Determination of D&C Red 33 and Patent Blue V Azo dyes using an impressive electrochemical sensor based on carbon paste electrode modified with ZIF-8/g-C3N4/Co and ionic liquid in mouthwash and toothpaste as real samples

A bibliometric analysis of graphene in acetaminophen detection: Current status, development, and future directions

Acetaminophen is a widely used analgesic throughout the world. Detection of acetaminophen has particular value in pharmacy and clinics. Electrochemical sensors assembled with advanced materials are an effective method for the rapid detection of acetaminophen. Graphene-based carbon nanomaterials have been extensively investigated for potential analytical applications in the last decade. In this article, we selected papers containing both graphene and acetaminophen. Bibliometrics was used to analyze the relationships and trends among these papers. The results show that the topic has grown at a high rate since 2009. Among them, the detection of acetaminophen by an electrochemical sensor based on graphene is the most important direction. Graphene has moved from being a primary sensing material to a substrate for immobilization of other active ingredients. In addition, the degradation of acetaminophen using graphene-modified electrodes is also an important direction. We analyzed the research history and current status of this topic through bibliometrics. Authors, institutions, countries, and key literature were discussed. We also proposed perspectives for this topic.

Simple Preparation and Characterization of Hierarchical Flower-like NiCo2O4 Nanoplates: Applications for Sunset Yellow Electrochemical Analysis

The current work was performed to construct a novel electrochemical sensing system for determination of sunset yellow via the modification of screen-printed graphite electrode modified with hierarchical flower-like NiCo₂O₄ nanoplates (NiCo₂O₄/SPGE). The prepared material (hierarchical flower-like NiCo₂O₄ nanoplates) was analyzed by diverse microscopic and spectroscopic approaches for the crystallinity, composition, and morphology. Chronoamperometry, differential pulse voltammetry, linear sweep voltammetry, and cyclic voltammetry were used for determination of the electrochemical behavior of sunset yellow. The as-fabricated sensor had appreciable electro-catalytic performance and current sensitivity in detecting the sunset yellow. There were some advantages for NiCo₂O₄/SPGE under the optimized circumstances of sunset yellow determination, including a broad dynamic linear between 0.02 and 145.0 µM, high sensitivity of 0.67 μA/(μM.cm²), and a narrow limit of detection of 0.008 μM. The practical applicability of the proposed sensor was verified by determining the sunset yellow in real matrices, with satisfactory recoveries.

Electrochemical Sensor Based on Ni-Co Layered Double Hydroxide Hollow Nanostructures for Ultrasensitive Detection of Sumatriptan and Naproxen

In this work, Ni-Co layered double hydroxide (Ni-Co LDH) hollow nanostructures were synthesized and characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), and Fourier-transform infrared spectroscopy (FT-IR) techniques. A screen-printed electrode (SPE) surface was modified with as-fabricated Ni-Co LDHs to achieve a new sensing platform for determination of sumatriptan. The electrochemical behavior of the Ni-Co LDH-modified SPE (Ni-CO LDH/SPE) for sumatriptan determination was investigated using voltammetric methods. Compared with bare SPE, the presence of Ni-Co LDH was effective in the enhancement of electron transport rate between the electrode and analyte, as well as in the significant reduction of the overpotential of sumatriptan oxidation. Differential pulse voltammetry (DPV) was applied to perform a quantitative analysis of sumatriptan. The linearity range was found to be between 0.01 and 435.0 μM. The limits of detection (LOD) and sensitivity were 0.002 ± 0.0001 μM and 0.1017 ± 0.0001 μA/μM, respectively. In addition, the performance of the Ni-CO LDH/SPE for the determination of sumatriptan in the presence of naproxen was studied. Simultaneous analysis of sumatriptan with naproxen showed well-separated peaks leading to a quick and selective analysis of sumatriptan. Furthermore, the practical applicability of the prepared Ni-CO LDH/SPE sensor was examined in pharmaceutical and biological samples with satisfactory recovery results.

Simple turn-off fluorescence sensor for determination of raloxifene using gold nanoparticles stabilized by chitosan hydrogel

It is essential to develop a simple, applicable, and reliable assay to anticancer drug raloxifene (RAF) because of its significant usage and side effect due to entering residue in the environment. Fluorescence sensors developed and widely used because of them high selectivity, fast-response, and highly-sensitivity. The gold nanoparticles using chitosan hydrogel was synthesized and applied as a fluorescence sensor to determine the trace amount of RAF. The characterization methods including DLS, FE-SEM, EDX, XRD, and FT-IR were performed to confirm the synthesized structure. This sensor turned off the fluorescent signals proportional to RAF concentrations at 400 nm. The RAF can be detected in the linear range from 5 × 10^-7 to 5 × 10^-5 M. Limits of detection and quantification were obtained as 34 × 10^-8 and 11 × 10^-7 M as well as the relative standard deviation calculated as 1.63% in RAF measuring. The effective parameters on quenching efficiency were studied by central composite design (CCD) with response surface methodology (RSM). The effective parameters in RAF determination, include analyte concentration, temperature, contact time, and pH, were obtained as 35 μM, 30 °C, 8 min, and pH = 8.5. The sensor was applied to determine the RAF concentrations in biological and environmental samples with satisfactory recoveries between 97.5% and 109%.

Effect of grinding time on bismuth oxyhalides optical and morphological properties influence on photocatalytic removal of organic dye

Herein, we reported the synthesis of BiOX (X = Cl, Br) with different grinding time like 15 min and 30 min to analyze the evolution of physiochemical properties and the morphological evolution. The structural, optical, vibrational properties were examined by standard characterization studies. The formation of bismuth oxyhalides were confirmed by XRD and Raman studies. The crystallite size was decreased as in 30 min grinded sample whereas there is an influence of crystal structure. BiOCl (15 and 30 min) samples expelled the nanoflake like structure with the flakes arranged to form a nanoflower morphology. On comparing BiOCl (15 min), there is high orientation of nanoflakes on BiOCl (30 min) sample. As explored in BiOBr (15 and 30 min) samples, the development of nanoplates were found. The growth of nanoplates was enhanced in the better way in BiOBr (30 min) than BiOBr (15 min). The grinding time has explored a great influence on morphology. The photocatalyst test for prepared photocatalysts was performed to reduce the RhB dye. The photocatalysts showed 74%, 97%, 98% and 99.8% for BiOCl (15 min), BiOCl (30 min), BiOBr (15 min) and BiOBr (30 min). The rate constant value obtained was 0.008, 0.011, 0.021, 0.033 and 0.068 min^-1. BiOBr (30 min) sample achieved higher rate constant value. The hierarchical nanostructures and narrow bandgap has made the samples to be a potential candidate to reduce the toxic pollutants with complete efficiency.

