through Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), Zeta Potential Analyzer (ZPA) and Fourier Transform Infrared (FTIR) spectroscopy. As-formed LMN-AgNPs were recognized as extremely selective and highly sensitive colorimetric sensor for Hg2+ with potential analytical application. The developed sensor showed an outstanding linear correlation with the concentration of Hg2+ in the range of 0.002 − 55 µM via a color change from deep yellow to transparent showing hypsochromic-hypochromic shift with the limit of detection (LOD) and the limit of quantification (LOQ) as low as 0.21 nM and 0.7 nM respectively. The sensor was further allied with smartphone for immediate and on-site quantification of Hg2+. The LOD and LOQ of 0.42 µM and 1.4 µM was true for smartphone based sensing in the range of 7.5–55 µM Hg2+. The detection of Hg2+ was not disrupted by the presence of other metals in either of mentioned cases. The practical applicability of the proposed Hg2+ sensor was tested using spectrophotometric and smartphone based approaches in human serum and urine as well as in tap water samples with acceptable ranges of recovery. As-developed sensor can work as a potential candidate for monitoring of Hg2+ pollution in diverse fields of studies. [ABSTRACT FROM AUTHOR]

Increasing the release of antibiotics in particular tetracycline in the environment is become one of the most concerns that threat human and animals' health. Regarding their low cost, sensitivity, portability, electrochemical sensors have received attention for tetracycline monitoring. With a nanostructure, diverse active functional sites, and good conductivity, green nanoparticles are considered now as an attractive material for sensors design. The objective of the present paper is then the design of electrochemical sensor functionalized with green nanoparticles based on gum Arabic for tetracycline detection. The green nanoparticles are synthesized by direct reduction of silver nanoparticle with gum Arabic polymer. The intrinsic properties of the obtained nanoparticles are examined using different techniques namely UV–Vis absorption (UV), X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric TGA. To follow up, the sensor modification as well as tetracycline detection, cyclic voltammetry (CV) and square wave voltammetry are carried out. Correlation between the different results have demonstrated good dispersion and homogeneity of green nanoparticles, with good applicability in electrochemical measurements. In fact, the sensor has demonstrated wide concentrations range from 0.1 to 1250 nM with a limit of detection in the order of 0.056 nM, lower than those reported in the literature. The selectivity test, investigated against a various interfering with similar structure to tetracycline, have proven a good discrimination between all molecules. In addition, the sensor was successfully applied to real samples, and the found recovery rates are ranging from 90.4% to 106.9%. The obtained results confirm that green nanoparticles based on gum Arabic could commercially be viable for next generation of electrochemical sensor for tetracycline detection, and also could be applied for the detection of the variety of pharmaceutical pollutants in the environment. [ABSTRACT FROM AUTHOR]

Oxidative stress is a trigger for many diseases and occurs with the unstable hypochlorite (ClO−), known as one of the reactive oxygen species (ROS) in organisms. Then, HOCI is acknowledged as an oxidizing species that eliminates a variety of environmental pollutants. Hence, the development of novel methodologies for the selective and precise identification of HOCl/ ClO− is considered to be of utmost importance. In this study, the design, characterization, and applications of a fluorene-based fluorescent probe (FHBP) dependent on the ESIPT mechanism with a "turn-on" response for the sensitive/selective determination of ClO− against other competing samples were reported. The experimental results indicated that the detection limit for ClO−could be quantitatively determined by the probe to be 8.2 × 10−7 M. The binding constant of the probe FHBP with ClO− was computed as 9.75 × 103 M−1. In addition, the response time of FHBP was appointed to be 30 s, indicating a rapid reaction with ClO−. It has also been demonstrated that this probe can be successfully used for the detection of ClO− on filter papers, TLC sheets, cotton swabs, and real samples. [ABSTRACT FROM AUTHOR]

A novel enzyme-free sensor, constructed on a glassy carbon electrode (GCE) and featuring 2-dimensional (2-D) nanoporous magnesium oxide nanosheets (MgO-NSs), has been fabricated to enable the highly sensitive and selective detection of hydrogen peroxide (H2O2). MgO-NSs were successfully synthesized through a single-step, non-hazardous, and cost-effective sugar-blowing technique. The microstructure, porosity, thermal stability, and morphology of MgO-NSs were analyzed under XRD, FT-IR, FESEM, HR-TEM, TGA, and BET surface area. The electrochemical properties of MgO-NSs modified glassy carbon electrode (GCE) (MgO-NSs/GCE) were probed toward H2O2 sensing using CV, DPV, EIS, and amperometry techniques at varying concentrations, pH of the solution, and different scan rates. The fabricated electrode displayed remarkable selectivity, high sensitivity, and a linear response toward H2O2 in a wide concentration range of 20 µM-1000 µM at neutral pH with 0.224 µM limit of detection (LOD) and 0.753 µM limit of quantification (LOQ). The proposed electrochemical sensor based on MgO-NSs/GCE demonstrates multiple advantages like exceptionally high sensitivity, high selectivity, great stability, reproducibility, and excellent response toward the detection of hydrogen peroxide in milk and mixed-fruit juice samples as compared to the reports available in the literature. [ABSTRACT FROM AUTHOR]

A Novel bioanalytical detector based on Poly(Diaquabis(1,10-phenanthroline copper (II) Iodide) (poly([Cu(H2O)2P2]I2)/GCE) has been fabricated by potentiodynamic polymerization of [Cu(H2O)2P2]I2. The synthesized complex and the fabricated electrodes showed a promising electrocatalytic behavior towards the electrooxidation of Trimethoprim (TPM). Based on the regression coefficient value of scan rate with peak current and square root of peak current, the oxidation of TMP at poly([Cu(H2O)2P2]I2)/GCE was dominated by diffusion. Under the optimized experimental conditions and square wave voltammetric parameters, the poly([Cu(H2O)2P2]I2)/GCE revealed very wide responses in the range of concentration of 500 nM–160 μM with a limit of detection of 3.91 nM and a Limit of quantification of 13.02 nM with the relative standard deviation below 1.75 %. The valuable applicability of the fabricated sensor for the determination of TMP in real samples, including cow's milk, blood serum, and human urine, was successfully investigated. The electroanalysis results from the spike recovery and interference study provided an excellent range of recovery with an error percent of below 3.0 % in the combination effect with the potential interferents. The sensor exhibited excellent reproducibility, sensitivity, long-term stability, high accuracy, and fast response. The developed bioanalytical sensor revealed the best application prospect for biomedicine and environmental monitoring activities.

A novel post-synthetic modification of magnetite@MIL-53(Fe)-NH2 core-shell nanocomposite was performed to extract ultra-trace amounts of Pd(II) ions from the real samples. To explore and optimise the effect of parameters on the preconcentration design of the experiment was employed. The highest removal efficiency in the adsorption step was obtained using the following condition: pH of sample, 6.5; adsorption time, 3.8 min; magnetite@MIL-53(Fe)-NH-PITC NPs amount, 20 mg. The highest extraction recovery (%) was achieved using 0.8 mL of 0.85 mol L−1 HCl as the desorbing solution; and by applying an elution time of 3.5 min. Afterwards, to study the equilibrium data, various adsorption isotherm models were explored. The data showed that the Langmuir model describes the adsorption process better than the other models. Eventually, the maximum adsorption capacity and model constant equal to 100 mg g−1 and 0.11 L mg−1, were obtained, respectively. Besides, the kinetic data were well fitted to the pseudo-second-order based on the highest correlation coefficient that was achieved. The limit of detection, the limit of quantification, and the linear range of the proposed method were 0.05 μg L−1, 0.2 μg L−1, and 0.2–100 μg L−1 (r2 = 0.9936), respectively. The precision was explored as relative standard deviation value at three concentration of 0.5, 10, 75 ng mL−1 (n = 3) that was 12.5%, 9.3% and 6.6%, respectively. Ultimately, the new magnetic adsorbent could be employed for extraction/quantification of ultra-trace amounts of Pd(II) ions in real samples and the relative recovery values were obtained in the range of 88–102%. [ABSTRACT FROM AUTHOR]

This study presents a new and rapid analytical high‐performance liquid chromatography coupled with a photodiode array detector method for determining nickel ion (Ni2+) complex with Schiff base (Z)‐1‐(thiophen‐2‐yl‐methyleneamino) propane‐2‐ol easily. The influence of pH, surfactant, and effect of mobile phase on the formation of the Ni‐(Z)‐1‐(thiophen‐2‐yl‐methyleneamino)propane‐2‐ol complex was studied and optimized. The results showed that the acidic condition (pH = 5) favors the complexation most. Triton X‐100 neutral surfactant was used for dissolving the Ni–complex synthesized. A mobile phase ratio of methanol:acetonitrile:water 70:20:10, v/v/v was taken as optimum. This approach allowed the analysis of Ni2+ ion with the limit of detection of 0.0349 ng/mL over the linear range of (0.1–250 ng/mL) and a relative standard deviation of < 2%. The developed method exhibited remarkable extraction recoveries for Ni2+ in various real water samples (tap water; 98.0%–99.8% and river water; 97.0%–98.7%) and alloys with recoveries of (nichrome; 85.2% and chromel; 88.4%). Moreover, this protocol was also applied for the quantitation of Ni2+ in real sewage samples at a concentration level of 0.256 ng/mL. The outcomes of the present work successfully revealed the apparent superiority of Schiff base (Z)‐1‐(thiophen‐2‐yl‐methyleneamino) propane‐2‐ol toward the practical removal of target Ni2+ under real‐world conditions. [ABSTRACT FROM AUTHOR]

Cymoxanil (CYM) is one of the most important fungicides for various vegetables and fruits. However, its routine detection is still expensive due to high‐cost equipment. In this context, the silver nanoparticle‐based colorimetric probe was synthesized using triazole‐N‐acetamide thiazole (TAT) derivative as a stabilizer. The triazole‐N‐ acetamide thiazole (TAT) derivative functionalized silver nanoparticles (TAT‐AgNPs) were used as a probe for selective, efficient, rapid and quantitative determination of CYM in tap and river water. The characterization of TAT‐AgNPs was accomplished through UV‐visible, Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Zetasizer analysis. Highly sensitive surface plasmonic resonance band at 400 nm indicated complete reduction of Ag+ by using 1 : 15 (v/v) (TAT: AgNO3). The limit of detection (LOD), which corresponds to signal‐to‐noise ratio 3, is 0.013 μmol L−1, showed a linear response as a function of CYM concentration from 1 to 100 μM. Furthermore, the probe shows good selectivity when exposed to a series of interfering pesticides. TAT‐AgNPs were also spiked with blood plasma and the effects of relevant interfering studies were evaluated. The nanosensor detects the CYM tap water and river water samples. It confirmed that nanosensor can detect CYM in biological and environmental samples. [ABSTRACT FROM AUTHOR]

One of the most important organic molecules is metol [4-(methylamino)-phenol sulfate], which finds extensive usage in various applications as a monochromatic material. People, plants, and animals are all affected by it, and it raises serious environmental concerns. Developing a straightforward, quick, affordable, sensitive, and hands-on technique for metol determination in water bodies is of the utmost importance in the current scenario. A low-cost fabrication strategy is presented in this work for the synthesis of a zinc oxide nanoplatelet (ZnO) embedded into boron-doped carbon nitride nanosheet materials (ZnO/2D-BCN) utilizing a high-performance electrochemical sensor. The quantitative and qualitative information about the nanostructure of ZnO/2D-BCN were systematically analyzed further by using standard spectroscopic techniques such as XPS, XRD, FT-IR, EDAX, and Raman spectroscopy. 2D-nonstructural was observed to have a nanoplatelet/nanosheet through FE-SEM and TEM. Furthermore, electrochemical sensors' performance was analyzed by using cyclic and differential pulsed voltammetry techniques. The fabricated ZnO/2D-BCN has peculiar intrinsic structural features, both connectivity and characteristic synergistic effect of B-dopants 2D-structure, which perturb mass transport with highly efficient electrochemical pathways. In addition, the electrochemical sensors of metol and its electrocatalytic mechanism were scrutinized further, which confirmed a fast electron transfer event. The as-prepared ZnO/2D-BCN exposed superior sensing conclusion through LOD (8.6 nM) in a wide-ranging linear 0.039–1617 (μM) as well as a remarkable sensitivity of 0.804 μA μM–1 cm–2. Additionally, other sensing parameters such as remarkable repeatability, electrodes' reproducibility, materials' stability, and a remarkable selectivity toward metol have been performed. Furthermore, the practical feasibility of as-made ZnO/2D-BCN/GCE has been inspected with biological and environment samples such as blood serum, human urine, river, pond, industry, and tap samples as a real sample, revealing excellent rational recovery outcomes. [ABSTRACT FROM AUTHOR]

AbstractMycotoxins are toxic compounds that are formed as secondary metabolites by some fungal species that contaminate crops during pre- and postharvest stages. Exposure to mycotoxins can lead to adverse health effects in humans, such as carcinogenicity, mutagenicity, and teratogenicity. Hence, there is a need to develop analytical methods for their determination in vegetable oils that possess high sensitivity and selectivity. In the current review (116 references), the recent developments, current challenges, and perspectives in sample preparation techniques and chromatographic determination are summarized. It is impressive that current sample preparation techniques such as dispersive liquid–liquid microextraction (DLLME), quick, easy, cheap, rugged, and safe method (QuEChERS) and solid phase extraction (SPE) have exhibited high extraction recoveries and minimal matrix effects. However, a few studies have reported signal suppression or enhancement. Regarding chromatographic techniques, high sensitivity and selectivity have been reported by liquid chromatography coupled to fluorescence detection, tandem mass spectrometry, or high-resolution mass spectrometry. Furthermore, current challenges and perspectives in this field are tentatively proposed. [ABSTRACT FROM AUTHOR]

The Green, delicate and rapid ultrasound-assisted ionic liquid-based dispersive liquid-liquid microextraction technique was developed to preconcentrate trace quantities of zirconium Zr(IV) ion in real samples prior to spectrophotometric detection. The proposed method uses (1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate) ionic liquid (IL) as an extraction solvent for Zr(IV) ions after the complexation with quinalizarin at pH 5.0. The effect of various analytical parameters has been investigated. The calibration graph was linear in the range of 2.0–400 µg L − 1 and the limit of detection was 0.6 µg L-1. The preconcentration factor was 100. Relative standard deviation (RSD%) at 200 µg L-1 of Zr(IV)for intra-day and inter-day precisionwere 2.0 and 2.7%, respectively (n = 10). Certified reference materialswere used to verify the accuracy.The proposed method was applied to preconcentrate and determine the content of Zr(IV) in real environmental (water, soil and plants) samples with satisfactory results. [ABSTRACT FROM AUTHOR]