A novel 2-dimensional nanocomposite as a mediator for the determination of doxorubicin in biological samples

In our study, the electrochemical properties of a novel activated nanocomposite were studied with 2-dimensional graphitic carbon nitride/sodium dodecyl sulfate/graphene nanoplatelets on the screen-printed electrodes (2D-g-C₃N₄/SDS/GNPs/SPE). The as-fabricated sensor exhibited excellent electrochemical performance, including wide dynamic ranges from 0.03 to 1.0 and 1.0-13.5 μM with a low limit of detection (LOD) of 10.0 nM. The fabricated 2D-g-C₃N₄/SDS/GNPs/SPE electrode exhibited high sensitivity, stability, good reproducibility, reusability, and repeatability towards DOX sensing. It can be utilized in real samples, including human plasma and urine, with excellent correlations and coefficients of variation below 6.0%. Therefore, this study presents potential application values in sensing DOX with efficient performance. Finally, the accuracy was attested by comparison with high-performance liquid chromatography (HPLC) as the reference method, signalizing a good agreement.

Lignosulfonate valorization into a Cu-containing magnetically recyclable photocatalyst for treating wastewater pollutants in aqueous media

This study presents an eco-friendly and economical process for preparing a magnetic copper complex conjugated to modified calcium lignosulfonate (LS) through a diamine (Fe₃O₄@LS@naphthalene-1,5-diamine@copper complex; FLN-Cu) as a green and novel catalyst. The prepared catalyst was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET), energy-dispersive X-ray spectroscopy (EDS), elemental mapping, inductively coupled plasma-optical emission spectrometry (ICP-OES) and field emission scanning electron microscopy (FESEM) techniques. The photocatalytic performance of the synthesized FLN-Cu catalyst was investigated by the degradation of aqueous solutions of dyes such as Rhodamine B (RhB), methylene blue (MB), and Congo red (CR) under UV irradiation. The dye degradation was followed by UV-Vis (ultraviolet-visible) spectrophotometry by measuring the changes in absorbance. The effects of different factors such as pH, contact time, photocatalyst dosage, and initial concentration of dye on the adsorption percentage were also investigated. Moreover, the catalyst showed high stability and could be readily separated from the reaction media using a magnet and reused five times without a remarkable loss of catalytic ability.

Survey of antibacterial activity and release kinetics of gold-decorated magnetic nanoparticles of Fe0 conjugated with sulfamethoxazole against Escherichia coli and Staphylococcus aureus

Drug delivery of antibiotics with magnetic nanoparticles improved by coating metals such as gold and silver has recently been studied. This work describe a simple method to synthesize modified magnetic nanoparticles which have high ability to modify the customary formulation of antibiotics such as sulfamethoxazole (SMX) and pursuant study of adsorption-desorption (release) of this drug. These synthesized nanoparticles were characterized by different methods, including field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and mapping, Fourier-transform infrared spectroscopy, X-ray diffraction, vibrating-sample magnetometry, thermogravimetric analysis and zeta potential test. Present assay showed a well correlation with the introduced carrier for the drug. Also the hypothesis were proved by some adsorption isotherm models and drug kinetics studies of carriers with different drug release kinetics models. This study confirmed the adsorption isotherm models and kinetics of drug sorbate are Temkin and Pseudo-First-Order Lagergren models, respectively; the kinetics of drug release from this carrier is based on Zero-Order model. The values of MIC in antibacterial test for pure SMX and SMX conjugated nanoparticles against Escherichia coli were calculated to be 14 and 2.5 μg/mL, respectively, and these values against Staphylococcus aureus were 24 and 1.25 μg/mL, respectively.

Recent advances in electrochemical sensor developments for detecting emerging pollutant in water environment

In the latest times, considerable studies have been performed closer to detecting emerging pollutant such as paracetamol in wastewater. Electrochemical sensor developments have recently started to determine in fewer concentrations effectively. The detection of paracetamol using standard protocols corresponding to electroanalytical techniques has a greater impact noticed in directing the detecting process toward biosensors. Non-enzymatic sensors are the peak of all electro analysis approaches. Functionalized materials, such as metal oxide nanoparticles, conducting polymers, and carbon-based materials for electrode surface functionalization have been used to create a fortification for distributing passive enzyme-free biosensors. Synergic effects are possible by enhancing loading capacity and mass transfer of reactants for attaining high analytical sensitivity using a variety of nanomaterials with large surface areas. The main focus of this study is to address the prevailing issues in the identification of paracetamol with the tasks in the non-enzymatic sensors field, followed by the useful methods of electro analysis studies.

Recent advances in electrochemical-based sensors amplified with carbon-based nanomaterials (CNMs) for sensing pharmaceutical and food pollutants

Foodborne-related infections due to additives and pollutants pose a considerable task for food processing enterprises. Therefore, the competent, cost-effective, and quick investigation of nutrition additives and contaminants is essential to reduce the threat of public fitness problems. The electrochemical sensor (ECS) shows facile and potent analytical approaches desirable for food protection and quality inspection over traditional methods. The consequence of a broad display of nanomaterials has paved the path for their relevance in designing high-performance ECSs appliances for medical diagnostics and conditions and food protection. This review article has discussed the importance of electrochemical-based sensors amplified with carbon-based nanomaterials (CNMs). Initially, we have demonstrated the types of pharmaceutical and food/agriculture pollutants (such as pesticides, heavy metals, antibiotics and other medical drugs) present in water. Subsequently, we have compiled the information on electrochemical techniques (such as voltammetric and electrochemical impedance spectroscopy) and their crucial parameters for detecting pollutants. Further, the applications of CNMs for sensing pharmaceutical and food pollutants have been demonstrated in detail. Finally, the topic has been concluded with existing challenges and future prospects.