In this study, a new reduced graphene oxide (rGO) has been synthesized via a facile and envi­ronmentally friendly process using Callicarpa maingayi leaf extract. A novel magnetic catalyst based on Fe3O4 nanoparticles-reduced graphene oxide&carbon nanotubes ((Fe3O4- -(rGO&CNT)) was prepared and characterized by hydrothermal method. The Fe3O4 nanoparticles with an average size of 25 to 40 nm were placed on carbon nanotubes and reduced graphene oxide sheets, while carbon nanotubes inserted between the reduced graphene oxide sheets effectively prevented their aggregation. The (Fe3O4-(rGO&CNT) composite has a large surface area and good electrocatalytic properties, suiting for the detection and determination of imatinib (IM) anticancer drug by voltammetry method. Under opti­mi­zed conditions, good linearity was achieved in the concentration range of 0.1 to 40 μmol L-1 and the limit of detection and sensitivity were 57 nmol L-1 and 3.365 μA L μmol-1, respectively. Furthermore, the fabricated sensor demonstrated acceptable reproducible behaviour and accuracy and a high level of stability during all electrochemical tests. In addition, the proposed method was applied for the detection of IM in biological samples and the recoveries were 94.0 to 98.5 %, with relative standard deviations of 2.1 to 4.4 %.

Herein, we present a novel biosensor based on nature-inspired poly(caffeic acid) (PCA) grafted to magnetite (Fe3O4) nanoparticles with glucose oxidase (GOx) from Aspergillus niger via adsorption technique. The biomolecular corona was applied to the fabrication of a biosensor system with a screen-printed electrode (SPE). The obtained results indicated the operation of the system at a low potential (0.1 V). Then, amperometric measurements were performed to optimize conditions like various pH and temperatures. The SPE/Fe3O4@PCA-GOx biosensor presented a linear range from 0.05 mM to 25.0 mM, with a sensitivity of 1198.0 μA mM−1 cm−2 and a limit of detection of 5.23 μM, which was compared to other biosensors presented in the literature. The proposed system was selective towards various interferents (maltose, saccharose, fructose, L-cysteine, uric acid, dopamine and ascorbic acid) and shows high recovery in relation to tests on real samples, up to 10 months of work stability. Moreover, the Fe3O4@PCA-GOx biomolecular corona has been characterized using various techniques such as Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Bradford assay. [ABSTRACT FROM AUTHOR]

Glyphosate (Glyp) is an organophosphorus herbicide, and its abuse causes potential harm to the environment and human health. Thus, the development of simple and portable methods for rapid and visual detection of glyphosate is of great importance. Herein, we successfully developed a new fluorescent probe L with dansyl fluorophore as a fluorescent dye and tetrapeptide (Ala-Ser-Arg-His-NH2) as a recognition group. According to the design, L exhibited a specific fluorescence quenching response to Cu2+ and formed an L-Cu2+ ensemble with a molecular ratio of 2:1, demonstrating a limit of detection (LOD) as low as 12.04 nM. Interestingly, the L-Cu2+ ensemble as a relay response probe exhibited a specific fluorescence "off–on" response to glyphosate without interference from other pesticides and anions based on the strong complexation of glyphosate and Cu2+. The LOD of the L-Cu2+ ensemble for glyphosate was calculated as 12.59 nM. Additionally, the results of three recovery experiments with real samples showed that L has good practicability and accuracy in detecting glyphosate. Test strips were also fabricated to achieve facile detection of glyphosate to demonstrate the practical application potential of the L-Cu2+ ensemble. The L-Cu2+ ensemble was integrated with a smartphone for semi-quantification of glyphosate in a field environment under a 365 nm UV lamp. [ABSTRACT FROM AUTHOR]

In this study, a bimetallic palladium–copper aerogel was synthesized and used for modification of a graphite paste electrode (Pd-Cu/GPE), allowing the sensitive determination of bisphenol A (BPA). Different techniques, such as SEM, TEM, XPS, and AFM, were used for characterization of the Pd-Cu aerogel. To elucidate the properties of the Pd-Cu/GPE, the electrochemistry methods such as differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy were used. DPV measurements were conducted in phosphate electrolyte and buffer solution (0.2 M PBS, pH 5) at a potential range from 0.4 to 0.9 V vs. Ag/AgCl. The DPVs peaks currents increased linearly with BPA concentrations in the 0.04–85 and 85–305 µM ranges, with a limit of detection of 20 nM. The modified electrode was successfully used in real samples to determine BPA, and the results were compared to the standard HPLC method. The results showed that the Pd-Cu/GPE had good selectivity, stability, and sensitivity for BPA determination. [ABSTRACT FROM AUTHOR]

A colorimetric anion sensor (E)-3-((2-((4-(4-Methoxyphenyl)thiophen-2- yl)methyl)hydrazono)methyl)-1 H-indole ATH was synthesised and confirmed by different spectroscopic methods, such as 1 H NMR, 13 C NMR, ESI-Mass and FT-IR spectroscopy. The ATH sensor revealed the spectral change and detection in the presence of fluoride ion over the other anions such as OH−, Cl−, AcO−, I−, HSO4−, NO3−, Br−, S2-, CN− & NO2−. Interestingly, sensor ATH exhibited highly selective fluoride ion detection with significant changes in the colour from light yellow to dark yellow in ACN and ACN: H2O (8:2, v/v) medium. The colorimetric sensor effectively responds to fluoride ion stimulation through deprotonation and (ICT) intramolecular charge transfer sensing mechanism. The fluoride sensing mechanism was confirmed by 1 H NMR titration and was supported by density functional theory (DFT) and electrochemical studies. In this study, the B–H plot calculates the stoichiometry and binding constant (Ka) of the host-guest complex and strong interaction between the probe ATH with fluoride ions forming a 1:2 binding ratio. Furthermore, the test strips based on the probe ATH were used to detect F- ions qualitatively and quantitatively in 100% aqueous solution. [ABSTRACT FROM AUTHOR]

In the field of contaminated site remediation, risk analyses can be carried out by the use of appropriate mathematical models, based on simplified hypotheses of real sites. The possibility to have shared and accurate analytical methods is an important challenge for both routine laboratories and supervisory institutions. Although official methods (e.g., APH2009) are already available, they are lacking in some aspects, such as applicability to all the different sampling and analysis media and ease of use in routine analysis. Here, we report our recent advances in the implementation of an empirical method for hydrocarbon speciation in an air matrix, previously developed by the authors and published in 2015. The validation results led to a coefficient of variation (CV%) between 10–15% for the hydrocarbon fractions investigated (C5-C8 aliphatic, C9-C12 aliphatic, C9-C10 aromatic and C11-C12 aromatic) and recovery of ≤20%, in agreement with the required characteristics for the analytical methods. Several real samples were analyzed by the proposed method and the results were compared to those obtained by the official approach. The comparison led to an average bias (that is, the difference between the results from the developed method and those from the conventional one) of about 10%, confirming that the innovative approach is robust, accurate and can be applied to all the analytical media used for air sampling, such as soil gas. [ABSTRACT FROM AUTHOR]