Equilibrium and Kinetic Modeling of Crystal Violet Dye Adsorption by a Marine Diatom, Skeletonema costatum

Significant efforts have been made to improve adsorbents capable of eliminating pollutants from aqueous solutions, making it simple and quick to separate from the treated solution. In the current study, the removal of Crystal Violet Dye (CVD) from an aqueous synthetic solution onto a marine diatom alga, Skeletonema costatum, was investigated. Different experiments were conducted as a function of different pH, contact time, adsorbent dosage, temperature, and initial CVD concentration. The highest adsorption efficiency (98%) was obtained at 0.4 g of S. costatum, pH 3, and a contact time of 120 min, at 25 °C. Furthermore, Fourier-transform infrared spectroscopy (FTIR) results display that binding of CVD on S. costatum may occur by electrostatic and complexation reactions. Moreover, the Brunauer-Emmett-Teller surface area analysis (BET) obtained was 87.17 m2 g-1, which, in addition to a scanning electron microscope (SEM), reveals large pores that could enhance the uptake of large molecules. However, the equilibrium adsorption models were conducted by Halsey, Langmuir, Freundlich, Henderson, and Tempkin isotherm. In addition, multilayer adsorption isotherm best described the uptake of CVD onto S. costatum. The maximum monolayer adsorption capacity (qmax) was 6.410 mg g-1. Moreover, thermodynamic parameters of the adsorption studies suggested that the uptake of CVD onto S. costatum was endothermic and spontaneous. The pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetic equations were applied to model the adsorption kinetic data. It was seen that the kinetics of the adsorption may be described using pseudo-second-order kinetic equations. Finally, the present work concluded that the marine diatom alga S. costatum is suitable as a natural material for the adsorption of CVD.

Synthesis and characterization Agar/GO/ZnO NPs nanocomposite for removal of methylene blue and methyl orange as azo dyes from food industrial effluents

Herein, with using graphene oxide (GO), agar and ZnO NPs was synthesized as nanocomposite to removal of dyes contaminants from food industry effluents. Synthesis and characterization of the nanocomposite adsorbent were carried out by FTIR, XRD, FE-SEM, TEM, EDX and DLS analyses. The effects of various parameters such as pH, initial dye concentration, contact time and temperature on the removal of methylene blue (MB) and methyl orange (MO) as azo dyes were investigated. The used nanocomposite can be effective in the adsorption of dyes due to their different functional groups. The Freundlich and Langmuir models were used to investigate the isotherm of contaminants removal. The results showed that the removal of methylene blue and methyl orange dyes followed the Freundlich isotherm, and the values of the R² correlation coefficient for agar/GO, and agar/GO/ZnO nanocomposites for MB dye was 0.9640 and 0.9977, respectively, and for dye MO, 0.9918 and 0.9683, respectively. The maximum removal percentages for MB and MO dyes were 88% and 91%, respectively.

Cyclic and Linear Sweep Voltammetric Studies of a Modified Carbon Paste Electrode with Nickel Oxide Nanoparticles toward Tamoxifen: Effects of Surface Modification on Electrode Response Kinetics

Due to the serious adverse futures of some anticancer drugs, the determination of trace amounts of these drugs by simple analytical techniques is of great interest. In this regard, knowing about the mechanism of the analyte with the sensing material plays an important role. Nickel oxide nanoparticles (NiO NPs) modified by a carbon paste electrode (NiO-CPE) showed an irreversible cyclic voltammetric (CV) behavior in the NaOH (pH 13) supporting electrolyte based on the peak separation of 311 mV. Its peak current was decreased by adding tamoxifen (TAM), confirming that TAM molecules can consume NiO before participating in the electrode reaction. For this goal, TAM can be oxidized or reduced, and the corresponding mechanisms are schematically illustrated in the text. This study focused on the kinetic aspects of the process. Based on the CV results, a surface coverage (Γ) value of 2.72 × 10^-5 mol NiO per cm² was obtained with charge transfer coefficients α_a and α_c of 0.317 and 0.563, respectively. α_a and α_c values were changed to 0.08 and 0.72 in the presence of TAM. Further, the rate constant (k _s) value was 0.021 ± 0.01 s^-1 in the presence of TAM. In linear sweep voltammetry (LSV), an α value of about 0.636 ± 0.023 and an exchange rate constant (k _o) value of about 0.097 ± 0.031 s^-1 were obtained in the absence of TAM, which changed to 0.62 ± 0.081 and 0.089 ± 0.021 s^-1 in the presence of TAM, respectively. Despite more published papers, when the TAM analyte was added to the NaOH supporting electrolyte, both anodic and cathodic peak currents of the modified NiO-CPE decreased. We suggested some reasons for this decreased peak current, and four mechanisms were illustrated for the electrode response in the presence of TAM.

Nano-architectural design of TiO2 for high performance photocatalytic degradation of organic pollutant: A review

In the past several decades, significant efforts have been paid toward photocatalytic degradation of organic pollutants in environmental research. During the past years, titanium dioxide nano-architectures (TiO₂ NAs) have been widely used in water purification applications with photocatalytic degradation processes under Uv/Vis light illumination. Photocatalysis process with nano-architectural design of TiO₂ is viewed as an efficient procedure for directly channeling solar energy into water treatment reactions. The considerable band-gap values and the subsequent short life time of photo-generated charge carriers are showed among the limitations of this approach. One of these effective efforts is the using of oxidation processes with advance semiconductor photocatalyst NAs for degradation the organic pollutants under UV/Vis irradiation. Among them, nano-architectural design of TiO₂ photocatalyst (such as Janus, yolk-shell (Y@S), hollow microspheres (HMSs) and nano-belt) is an effective way to improve oxidation processes for increasing photocatalytic activity in water treatment applications. In the light of the above issues, this study tends to provide a critical overview of the used strategies for preparing TiO₂ photocatalysts with desirable physicochemical properties like enhanced absorption of light, low density, high surface area, photo-stability, and charge-carrier behavior. Among the various nanoarchitectural design of TiO₂, the Y@S and HMSs have created a great appeal given their considerable large surface area, low density, homogeneous catalytic environment, favorable light harvesting properties, and enhanced molecular diffusion kinetics of the particles. In this review was summarized the developments that have been made for nano-architectural design of TiO2 photocatalyst. Additional focus is placed on the realization of interfacial charge and the possibility of achieving charge carriers separation for these NAs as electron migration is the extremely important factor for increasing the photocatalytic activity.

Metal-organic framework-based materials for the abatement of air pollution and decontamination of wastewater

Developing new and efficient technologies for environmental remediation is becoming significant due to the increase in global concerns such as climate change, severe epidemics, and energy crises. Air pollution, primarily due to increased levels of H₂S, SO_x, NH₃, NO_x, CO, volatile organic compounds (VOC), and particulate matter (PM) in the atmosphere, has a significant impact on public health, and exhaust gases harm the natural sulfur, nitrogen, and carbon cycles. Similarly, wastewater discharged to the environment with metal ions, herbicides, pharmaceuticals, personal care products, dyes, and aromatics/organic compounds is a risk for health since it may lead to an outbreak of waterborne pathogens and increase the exposure to endocrine-disrupting agents. Therefore, developing new and efficient air and water quality management systems is critical. Metal-organic frameworks (MOFs) are novel materials for which the main application areas include gas storage and separation, water harvesting from the atmosphere, chemical sensing, power storage, drug delivery, and food preservation. Due to their versatile structural motifs that can be modified during synthesis, MOFs also have a great promise for green applications including air and water pollution remediation. The motivation to use MOFs for environmental applications prompted the modification of their structures via the addition of metal and functional groups, as well as the creation of heterostructures by mixing MOFs with other nanomaterials, to effectively remove hazardous contaminants from wastewater and the atmosphere. In this review, we focus on the state-of-the-art environmental applications of MOFs, particularly for water treatment and air pollution, by highlighting the groundbreaking studies in which MOFs have been used as adsorbents, membranes, and photocatalysts for the abatement of air and water pollution. We finally address the opportunities and challenges for the environmental applications of MOFs.

Fabrication of sensor based on polyvinyl alcohol functionalized tungsten oxide/reduced graphene oxide nanocomposite for electrochemical monitoring of 4-aminophenol

4-aminophenol (4-AP) is one of the major environmental pollutants which is broadly exploited as drug intermediate in the pharmaceutical formulations. The extensive release of 4-AP in the environment without treatment has become a serious issue that has led several health effects on humans. This work describe the determination of 4-AP through a new chemically modified sensor based on polyvinyl alcohol functionalized tungsten oxide/reduced graphene oxide (PVA/WO₃/rGO) nanocomposite. The fabricated nanocomposite was characterized through XRD and HR-TEM to confirm the crystalline structure with average size of 35.9 nm and 2D texture with ultra-fine sheets. The electrochemical characterization of fabricated sensor was carried out by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) to ensure the charge transfer kinetics of modified sensor that revealed high conductivity of PVA/WO₃/rGO/GCE. Under optimized conditions e.g. scan rate 80 mV/s, phosphate buffer (pH 6) as supporting electrolyte and potential window from -0.2 to 0.8 V, the prepared sensor showed excellent response for 4-AP. The linear dynamic range of developed method was optimized as 0.003-70 μM. The LOD of fabricated sensor based on PVA/WO₃/rGO/GCE for 4-AP was calculated as 0.51 nM. The practical application of PVA/WO₃/rGO/GCE was tested in real water and pharmaceutical samples. The fabricated sensor presented here, exhibited exceptional stability and sensitivity than the reported sensors and could be effectively used for the monitoring 4-AP without interferences.

Facile Synthesis of NiO/ZnO nanocomposite as an effective platform for electrochemical determination of carbamazepine

The pharmaceutical science demand for sustainable and selective electrochemical sensors which exhibit ultrasensitive capabilities for the monitoring of different drugs. In an attempt to build a useful electrochemical sensor, we describe a most efficient method for the fabrication of NiO/ZnO nanocomposite through aqueous chemical growth method. The successfully synthesized NiO/ZnO nanocomposite is successfully employed to modify a glassy carbon electrode in order to build a sensitive and reliable electrochemical sensor for the detection of carbamazepine (CBZ), an anticonvulsant drug. The morphological texture, functionalities and crystalline structure of prepared nanocomposite were determined via FTIR, XRD, EDX, TEM, and SEM analysis. In order to examine the charge transfer kinetics, the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to exploit the electrochemical properties of the synthesized nanocomposite. The NiO/ZnO nanocomposite exhibited excellent electron transfer kinetics and less resistive behavior than the individual NiO and ZnO nanoparticles. The differential pulse voltammetry and cyclic voltammetry tools were used for the fluent determination of CBZ. Certain parameters were optimized to develop an effective method including optimum scan rate 60 mV/s, potential range from 0.4 to 1.4 V and BRB as supporting electrolyte with pH 3. The developed sensor showed exceptional response for CBZ under the linear dynamic range from 5 to 100 μM. The limit of detection of proposed NiO/ZnO sensor for the CBZ was calculated to be 0.08 μM. The analytical approach of prepared electrochemical sensor was investigated in different pharmaceutical formulation with acceptable percent recoveries ranging from 96.7 to 98.6%.

Determination of active ingredients in antihypertensive drugs using a novel green HPLC method approach

A novel, sensitive, fast, and pratic RP-HPLC methods were presented for the quantitative amounts of Telmisartan (TEL) and Olmesartan (OLM) in the presence of Amlodipin (AML) in a binary mixture of pharmaceutical preparation. Waters Spherisorb ODS-2 C18 column was used for separation. These methods were valid over linearity ranges of 2.5-30 μμg/mlL, 2-85 μμg/mlL, and 2-35 μμg/mlL for OLM, TEL, and AML, respectively. The mobile phase system consisted of acetonitrile:methanol: phosphate buffer at pH 3.0 (65:5:30 v/v/v), and the flow rate was 1,5 mlL/min for OLM and AML. The mobile system's other mixture (TEL and AML) was acetonitrile:methanol: phosphate buffer at pH 2.5 (65:5:30 v/v/v), and the flow rate was 1,5 mlL/min. These procedures were successfully applied to bulk, laboratory synthetic mixture, and medicinal dosage forms to use active ingredients quantitatively. The studied methods were validated according to ICH guidelines. In the developed HPLC method, the limit of detection values was found to be 0.020 μμg/mlL for TEL, 0.025 μμg/mlL for OML, and 0.070 μμg/mlL for AML. The correlation coefficients for the HPLC method were found to be 0.9938 for TEL, 0.9996 for OML, and 0.9982 for AML. The calibration range is between 2.5 and -30, 5-35, and 2-85 μμg/mlL for OLM, AML, and TEL, respectively. The proposed HPLC method is a convenient, effective, sensitive, green, and time-saving method for the rapid determination of TEL and OLM in the presence of AML.

A modified carbon paste electrode with N-rGO/CuO nanocomposite and ionic liquid for the efficient and cheap voltammetric sensing of hydroquinone in water specimens

This paper reports a voltammetric sensor based on copper oxide nanoparticles on nitrogen-doped reduced graphene oxide nanocomposite (N-rGO/CuO)-ionic liquid modified carbon paste electrode (N-rGO/CuO-ILCPE) for determining the hydroquinone (HQ). The N-rGO/CuO was prepared by a facile protocol, followed by characterization via fourier transform-infrared (FT-IR) patterns, field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) analysis. The electrochemical behaviour was linearly symmetrical to various hydroquinone levels (1.0-600.0 μM) with a narrow limit of detection (LOD = 0.25 μM). The diffusion coefficient was also estimated to be 4.1 × 10^-6 cm²/s. The N-rGO/CuO-ILCPE was impressively applicable in determination of hydroquinone in the real specimens.