Novel photoluminescent carbon dots (CDs) were synthesized through a facile hydrothermal method using Hibiscus tea extract as a natural carbon source and boric acid as a boron source. The optical and physicochemical properties of the as-synthesized nitrogen- and boron-doped CDs (NB-CDs) were characterized using UV–Visible (UV–Vis), photoluminescence (PL) spectroscopy, Fourier-transform infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The as-synthesized NB-CDs showed spherical morphology of approximately 6.2 ± 0.5 nm with quantum yield (9.2%), high aqueous solubility, strong photo-stability, and excitation-dependent PL behavior. The obtained NB-CDs exhibited high stability over a wide pH range and high ionic strength. Additionally, NB-CDs exhibited PL enhancement response with excellent sensitivity toward multi-metal ions, including Ag+, Cd2+, and Cr3+ ions, with very low detection limits of 44.5, 164.4, and 54.6 nM, respectively, with a wide concentration range of 0–10 μM. Upon testing the cytotoxicity of the NB-CDs at a concentration of 20 μg/mL for 24 h, we found no obvious inhibition of cell viability. Therefore, the proposed sensor method can be successfully applied to detect Ag+, Cd2+, and Cr3+ ions in cell imaging as well as in real water environmental samples. [ABSTRACT FROM AUTHOR]

In the present study, the first electrochemical investigation of ceritinib, which is a small-molecule tyrosine kinase inhibitor used as a new generation targeted anticancer drug, was described. For this purpose, a commercially available boron-doped diamond electrode pretreated cathodically was used. Using cyclic voltammetry, ceritinib presented two pairs of oxidation/reduction peaks in aqueous solution. The electrode process is controlled by a mixed diffusion and adsorption mechanism. The effects of pH and nature of the supporting electrolyte in the absence and the presence of anionic surfactant, sodium dodecylsulfate (SDS), pre-concentration variables and other instrumental parameters were demonstrated on the current response of ceritinib. It was observed that the addition of 8 × 10−4 mol L−1 SDS to the ceritinib solution prepared in 0.1 mol L−1 HNO3 improved the sensitivity of the stripping voltammetric measurements. By applying square-wave adsorptive stripping voltammetry (after 30 s pre-concentration at open-circuit condition), the calibration curves were linear for both oxidation peaks, Ia (at ~ + 0.99 V) and IIa (at ~ + 1.20 V) in the concentration range from 0.075 to 2.0 µg mL−1 (1.34 × 10−7–3.58 × 10−6 mol L−1), with detection limits of 0.014 µg mL−1 (2.50 × 10−8 mol L−1) for Ia, and 0.011 µg mL−1 (1.97 × 10−8 mol L−1) for IIa. The applicability of the developed methodology using the electrochemical signal IIa was verified by analysis of commercial capsule formulations and model human urine samples. [ABSTRACT FROM AUTHOR]

The production of heavy-metal pollutants in industrialized systems contributes to a variety of hazards, including threats to both the environment and human health. Of particular concern is the release of Cr(VI) wastewater, which can be toxic and potentially carcinogenic. As a result, the capture/removal and accurate detection of Cr(VI) was extremely critical. However, there were few efficient colorimetric methods available for the detection of Cr(VI). To address this issue, we have developed a simple and convenient method utilizing the Cu bimetal-organic framework (Cu-MOF) to construct a visual colorimetric sensor specifically designed for Cr(VI) detection. The synergism effect of -SH and -NH2 on the surface of Cu-MOF allows for the reduction of Cr(VI) to Cr(III). Meanwhile, oxidase substrate 3, 3', 5, 5'-tetramethylbenzidine (TMB) is converted to oxTMB, rapidly turning the colorless solution into deep blue. This strategy allows for the detection of Cr(VI) with a wide linear range of 0.2–100 μM within 1 min. Additionally, the limits of detection (LOD) were determined to be 0.023 μM. This method showed excellent selectivity in against potentially interfering metal ions and anions that commonly found in wastewater. Furthermore, with its fast response time and potential for on-site screening and point-of-care testing, the Cu-MOF sensor represents a promising development in the detection of Cr(VI). [ABSTRACT FROM AUTHOR]

In this paper, three benzothiazole‐Schiff bases, 2‐([benzothiazol‐2‐ylimino]methyl)phenol (L1), 2‐([benzothiazol‐2‐ylimino]methyl)‐4‐chlorophenol (L2), and 2‐([benzothiazol‐2‐ylimino]methyl)‐4‐bromophenol (L3), were environmentally friendly prepared using a microwave assisted synthesis. These synthesized ligands were used to chelate Cd (II) to produce three nano‐sized solid complexes, which were characterized using TEM, FT‐IR, and XRD. Then three developed spectrophotometric approaches for ultra‐trace quantification of divalent cadmium have been investigated and the sensitivity of these developed methods was enhanced using micellar medium. The influence of the type and amount of buffer, pH, type of surfactant, and amount of ligand during quantification of cadmium ion were monitored and determined. The calibration curve was valid over the concentration ranges of 1.0–9.0, 1.1–12.0, and 1.5–14.9 μg mL−1 of Cd (II) with detection limits of 0.407, 0.313, and 0.453 μg mL−1 using L1, L2, and L3, respectively. The described approaches had been effectively applied for Cd (II) ion quantification in some water samples. [ABSTRACT FROM AUTHOR]

A facile fluorescent probe (FFP) based on single-excitation/dual-emission detection system for the simultaneous sensing of fluoroquinolones (FQs) and copper was prepared via sol–gel polymerization using graphene carbon dots (GCDs) and CdTe quantum dots (CdTe QDs) as fluorescent units. FQs were detected by GCDs fluorescence enhancement, and copper (II) [Cu(II)] was detected by fluorescence quenching of the CdTe QDs in the FFP. If only one FQ co-existed with Cu(II), simultaneous quantitative analysis could be performed. The norfloxacin (NOR) was used as an example to investigate the working conditions of FFP. Under optimal conditions, the FFP could linearly recognize NOR with its concentration over the range 0–50 µM, with a detection limit of 1.6 nM. Meantime, the FFP could linearly detect the concentration of copper over the range of 0–10 µM, with a detection limit of 48.4 nM. NOR and Cu(II) were then detected simultaneously in tap water, drinking water, seawater, and milk with good recoveries. When multiple FQs co-existed with Cu(II), the FFP could discriminate among four different FQs via linear discriminant analysis. Therefore, this facile fluorescent probe can be used for simultaneous detection of various types of compounds in liquid samples. [ABSTRACT FROM AUTHOR]

Till to date, the application of sulfur-doped graphitic carbon nitride supported transition metal carbide interface for electrochemical sensor fabrication was less explored. In this work, we designed a simple synthesis of molybdenum carbide sphere embedded sulfur doped graphitic carbon nitride (Mo2C/SCN) catalyst for the nanomolar electrochemical sensor application. The synthesized Mo2C/SCN nanocatalyst was systematically characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with elemental mapping. The SEM images show that the porous SCN network adhered uniformly on Mo2C, causing a loss of crystallinity in the diffractogram. The corresponding elemental mapping of Mo2C/SCN shows distinct peaks for carbon (41.47%), nitrogen (32.54%), sulfur (1.37%), and molybdenum (24.62%) with no additional impurity peaks, reflecting the successful synthesis. Later, the glassy carbon electrode (GCE) was modified by Mo2C/SCN nanocatalyst for simultaneous sensing of uric acid (UA) and folic acid (FA). The fabricated Mo2C/SCN/GCE is capable of simultaneous and interference free electrochemical detection of UA and FA in a binary mixture. The limit of detection (LOD) calculated at Mo2C/SCN/GCE for UA and FA was 21.5 nM (0.09 – 47.0 μM) and 14.7 nM (0.09 – 167.25 μM) respectively by differential pulse voltammetric (DPV) technique. The presence of interferons has no significant effect on the sensor’s performance, making it suitable for real sample analysis. The present method can be extended to fabricate an electrochemical sensor for various molecules.

A novel nanoprobe based on S,O-doped carbon nitride quantum dots (S,O-CNQDs) was designed and synthesized. The as-prepared S,O-CNQDs exhibits good biocompatibility and strong fluorescence at excitation 360 nm. It is found that folic acid (FA) could efficiently quench the fluorescence of S,O-CNQDs. The obtained S,O-CNQDs is capable of acting as a sensitive and selective probe for FA detection in the range 5.0–83.3 μM with a detection limit of 90 nM. The as-prepared probe has been successfully utilized for the detection of FA in various real samples with satisfactory recoveries (98.8–107 %) and small relative standard deviation (

The electrochemical properties of ibrutinib (IBR), a new generation smart anti‐cancer drug, one of the Bruton's tyrosine kinase (BTK) inhibitors were investigated by a voltammetric method in the anionic surfactant (sodium dodecyl sulfate, SDS) medium with the boron‐doped diamond electrode (BDDE). IBR showed an oxidation step at about +1.56 V (vs Ag/AgCl (3.0 mol L−1 KCl) by cyclic voltammetry (CV) technique in 0.1 mol L−1 H2SO4 solution. IBR was found to be irreversible and diffusion‐controlled on the surface of the BDDE with studies of scan rate. The possible electrochemical oxidation reaction of IBR with the electroactive ring (pyrazole‐pyrimidine ring) in the structure of IBR is discussed. Square wave voltammetry (SWV) was preferred as the study method due to reproducibility for the determination of IBR in pharmaceutical and urine samples. At optimal values of SWV parameters, IBR showed good linearity in the concentration range of 0.01–2.00 μg mL−1 (5.7×10−8–2.3×10−6 mol L−1) in 0.1 mol L−1 H2SO4 with 6×10−4 M SDS. The detection (LOD) and quantification (LOQ) limits for IBR were set at 0.003 μg mL−1 (6.9×10−9 mol L−1) and 0.01 μg mL−1 (2.27×10−8 mol L−1), respectively. The relative standard deviation of the intra‐day and inter‐day repeatability of the proposed method was found 2.15 and 3.76, respectively. The necessary validation parameters have also been studied, and the recovery results obtained from both pharmaceutical dosage form and human urine samples show that the developed method is accurate and precise. [ABSTRACT FROM AUTHOR]

A simple electrochemical sensor based on electrochemically synthesized Fe3O4 nanoparticles was constructed by an ink with the nanoparticles, isopropanol, NAFION and carbon Vulcan to detect dopamine, uric acid and ascorbic acid. The electrocatalytic activity of the nanoparticles for the oxidation of the analyte molecules was examined by means of cyclic voltammetry and square wave voltammetry. The parameters controlling the performance of the sensor were optimized, such as the amount of Fe3O4 nanoparticles (1, 2, 3, 5, 8, 10 mg), amount of binder (5, 10, 15 µL) and carbon Vulcan in the ink (4, 6, 8 mg). The temperature was maintained at 25 °C and the pH was 7.5 with buffer phosphate. The optimal sensor conditions were 8 mg magnetite, 4 mg carbon Vulcan and 5 µL of NAFION@ 117. The calibration curves for the three analytes were determined separately, obtaining linear ranges of 10–100, 20–160 and 1050–2300 µM and limits of detection of 4.5, 14 and 95 µM for dopamine, uric acid and ascorbic acid, respectively. This electrochemical sensor has also shown significant sensitivity and selectivity without interference from the three analyte molecules presented simultaneously in solution. This sensor was applied for the detection of these molecules in real samples. [ABSTRACT FROM AUTHOR]

The determination of target analytes at very low concentrations is important for various fields such as the pharmaceutical industry, environmental protection, and the food industry. Caffeine, as a natural alkaloid, is widely consumed in various beverages and medicines. Apart from the beneficial effects for which it is used, caffeine also has negative effects, and for these reasons it is very important to determine its concentration in different mediums. Among numerous analytical techniques, electrochemical methods with appropriate sensors occupy a special place since they are efficient, fast, and entail relatively easy preparation and measurements. Electrochemical sensors based on carbon materials are very common in this type of research because they are cost-effective, have a wide potential range, and possess relative electrochemical inertness and electrocatalytic activity in various redox reactions. Additionally, these types of sensors could be modified to improve their analytical performances. The data available in the literature on the development and modification of electrochemical sensors for the determination of caffeine are summarized and discussed in this review. [ABSTRACT FROM AUTHOR]

Malondialdehyde (MDA), one of the most important products of lipid peroxidation, has been widely accepted as a biomarker to indicate food rancidity as well as the progress of some human diseases. However, ready detection of MDA with ultra-high sensitivity remains a challenge. In this work, a microfluidic surface-enhanced Raman scattering (SERS) sensing chip based on phosphoric acid induced nanoparticles aggregation was proposed for ultrasensitive MDA detection. The sensing chip was composed of an ultrafast microfluidic mixer, which efficiently transferred analytes to hot spots via the mixer assisted hot spots occupying (MAHSO) SERS strategy. Phosphoric acid, a reagent used in MDA detection, played the role of aggregator to induce aggregation of silver nanoparticles (Ag NPs); meanwhile, as fast as a few milliseconds mixing time effectively prevented over-aggregation of Ag NPs. Therefore, this process generated a uniform and dense SERS substrate with analyte molecules located in hot spots. As a result, the MDA SERS sensing chip possessed a limit of detection (LOD) lower than 3.3 × 10−11 M, high spot-to-spot uniformity with a relative standard deviation (RSD) of 9.0% and an excellent batch-to-batch reproducibility with a RSD of 3.9%. This method also demonstrated excellent specificity and reliability in real sample detection with recoveries of 90.4–109.8% in spiked tests. [ABSTRACT FROM AUTHOR]