Self assembled three dimensional β-Cu2V2O7 hierarchical flower decorated porous carbon: An efficient electrocatalyst for flutamide detection in biological and environmental samples

The serious situation mandates the use of anticancer drugs, which protect people all over the world from the growth of prostate cancer. In particular, excessive dosage and erroneous discharge of flutamide concentration cause make environmental pollution on the surface of the wastewater. In this study, the highly sensitive and selective electrochemical approach based on copper vanadium oxide decorated porous carbon (denoted as β-Cu₂V₂O₇/PC) composite modified glassy carbon electrode (GCE) has been developed and it was applied for sensitive detection of anticancer drug flutamide (FTM). Moreover, using the co-precipitation method, the flower-like β-Cu₂V₂O₇ hierarchical microstructure was synthesized, and through the wet chemical process, the β-Cu₂V₂O₇/PC composite was obtained. The resultant product was characterized by XRD, FTIR, RAMAN, XPS and structural morphology established by FESEM analysis. Besides that, the electrochemical characterization and properties were analyzed by cyclic voltammetry (CV) and amperometric (i-t) techniques. The β-Cu₂V₂O₇/PC/RDGCE had two linear ranges at 0.01-2.11 μM and 2.31-30.81 μM. The lower limits of detection and sensitivity were found at 0.62 nM (S/N = 3), and 24.33 μA μM^-1 cm^-2 respectively. The practicability test was applied for the determination of FTM in urine, blood serum and environmental aquatic fluid with satisfactory recovery obtained.

Electrochemical detection of nicotine at a carbon Nanofiber-Poly(amidoamine) dendrimer modified glassy carbon electrode

Development of electrochemical sensors for important drugs such nicotine (an addictive drug) is important for the society. This study reports the electrochemical detection of nicotine at a carbon nanofiber/poly (amidoamine) dendrimer modified glassy carbon electrode. The carbon nanofiber (CNF) modified GCE was prepared by drop-coating followed by the electrodeposition of generation 4 poly (amidoamine) succinamic acid dendrimer (PAMAM) to form the sensor - CNF-PAMAM GCE. Characterization of prepared materials and modified electrodes was carried out using Fourier transmission infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The CNF-PAMAM composite was confirmed by microscopy. A marked reduction in charge transfer resistance and increase in current of the CNF-PAMAM GCE in comparison to the bare electrode showed a synergic improvement electrochemical response because of the CNF-PAMAM nanocomposite. The CNF-PAMAM demonstrated an enhanced performance in the oxidation of nicotine in comparison to the bare GCE by shifting the anodic potential E_pa of nicotine from 0.9 V to 0.8 V. The electrochemical sensor achieved a detection limit (LOD) of 0.02637 μM in the concentration range of 0.4815-15.41 μM of nicotine in 0.1 M PBS at pH 7.5. The sensor ability to determine nicotine in real samples was assessed in cigarettes obtaining recovery percentages of 88.00 and 97.42%. The sensor demonstrated selectivity toward nicotine in the presence of interferences. Finally, the method was validated by ultraviolet-visible spectroscopy analysis.

Fabrication and characterization of magnetic nanomaterials for the removal of toxic pollutants from water environment: A review

The success of any sustainable growth represents an advancement of novel approaches and new methodologies for managing any ecological concern. Magnetic nanoparticles have gained recent interest owing to their versatile properties such as controlled size, shape, quantum and surface effect, etc, and outcome in wastewater treatment and pollutant removal. Developments have progressed in synthesizing magnetic nanoparticles with the required size, shape and morphology, surface and chemical composition. Magnetic nanoparticles are target specific and inexpensive compared to conventional treatment techniques. This review insight into the synthesis of magnetic nanoparticles using physical, chemical, and biological methods. The biological method of synthesizing magnetic nanoparticles serves to be cost-effective, green process, and eco-friendly for various applications. Characterization studies of synthesized nanoparticles using TEM, XRD, SARS, SANS, DLS, etc are discussed in detail. Magnetic nanoparticles are widely utilized in recent research for removing organic and inorganic contaminants. It was found that the magnetic nanosorption approach together with redox reactions proves to be an effective and flexible mechanism for the removal of pollutants from waste effluents.

Electrochemical monitoring of bisphenol-s through nanostructured tin oxide/Nafion/GCE: A solution to environmental pollution

Over the past few decades, phenolic compounds have been broadly exploited in the industries to be utilized in several applications including polycarbonate plastic, food containers, epoxy resins, etc. One of the major compounds in phenolics is Bisphenol-S (BPS) which has dominantly replaced Bisphenol-A in several applications. Phenolic compounds are extensively drained into the environment without proper treatment and cause several health hazards. Thus, to tackle this serious problem an electrochemical sensor based on SnO₂/GCE has been successfully engineered to monitor the low-level concentration of BPS in water samples. The fabrication of SnO₂ nanoparticles (SnO₂ NPs) was confirmed through FTIR, XRD, and TEM to examine the size, crystallinity, internal texture, and functionalities of the prepared material. The fabricated material was exploited as a chemically modified sensor for the determination of BPS in water samples collected from different sources. Under optimal conditions such as scan sweep 100 mV/s, PBS electrolyte pH of 6, potential window (0.3-1.3 V), the proposed sensor manifested an excellent response for BPS. The LOD of the present method for BPS was calculated as 0.007 μM, respectively. Moreover, the stability and selectivity profile of SnO₂/GCE for BPS in the real matrix was examined to be outstanding.

Application of carbon nanotubes in sensing/monitoring of pancreas and liver cancer

Liver and pancreatic tumors are among the third leading causes of cancer-associated death worldwide. In addition to poor prognosis, both cancer types are diagnosed at advanced and metastatic stages without typical prior symptoms. Unfortunately, the existing theranostic approaches are inefficient in cancer diagnosis and treatment. Carbon nanotubes (CNTs) have attracted increasing attention in this context due to their distinct properties, including variable functionalization capability, biocompatibility, and excellent thermodynamic and optical features. As a consequence, they are now regarded as one of the most promising materials for this application. The current review aims to summarize and discuss the role of CNT in pancreatic and liver cancer theranostics. Accordingly, the breakthroughs achieved so far are classified based on the cancer type and analyzed in detail. The most feasible tactics utilizing CNT-based solutions for both cancer diagnosis and treatment are presented from the biomedical point of view. Finally, a future outlook is provided, which anticipates how the R&D community can build on the already developed methodologies and the subsequent biological responses of the pancreatic and liver cancer cells to the directed procedures.