[Display omitted] • The AIE fluorescent probe (NYVB) could detect Cys in multi-applications. • The test strips loaded with probe NYVB realized the visual detection of Cys. • Cys levels was observed under heavy metal-induced oxidative stress. Heavy metal ions tend to accumulate through the food chain and may cause many serious diseases. As an antioxidant, cysteine (Cys) plays a crucial role in regulating redox homeostasis. In addition, Cys is also widely used in the food industry. Therefore, the development of a convenient, sensitive, and practical tool for detecting Cys is of great significance for investigating the physiological and pathological functions of Cys induced by heavy metal ions. In this paper, a fluorescent probe NYVB with aggregation-induced emission (AIE) activities has been designed and synthesized, which featured good advantages in Cys detection, including favorable selectivity, desirable sensitivity, wide linear range, and low detection limit. The prepared solid-state sensor enabled the ratiometric visual detection of Cys. Probe NYVB has been successfully implemented for testing Cys in real food samples and serum samples with satisfactory recoveries. In addition, probe NYVB has been successfully employed for detecting endogenous and exogenous Cys in SKOV3 cells. More excitingly, probe NYVB has also been used to track the detection of Cys in H 2 O 2 , Hg2+, or Cu2+-induced redox imbalance. Overall, probe NYVB will open up a new avenue for studying Cys in the amelioration of heavy metal toxicity and has practical applications. [ABSTRACT FROM AUTHOR]

Here, a brand-new fluorescence BPGQD/g-C3N4 nanocomposite for measuring Vitamin B 12 has been created. The technique is based on the interaction between Vitamin B 12 and graphitic nitride nanosheets modified with graphene quantum dots co-doped with boron and phosphorus. The developed nanocomposites have been characterized by using various techniques such as HR-TEM, SEM, EDS, XRD, FT-IR, XPS, Photoluminescence and UV–Vis absorption spectroscopy. Different excitation wavelengths were used, with a 320 nm excitation wavelength and a 416 nm emission wavelength chosen for fluorometric detection. It examined how several factors, including the sample solution's pH, the length of the incubation period, and the impact of NaCl concentration, affected the intensity of the fluorescence. A linear standardization curve was validated in the Vitamin B12 range of 0–60 nM under the authorized conditions. The limit of detection (LOD) and limit of quantitation (LOQ) were 9.61 nM and 29.12 nM respectively. Using newly created nanocomposites, an RGB-based sensor for Vitamin B 12 detection was also constructed. Using this probe, it was possible to determine the amount of Vitamin B12 in human urine samples with respectable outcomes and satisfactory recoveries. [Display omitted] • Vitamin B 12 is necessary vitamins for human nutrition. • Novel Boron, phosphorus co-dopedGQDs/graphitic nitride based nanocomposites synthesized for detection of Vitamin B 12. • The Fluorescence based sensor showed low cost, short time, high sensitivity and selectivity. • Fluorescent based sensor achieved lowest LODs of 9.61 nM within a linear range of 0–60 nM. • RGB based sensor also developed for detection of vitamin B12 with LODs of 28.22 μM within a linear range of 0–100 μM. [ABSTRACT FROM AUTHOR]

Hypochlorous acid (HClO), as an oxidizing agent, is widely used in disinfection and sterilization in daily life. However, exposure to high concentrations of HClO is toxic to humans and animals. Therefore, it is important to realize efficient real-time detection of HClO in the environment. Herein, a cellulose-based fluorescent probe EC-YB for real-time detection of HClO was synthesized by esterification reaction using ethyl cellulose as a carrier. The probe EC-YB showed a significant fluorescence enhancement response to HClO. The EC-YB can selectively detect HClO with high sensitivity, anti-interference ability, and large Stokes shift (120 nm), and the limit of detection for HClO was 4.9 × 10−7 M. In addition, the probe EC-YB was successfully used for the determination of HClO in the environment and food. Notably, in order to further expand the application scenario of probe EC-YB in HClO detection, we successfully prepared electrostatically spun fiber membrane P-YB by mixing probe EC-YB with polystyrene, and successfully used it for selective detection and confocal imaging of HClO. • EC-YB achieves sensitivity and selectivity detection of hypochlorous acid. • EC-YB has lower detection limits (4.9 × 10–7 M) and larger Stokes shift (120 nm). • EC-YB has been successfully used to detect HClO in real water and food samples. • EC-YB composite PS electrostatic spinning membrane enables easy detection of HClO. [ABSTRACT FROM AUTHOR]

The manifestation of endurance of platinum nanoparticles (PtNPs) on glassy carbon electrode (GCE) along with single-walled carbon nanotubes (SWNTs) for methotrexate (MTX) quantification utilizing square wave voltammetry has been demonstrated. The fabricated sensor exhibits a negative shift in peak potential with amelioration in the peak current when compared to GCEs deposited solely with PtNPs or coated with SWNTs. A linear dynamic concentration range of 1–800 nM, is attained with an excellent sensitivity of 79.5 μA μM−1. Under optimized conditions, the proposed method exhibits 0.11 nM as the lowest limit of detection among all electrochemical investigations of MTX till date. The impact of typical physiological interferents on the current signal of the analyte was investigated. The potential application of the fabricated sensor was authenticated by the successful determination of MTX in patient urine samples for the first time. The developed electrochemical sensor was employed to test the presence of MTX in drug formulations, showcasing its potential utility in future biomedical and clinical diagnostic tools. Furthermore, a comparison between the findings of the proposed method and high performance liquid chromatography demonstrates a notable concordance, indicating consistency between both the approaches. [Display omitted] • Pt/SWNTs/GCE sensor was utilized for detection of methotrexate for the first time. • Remarkable analytical parameters with highest sensitivity and lowest detection limit. • Efficacious quantitation in pharmaceuticals, healthy human urine and serum samples. • Selective detection in real patient samples undergoing methotrexate treatment. • The developed sensor functions as a reliable diagnostic tool for drug analysis. [ABSTRACT FROM AUTHOR]

Early and precise diagnosis can prevent the severe effects of cancer, which is one of the leading health problems worldwide. Electrochemical (bio)sensors are at the forefront of technologies for this purpose due to their capacity to rapidly screen biomarkers, which is crucial for cancer diagnosis and health status monitoring. With the advantages of electrochemical analysis and nanomaterials' improved structural/chemical features, electrochemical biosensors offer outstanding performance for specific biomarker detection. Among different nanomaterials, silica-based nanomaterials contribute to developing enhanced (multi)functional sensing platforms. This review discusses the applications of electrochemical biosensors based on mesoporous silica nanomaterials for determining cancer biomarkers in biological fluids. Silica nanomaterials' types, synthesis methods, and properties are discussed comparatively. The current uses and developments of electrochemical biosensors and their functions in the last fifteen years are presented for practical applications in cancer biomarkers detection and monitoring to end with some concluding remarks, perspectives, and trends. • We review the applications of electrochemical cancer biomarker biosensors based on mesoporous silica nanomaterials. • We particularly focused on the determination of cancer biomarkers in biological fluids. • The types of the materials, synthesis methods, and properties are discussed. • Current uses and developments in this field are presented. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel EDTA/C-MIL-101-based electrochemical sensor was developed. • The as-prepared sensor was used for the simultaneous detection of heavy metal ions. • The sensor exhibited high electrochemical responses toward Cd2+, Pb2+, and Cu2+. • Stability and reusability of the sensor were checked for 20 uninterrupted measurements. • The applicability of the sensor was assessed to detect ions in lettuce extract. As heavy metal ions severely harm human health at certain threshold concentrations, there is a critical need to develop sensitive and selective techniques for their electrochemical sensing in the environment and food samples. Thus, a smart artificial electrochemical platform was fabricated for the detection of Cd2+, Pb2+, and Cu2+ in different real samples, including vegetables (e.g., lettuce), soil, and tap water samples. It is worth mentioning that the sensitivity of the sensor was enhanced using metal–organic framework (Fe-MIL-101). Consequently, ethylenediaminetetraacetic acid (EDTA), a nitrogen-rich carbon source and chelating agent, was immobilized into the pores of the Fe-MIL-101 by facile method. Using the hydrothermal technique, MIL-101 was partially calcined at 350 °C under nitrogen to obtain highly conductive Fe 2 O 3 doped carbon. The synergistic covalent coupling between the chelating agent, electrocatalytic active Fe 2 O 3 , and the high surface area of the carbonaceous platform effectively enhanced the sensing of the proposed metal ions. Under optimum conditions, the EDTA/C-MIl-101 (1:1) sensor exhibited superior electrochemical responses toward metal ions in the linear range from 1 μM to 100 μM with low limits of detection. Also, the proposed sensing platform can simultaneously detect these elements without any interference between their electrochemical signals, with permanent stability and good repeatability. The applicability of the fabricated materials was assessed to detect the proposed ions in different real samples, with satisfactory results (95.5–102 %). [ABSTRACT FROM AUTHOR]