A review on nanomaterial-based electrochemical sensors for determination of vanillin in food samples

Vanillin is an organic compound that not only acts as a flavoring and fragrance enhancer in some foods, but also can have antioxidant, anti-inflammatory, anti-cancer and anti-depressant effects. Nevertheless, its excessive use can be associated with side effects on human health. Consequently, there is a need to achieve a rapid vanillin determination approach to enhance food safety. The diversity and high sensitivity of analytical approaches has led researchers to use more advanced and efficient methods providing quantitative and qualitative outcomes in complex matrices. Among these, prominent attention has been drawn to electrochemical sensors for reasons such as reliability, simplicity, cost-effectiveness, portability, selectivity, and ease of operation, especially for the determination of vanillin. Nanomaterials are a good candidate for sensor construction due to their commendable physicochemical attributes. Some advanced nanostructures with promising platforms for high-sensitivity, highly selective, and long-lasting electrochemical sensors include graphene (Gr) and its derivatives, graphite carbon nitride (g-C₃N₄), carbon nanotubes (CNTs), metal nanoparticles, metal organic frameworks, carbon nanofibers (CNFs) and quantum dots. Study about sizes, dimensions, and morphologies of nanomaterials makes strong candidates for improving sensitivity or selectivity according to electrocatalytic abilities. The low LOD and wide linear range of samples demonstrated an excellent catalytic performance towards the vanillin oxidation. Some investigations have reported the synergistic effects like great conductivity of carbon nanomaterials which improved the electrocatalytic performance of nanocomposites which demonstrated the estimable sensitivity of nanomaterial-supported electrochemical sensors for determination of vanillin concentrations. The sensors which have reported have a commendable response to practical potential and evaluated in biscuit, pudding powder, chocolate, custard specimens and etc. sensitivity, stability, reproducibility and repeatability of suggested sensor were investigated. The present review article scrutinizes recent advances in the fabrication of nanomaterial-based electrochemical sensors to detect vanillin in various food matrices.

Eco-friendly, green synthesized copper oxide nanoparticle (CuNPs) from an important medicinal plant Turnera subulata Sm. and its biological evaluation

In this report, the green fabrication of copper oxide nanoparticles (CuNPs) using Turnera subulata leaf extract and assessed for the antibacterial and photocatalytic activities. The synthesis of CuNPs was performed using the leaves of T. subulata (TS-CuNPs) and characterized using UV-visible spectrophotometry, Fourier transforms infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX). Produced TS-CuNPs showing transmittance peaks approximately 707-878 cm^-1, with a spherical shape particle with an average size of 58.5 nm. As synthesized TS-CuNPs were used as a coating material in cotton fabrics and tested the efficacy against Gram-negative and Gram-positive bacterial pathogens. TS-CuNPs inhibited the growth of Escherichia coli and Staphylococcus aureus on cotton fabrics. Antibiofilm activity of TS-CuNPs showed a 4-fold reduction in the biofilm formation of E. coli and S. aureus. Structural morphology of TS-CuNPs coated on cotton fabric analysis using SEM-EDX confirmed the attachment of TS-CuNPs and reduction in the bacterial attachment to the cotton fabrics. Thus, this study provides a potential strategy to improve the antibacterial property of cotton fabrics in textile production for medical, sportswear, and casual wear applications. Further, the photocatalytic activity against the tested dyes evident the potential in dye industry wastewater treatment. Hence, this work represents a simple, greener, and cost-effective route for in situ synthesis of CuNPs with the potential antibacterial and as a dye degradation agent for water remediation.

An improved electrochemical sensor based on triton X-100 functionalized SnO2 nanoparticles for ultrasensitive determination of cadmium

The drastic increases in the concentration of heavy metals ions in the environment have become a serious concern for a number of years. Heavy metals pose serious impacts on human and aquatic life and cause severe health hazards. Amongst heavy metals, cadmium is known for its lethal effects on human health as it easily reacts with enzymes and creates free radicals in the biological system that causes carcinogenicity and other serious diseases. Thus, to tackle this challenge, TX-100 SnO₂ nanoparticles based chemically modified sensor is introduced to assess the quantity of Cd⁺² in the water system. The engineered SnO₂ nanoparticles were electrochemically characterized through cyclic voltammetry and electrochemical impedance spectroscopy to ensure the better charge transfer kinetics and electrocatalytic properties of fabricated sensors. Under the optimized conditions e.g., scan rate 80 mV/s, PBS electrolyte pH 7, and potential window (-0.2 to -1.4 V), the engineered TX-100/SnO₂/GCE-based sensor manifested a phenomenal response for cadmium ions in water media. The LOD and LOQ of developed TX-100/SnO₂/GCE were calculated in the nanomolar range as 0.0084 nM and 0.27 nM. The recovery values of the proposed method for Cd⁺² were found in an acceptable limit that witnesses the effectiveness of the fabricated sensor. Moreover, the excellent stability and anti-interference behavior of the sensor highlights its dynamic profile to be commercially utilized for the determination of Cd⁺² ions in water bodies.

A novel platform based on CoMn2O4-rGO/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode for voltammetric detection of pethidine in the presence morphine and olanzapine

The present work focuses on the development of a new electrochemical platform based on CoMn₂O₄-rGO/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode (CoMn₂O₄-rGO/IL/CPE) for electrochemical determination of pethidine in the presence of biological species. For the first time, the electrooxidation mechanism of pethidine in presences of morphine and olanzapine is investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) technologies. The as-synthesized CoMn₂O₄-rGO nanocomposites are characterized by physicochemical measurements such as X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FT-IR). The obtained results illustrated synergistic interactions between rGO and CoMn₂O₄ structures. Also, to investigate the electrode charge-transfer resistances, electrochemical features of the resulting nanocomposites are studied via electrochemical impedance spectroscopy (EIS) analysis. Based on the result, three segmented linear ranges are observed over the range 0.08-900 μM and detection limit of 0.024 μM. Over the 10.0-40.0 μM ranges of pethidine in phosphate buffer solution (PBS-pH 7.0), suitable diffusion coefficient of 5.67 × 10^-7 cm² s^-1 is evaluated by chronoamperometry technique (CHA). Finally, the CoMn₂O₄-rGO/IL/CPE with high sensitivity, selectivity and repeatability is successfully used for determination of pethidine in real sample and drug formulation.

A zinc oxide nanorods/molybdenum disulfide nanosheets hybrid as a sensitive and reusable electrochemical sensor for determination of anti-retroviral agent indinavir

This work aims to develop an electrochemical sensor for the reusable and selective detection of trace levels of indinavir (IDV) as an anti-retroviral drug by using zinc oxide nano-rods/molybdenum disulfide nanosheets on a screen-printed electrode (ZnO NRs/MoS₂ NSs/SPE). Quantitative IDV detection was achieved using differential pulse voltammetry (DPV). The assay specificity was illustrated using interfering species and exhibited high specificity toward the IDV. The developed displayed a wide dynamic range, from 0.01 to 0.66 and 0.66-7.88 μM in Britton-Robinson (B-R) buffer, with a 0.007 μM limit of detection. The fabricated ZnO NRs/MoS₂ NSs/SPE electrode exhibited high sensitivity, stability, good reproducibility, and repeatability towards the sensing of IDV. It turned out that the hybrid electrochemical sensor's sensing performance was remarkably improved due to the synergistic effect between MoS₂ NSs and ZnO NRs, where the former affords a large active surface area and quick electron transfer. The reported sensor provides a new alternative for electrochemical detection of IDV and could expand the applications of metal nanoparticles in emerging technologies for monitoring drugs in real samples.

A Voltammetric Sensor for the Determination of Hydroxylamine Using a Polypyrrole Nanotubes-Modified Electrode

In this work, we develop an electrochemical sensor using a polypyrrole nanotubes-modified graphite screen-printed electrode (PPy NTs/GSPE) for sensing hydroxylamine. The PPy NTs/GSPE-supported sensor has an appreciable electrocatalytic performance and great stability for hydroxylamine oxidation. Compared to a bare graphite screen-printed electrode, we demonstrate that using the PPy NTs/GSPE leads to a significant reduction in the oxidation potential of hydroxylamine. The standard curve shows a linear relationship ranging from 0.005 to 290.0 μM (R2  =  0.9998), with a high sensitivity (0.1349 μA/μM) and a narrow limit of detection (LOD) of 0.001 μM. In addition, the PPy NTs/GSPE has satisfactory outcomes for hydroxylamine detection in real specimens.

Highly Selective and Sensitive Voltammetric Method for the Detection of Catechol in Tea and Water Samples Using Poly(gibberellic acid)-Modified Carbon Paste Electrode

Despite the wide range of applications of catechol (CC) in agrochemical, petrochemical, textile, cosmetics, and pharmaceutical industries, its exposure to the environment leads to health issues as it is carcinogenic. This increased the concern over the risk of exposure level of CC in the environment, and monitoring its level has become critical. In this work, we report the fabrication of poly-gibberellic acid-modified carbon paste electrode (PGBAMCPE) to be a simple, viable, and effective electrochemical electrode for the determination of CC. This was synthesized by a simple electropolymerization method by the cyclic voltammetry (CV) technique. The electrodes were characterized by field emission electron microscopy, energy-dispersive X-ray spectroscopy, and electrochemical impedance spectroscopy. Compared to the bare carbon paste electrode, the sensitivity for CC fortified at PGBAMCPE in both CV and differential pulse voltammetry (DPV). We succeeded attaining a lower detection limit of 0.57 μM by the DPV method. The developed electrode was observed to be highly conductive, transducing, stable, and reproducible and was highly selective with anti-interfering properties from the determination of CC with hydroquinone simultaneously. The applicability of the electrode was confirmed from the detection CC in tea and water samples with good recoveries. This substantiates that PGBAMCPE is promising and consistent for the rapid monitoring of CC-contaminated area and clinical diagnosis.

Magnetic nanoparticles based on cerium MOF supported on the MWCNT as a fluorescence quenching sensor for determination of 6-mercaptopurine

In this study, a new magnetic nanocomposite was developed as an efficient and fast-response fluorescence quenching sensor for determination of anticancer drug 6-mercaptopurine (6-MP). For this purpose, the needle-shape fluorescence metal-organic framework of cerium (Ce-MOF) were successfully synthesized on the surface of multiwalled carbon nanotubes using 1,3,5-benzenetricarboxylic acid ligand via a facile solvothermal assisted route and magnetized. The accuracy of the proposed synthesis was confirmed using the FT-IR, FE-SEM, XRD, and VSM methods. The obtained product as presented the fluorescence emission in 331 nm by excitation of 293 nm in excitation/emission slit widths of 10.0 nm. The operation of suggested method is based on quenching the fluorescence signal in accordance with increasing the 6-MP concentration. The proposed assay effectively detected the trace amount of 6-MP in the linear range of 1.0 × 10^-6 to 7 × 10^-5 M. The limit of detection and limit of quantification were obtained as 8.6 × 10^-7 and 2.86 × 10^-6 M, respectively. The analyte molecule was determined in real samples with satisfactory recoveries between 98.75 and 105.33.

Screen-printed graphite electrode modified with Co3O4nanoparticles and 2D graphitic carbon nitride as an effective electrochemical sensor for 4-aminophenol detection

We fabricated a new electrochemical 4-aminophenol sensor based on a nanocomposite of Co₃O₄nanoparticles and graphite carbon nitride (Co₃O₄@g-C₃N₄), used for the modification of a screen-printed electrode (Co₃O₄@g-C₃N₄/SPE). The synthesized nanocomposite was characterized using field-emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray diffraction and Fourier transform-infrared (FT-IR) techniques. The electro-oxidation of 4-aminophenol in phosphate buffer solution (pH = 7.0) was investigated via cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The peak current of oxidation in the optimized conditions had a linear relationship with various 4-aminophenol contents (0.05-780.0μM) with a correlation coefficient of 0.9996 and the limit of detection (S/N = 3) of 1.5 × 10^-8M. The developed method was successful to determine 4-aminophenol in real specimens, with acceptable outcomes.