Herein, we present a novel biosensor based on nature-inspired poly(caffeic acid) (PCA) grafted to magnetite (Fe3O4) nanoparticles with glucose oxidase (GOx) from Aspergillus niger via adsorption technique. The biomolecular corona was applied to the fabrication of a biosensor system with a screen-printed electrode (SPE). The obtained results indicated the operation of the system at a low potential (0.1 V). Then, amperometric measurements were performed to optimize conditions like various pH and temperatures. The SPE/Fe3O4@PCA-GOx biosensor presented a linear range from 0.05 mM to 25.0 mM, with a sensitivity of 1198.0 μA mM−1 cm−2 and a limit of detection of 5.23 μM, which was compared to other biosensors presented in the literature. The proposed system was selective towards various interferents (maltose, saccharose, fructose, L-cysteine, uric acid, dopamine and ascorbic acid) and shows high recovery in relation to tests on real samples, up to 10 months of work stability. Moreover, the Fe3O4@PCA-GOx biomolecular corona has been characterized using various techniques such as Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Bradford assay.

In the field of contaminated site remediation, risk analyses can be carried out by the use of appropriate mathematical models, based on simplified hypotheses of real sites. The possibility to have shared and accurate analytical methods is an important challenge for both routine laboratories and supervisory institutions. Although official methods (e.g., APH2009) are already available, they are lacking in some aspects, such as applicability to all the different sampling and analysis media and ease of use in routine analysis. Here, we report our recent advances in the implementation of an empirical method for hydrocarbon speciation in an air matrix, previously developed by the authors and published in 2015. The validation results led to a coefficient of variation (CV%) between 10–15% for the hydrocarbon fractions investigated (C5-C8 aliphatic, C9-C12 aliphatic, C9-C10 aromatic and C11-C12 aromatic) and recovery of ≤20%, in agreement with the required characteristics for the analytical methods. Several real samples were analyzed by the proposed method and the results were compared to those obtained by the official approach. The comparison led to an average bias (that is, the difference between the results from the developed method and those from the conventional one) of about 10%, confirming that the innovative approach is robust, accurate and can be applied to all the analytical media used for air sampling, such as soil gas.

In the present work, a simple ionothermal protocol for the synthesis of Au doped TiO2 and its subsequent application as an electrochemical interface for the trace level electroanalytical quantification of nitrite ion has been described. The surface morphology and the composition has been described with the help of Scanning electron microscope and Energy Dispersive X-Ray techniques. Further, it has been used in the fabrication of thin film electrodes by a simple physical drop casting method. Cyclic voltammetry has been used to decipher the electrocatalytic property of the modified interface towards nitrite ions and square wave voltammetry to work in the low concentration levels of nitrite ions. The developed sensor interface revealed superior nitrite sensing performance in the dynamic concentration range from 3.3 to 120 µM with a very low experimental detection limit of 0.095 µM with a sensitivity of 0.9973. The analytical applicability of the developed interference has been validated by determining the presence of nitrite from real samples with least interference from commonly encountered foreign ions. The stability and reproducibility of the proposed interface has been studied over a period of several months and the results were found to be highly reproducible with a relative standard deviation of ± 5 %. These results show that, the proposed interface electrode display better electrocatalytic activity compared to the previously reported sensors for the electro oxidation of nitrite ions.

Functional multiwall carbon nanotubes (f-MWCNTs) are of significant interest due to their dispersion ability in the aqueous phase and potential application in environmental, nanotechnology, and biological fields. Herein, we functionalized MWCNTs by a simple acid treatment under ultra-sonification, which represented a terminal or side-functional improvement for the fabrication of a toxic lead ion sensor. The f-MWCNTs were characterized in detail by XRD, Raman, XPS, BET, UV/vis, FTIR, and FESEM-coupled XEDS techniques. The analytical performance of the f-MWCNTs was studied for the selective detection of toxic lead ions by inductively coupled plasma-optical emission spectrometry (ICP-OES). The selectivity of the f-MWCNTs was evaluated using several metal ions such as Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Ni2+, Pb2+, and Zn2+ ions. Lastly, the newly designed ionic sensor was successfully employed to selectively detect lead ions in several environmental water samples with reasonable results. This approach introduced a new technique for the selective detection of heavy metal ions using functional carbon nanotubes with ICP-OES for the safety of environmental and healthcare fields on a broad scale. [ABSTRACT FROM AUTHOR]

In this study, we designed a point-of-care (POC) testing electrochemical biosensor using an integrated biosensing assay based on hollow-like nitrogen-doped carbon nanostructures combined with cobalt nanoparticles (Co@HNCNs, Co 3 O 4 @HNCNs, and CoP@HNCNs). These are functionalized with Anti-Exendin-4 Antibodies (Anti-Ex-4-Abs) and Bovine Serum Albumin (BSA) to create sensitive probes (Co@HNCNs/Anti-Ex-4-Abs/BSA, Co 3 O 4 @HNCNs/Anti-Ex-4-Abs/BSA, and CoP@HNCNs/Anti-Ex-4-Abs/BSA) for the ultrasensitive detection of exendin-4 (Ex-4), a peptide agonist used in the treatment of type 2 diabetes mellitus (T2DM). Among the cobalt-based carbon nanostructures, the Co 3 O 4 @HNCNs/Anti-Ex-4-Abs/BSA nanoprobe demonstrated superior ability to specifically recognize Ex-4. This was indicated by a significant decrease in the chronoamperometric (CA) i-t current response, facilitating low-level detection of Ex-4. The nanoprobe was capable of detecting Ex-4 concentrations ranging from 1.0 to 90.0 pM, with a sensitivity of 0.60 μA/pM and a limit of detection (LOD) of 0.46 pM (S/N = 3). Furthermore, the Co 3 O 4 @HNCNs/Anti-Ex-4-Abs/BSA nanoprobes demonstrated the ability to detect nanomolar levels of Ex-4 in blood serum and urine samples, achieving satisfactory recovery rates of 96-104%. The proposed electrostatic interaction chemistry approach establishes a remarkable platform for constructing a peptide agonist biosensor that is effective for detecting Ex-4 in real human serum and urine samples., 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 The Authors. Published by Elsevier B.V. All rights reserved.)