Sulfonated calixarene modified Poly(methyl methacrylate) nanoparticles:A promising adsorbent for Removal of Vanadium Ions from aqueous media

The poly (methyl methacrylate) (PMMA)-based nanoparticle was synthesized by surfactant-free emulsion polymerization method and then post modified with Calixarene using (3-Aminopropyl)triethoxysilane organo-silane as a linker after OH-treatment. The prepared structure was applied for efficient adsorption of Vanadium ions in the aqueous solution after characterization by FT-IR, SEM, TEM, DLS, and EDX. Additional investigations discovered that the prepared adsorbent has a good capacity to adsorb vanadium ions. The effect of key experimental factors was studied to find the optimal point of adsorbent efficiency including the initial concentration of analyte, sorbent dosage, pH of the solution, contact time, and type/quantity of the eluents. It was specified, the maximum adsorption capacity for the synthesized nanoparticles was obtained about 322 mg g^-1. The adsorption mechanism was revealed that the model of Langmuir isotherm well-matched compared to the others due to the calculated equilibrium data. Besides, the kinetics of the adsorption process was fitted with pseudo-second-order. Eventually, the prepared adsorbent was successfully applied in vanadium adsorption from real water media.

Removal of pharmaceuticals (diclofenac and amoxicillin) by maltodextrin/reduced graphene and maltodextrin/reduced graphene/copper oxide nanocomposites

Due to the scarcity of water and the growing industrialization, pharmaceutical wastewater treatment is of particular importance. For this reason, it is necessary to achieve an efficient method to eliminate all types of pharmaceutical pollutants. Herein, synthetic nano-composite is proposed to take a step towards improving the operation of removing pharmaceutical contaminants from the environment and aquatic and industrial effluents. Binary (maltodextrin/reconstituted graphene nanocomposite) and ternary (maltodextrin/reconstituted graphene nanocomposite/copper oxide) nanocomposites were prepared and characterized using, FT-IR, FESEM-EDS, TEM, DLS, and XRD. The nanocomposites were used to eliminate diclofenac and amoxicillin as Pharmaceuticals. The removal of amoxicillin at a concentration of 30 mg/L with an adsorbent dose of 0.05 g and a pH of 7.4 and an optimal temperature of 20 °C in 10 min has the highest removal rate of 86%. In addition, diclofenac with nano-adsorbents prepared under optimal conditions, including an initial concentration of 20 mg/L, adsorbent dose of 0.05 g, adsorption time of 7 min, a temperature of 20 °C and a pH of 7, has the highest removal efficiency of 94%. The results indicated that the prepared nanocomposites are alternative adsorbents to remove Pharmaceuticals from water.

Design, synthesis, and characterization of novel eco-friendly chitosan-AgIO3 bionanocomposite and study its antibacterial activity

This work reports a facile and green approach to preparing AgIO₃ nanoparticles decorated with chitosan (chitosan-AgIO₃). The bionanocomposite was fully characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM) images, energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD). The antibacterial effect of chitosan-AgIO₃ bionanocomposite was investigated for Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus saprophyticus, Escherichia coli, and Staphylococcus aureus as pathogen microorganisms via the plate count method, disk diffusion method, and optical density (OD) measurements. The antibacterial performance of the bionanocomposite was compared with two commercial drugs (penicillin and silver sulfadiazine) and in some cases, the synthesized bionanocomposite has a better effect in the eradication of bacteria. The bionanocomposite represented great antibacterial properties. Flow cytometry was performed to investigate the mechanism of bionanocomposite as an antibacterial agent. Reactive oxygen species (ROS) production was responsible for the bactericidal mechanisms. These results demonstrate that the chitosan-AgIO₃ bionanocomposite, as a kind of antibacterial material, got potential for application in a broad range of biomedical applications and water purification. The design and synthesis of green and biodegradable antibacterial materials with simple processes and by using readily available materials cause the final product to be economically affordable and could be scaled in different industries.

Advanced microplastic monitoring using Raman spectroscopy with a combination of nanostructure-based substrates

Micro(nano)plastic (MNP) pollutants have not only impacted human health directly, but are also associated with numerous chemical contaminants that increase toxicity in the natural environment. Most recent research about increasing plastic pollutants in natural environments have focused on the toxic effects of MNPs in water, the atmosphere, and soil. The methodologies of MNP identification have been extensively developed for actual applications, but they still require further study, including on-site detection. This review article provides a comprehensive update on the facile detection of MNPs by Raman spectroscopy, which aims at early diagnosis of potential risks and human health impacts. In particular, Raman imaging and nanostructure-enhanced Raman scattering have emerged as effective analytical technologies for identifying MNPs in an environment. Here, the authors give an update on the latest advances in plasmonic nanostructured materials-assisted SERS substrates utilized for the detection of MNP particles present in environmental samples. Moreover, this work describes different plasmonic materials-including pure noble metal nanostructured materials and hybrid nanomaterials-that have been used to fabricate and develop SERS platforms to obtain the identifying MNP particles at low concentrations. Plasmonic nanostructure-enhanced materials consisting of pure noble metals and hybrid nanomaterials can significantly enhance the surface-enhanced Raman scattering (SERS) spectra signals of pollutant analytes due to their localized hot spots. This concise topical review also provides updates on recent developments and trends in MNP detection by means of SERS using a variety of unique materials, along with three-dimensional (3D) SERS substrates, nanopipettes, and microfluidic chips. A novel material-assisted spectral Raman technique and its effective application are also introduced for selective monitoring and trace detection of MNPs in indoor and outdoor environments.

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Polyoxometalates-graphene nanocomposites modified electrode for electro-sensing detection of Sudan I in food

Sudan I, a lipophilic azo dye -dye, is desirable and urgent to be accurate detected due to its increasing levels and high toxicity in food and environmental monitoring and analysis. Herein, a sensitive electrochemical sensor for Sudan I was established based on a new K₁₀P₂W₁₈Fe₄(H₂O)₂O₆₈ functionalized carbon nanomaterials (Fe₄P₂W₁₈-GNPS). The electrode modified nanocomposite, Fe₄P₂W₁₈-GNPS, was successfully fabricated and characterized by FTIR, SEM and UV-vis. The effective combination of Fe₄P₂W₁₈ and graphene exhibited high electrocatalytic activity towards the oxidation of Sudan I, promote charge transfer, and more sensing sites. Under optimized experimental conditions, the proposed differential pulse voltammetry (DPV) showed excellent analytical performances for Sudan I with the limit of detection (LOD) of 5 nM (S/N = 3), the sensitivity of 13.10 μA·μM^-1cm^-2 at the 0.005-2 μM and 0.39 μA·μM^-1cm^-2 at 10-200 μM. The stability and reproducibility make the electrochemical sensor suitable for detecting the Sudan I in food.