A simple, low-cost hydrothermal method was employed to synthesize highly fluorescent nitrogen-, fluorine-, and sulfur-co-doped carbon dots (NFS-CDs) using flufenamic acid and L-cysteine as precursors. The synthesized NFS-CDs exhibited dual emission peaks at 490 and 580 nm with a quantum yield of 24.7 %. They exhibit excellent stability, excitation-dependent fluorescent, and particle sizes ranging from 2 to 8 nm. The fluorescent chemosensor probe, NFS-CDs, showed strong selectivity and sensitivity for Hg 2+ over other metal ions investigated in aqueous solutions (pH ∼ 7.4). Strong fluorescent enhancement at 490 nm and considerable quenching at 580 nm was observed in the presence of Hg 2+ ions. The stoichiometric ratio of the NFS-CDs/Hg 2+ complex was optimized to 1:1 according to the Benesi-Hildebrand and Stern-Volmer plot methods. The NFS-CDs exhibited a linear dynamic detection range from 0 to 10 × 10 -6 M for Hg 2+ ions with a lower detection limit of 18.0 and 67.5 × 10 -9 M, respectively, at 490 and 580 nm. Practical applications of NFS-CDs in detecting Hg 2+ ions in natural water samples showed high recovery rates (98.9-104.6 %) and low relative standard deviation (RSD ≤ 2.47 %). The NFS-CDs/Hg 2+ achieved 78.7 ± 2.6 % and 83.4 ± 2.3 % antibacterial activity against E. coli and S. aureus as NFS-CDs/Hg 2+ could damage the bacterial walls when they entered the bacteria. Furthermore, the NFS-CDs were used to detect Hg 2+ ions intracellularly in HCT116 cells with low toxicity using live cell imaging., 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 Elsevier B.V. All rights reserved.)

A Novel bioanalytical detector based on Poly(Diaquabis(1,10-phenanthroline copper (II) Iodide) (poly([Cu(H 2 O) 2 P 2 ]I 2 )/GCE) has been fabricated by potentiodynamic polymerization of [Cu(H 2 O) 2 P 2 ]I 2 . The synthesized complex and the fabricated electrodes showed a promising electrocatalytic behavior towards the electrooxidation of Trimethoprim (TPM). Based on the regression coefficient value of scan rate with peak current and square root of peak current, the oxidation of TMP at poly([Cu(H 2 O) 2 P 2 ]I 2 )/GCE was dominated by diffusion. Under the optimized experimental conditions and square wave voltammetric parameters, the poly([Cu(H 2 O) 2 P 2 ]I 2 )/GCE revealed very wide responses in the range of concentration of 500 nM-160 μM with a limit of detection of 3.91 nM and a Limit of quantification of 13.02 nM with the relative standard deviation below 1.75 %. The valuable applicability of the fabricated sensor for the determination of TMP in real samples, including cow's milk, blood serum, and human urine, was successfully investigated. The electroanalysis results from the spike recovery and interference study provided an excellent range of recovery with an error percent of below 3.0 % in the combination effect with the potential interferents. The sensor exhibited excellent reproducibility, sensitivity, long-term stability, high accuracy, and fast response. The developed bioanalytical sensor revealed the best application prospect for biomedicine and environmental monitoring activities., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Melaku Metto reports equipment and supplies were provided by Bahir Dar University. Melaku Metto reports a relationship with Injibara University that includes: employment. There is no competing body for the current work that could conflict If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)

An easily synthesized reaction-based probe for the fluorescence detection of Hg 2+ ions using was reported. The designed probe exhibited "turn-on" fluorescence response towards Hg 2+ ions via deprotection of the thiocarbonate-protecting group to alcohol in the HEPES/EtOH=8:2 (v/v, 5 mM, pH 7.4). The investigation results of probe Bzp-1 properties for Hg 2+ detection indicated that probe Bzp-1 has satisfactory high selectivity and sensitivity. The detection limit of Bzp-1 for Hg 2+ was found to be 4.2 nM. The recognition mechanism of Bzp-1 for Hg 2+ was confirmed by ESI-MS. Moreover, the probe Bzp-1 has been successfully used to rapidly detect trace amounts of hazardous Hg 2+ ions in real samples such as tap water, seafood and soil with good recoveries and less the relative standard deviations. Moreover, the Bzp-1 can also be used for fluorescence imagining of Hg 2+ in living cells., 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.)

A new mononuclear Fe(II) complex with the formula [Fe(HL)2Cl2] (1) (HL= N-(2-hydroxy-1-naphthylidene)-2-methyl aniline) was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), UV–Vis and elemental analysis. The spectroscopy analyses revealed the two Schiff base ligands via oxygen and nitrogen atoms and two chloride atoms create an octahedral geometry. The nano-size of [Fe(HL)2Cl2] complex (2) was synthesized by the sonochemical process. Characterization of nano-complex (2) was carried out via X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-Vis, FT-IR spectroscopy. The nano-complex (2) average size synthesized via the sonochemical method was approximately 52 nm. In this work, a simple sensor based on a carbon paste electrode modified with [Fe(HL)2Cl2] nano-complex and the ionic liquid - IL (1-Butyl-3-methylimidazolium hexafluorophosphate) was developed ([Fe(HL)2Cl2] nano-complex-IL/CPE) for convenient and fast electrochemical detection of kojic acid. The modified electrode considerably improves voltammetric sensitivity toward kojic acid compared to the bare electrode. Experimental conditions influencing the analytical performance of the modified electrode were optimized. Under optimal conditions, the oxidation peak current was proportional to kojic acid concentration in the range from 0.3 to 237.0 μM with a detection limit of 0.09±0.001 μM. The [Fe(HL)2Cl2] nano-complex-IL/CPE sensor was successfully applied for the highly sensitive determination of kojic acid in real samples with satisfactory results.

The concept of color in chemistry can take us back to when the separation of color-based natural products, dyes, and other chemical compounds led to the technique called chromatography. The fundamental color-based chemical separation opened the modern ultra-speed, ultra-resolution chromatographic methods used for all analytical purposes in chemistry, biology, nanotechnology, and materials science today. The same color property of molecules either directly available or that can be created through indirect secondary chemical and biochemical reactions have led to the development of colorimetric sensors. More than ever before the need for user-friendly molecular diagnostics and on-site chemical analysis has been well recognized for their lifesaving roles in the pandemic era. The objective of this review article is to share some representative recent developments on colorimetric approaches for molecular diagnostics of relevance to viruses, food safety, disease diagnostics and management, and environmental analysis. Attention to the purpose of the sensor designs, rationale, and mechanistic aspects of the approaches are covered, and the demonstration of applicability for real sample analysis in each cited literature report is reviewed. Our scientific community should consider mandating sensor research reports to explicitly disclose the following key sensor attributes right in the abstract paragraph: (i) real sample evaluations, (ii) sample pretreatments, sample matrix dilutions, and their durations, (iii) differences in the analytical performance of isolated samples and complex real sample matrices, and (iv) robust independent validation/correlation methods to assess the fit-for-purpose of the sensor.