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Monitoring fenitrothion (FNT) residues in food and the environment is crucial due to its high environmental toxicity. In this study, we developed a sensitive, reliable electrochemical method for detecting FNT by using screen-printed carbon electrodes (SPCE) modified with porous graphene oxide (PGO) nanosheets. PGO surface properties have been meticulously characterized using advanced spectroscopic techniques. Electrochemical impedance spectroscopy and cyclic voltammetry were used to test the electrochemical properties of the PGO-modified sensor. The PGO-modified sensor exhibited remarkable sensitivity, achieving a detection limit as low as 0.061 µM and a broad linear range of 0.02-250 µM. Enhanced performance is due to PGO's high surface area and excellent electrocatalytic properties, which greatly improved electron transfer. Square wave voltammetry was used to demonstrate the sensor's efficacy as a real-time, on-site monitoring tool for FNT residues in fruit and water. The outstanding performance of the PGO/SPCE sensor underscores its applicability in ensuring food safety and environmental protection.
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The design of an efficient electrocatalyst for effective trace level determinations of noxious synthetic and or biological compounds is the unceasingly noteworthy conceptual approach for rapid technology. In this work, we designed a magnesium-aluminum layered double hydroxides (Mg-Al LDHs) nanocatalyst and applied it to the electrocatalytic determination of an extremely carcinogenic catechol sensor. A coprecipitation method was employed for synthesizing the nanocatalyst, and the structure, porous nature, and morphology were confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption-desorption isotherm, field emission-scanning electron microscopy, and transmission electron microscopy. The elemental composition was observed by energy dispersive X-ray analysis. The electrochemical studies were investigated with the help of cyclic voltammetry and differential pulse voltammetry techniques. The Mg-Al LDHs-based electrocatalyst was used to detect catechol by electrochemical measurements with different parameters. The proposed catechol sensor shows a wide dynamic range (0.007-200 µM) with a lower level of detection (2.3 nm) and sensitivity (3.57 µA µM-1 cm-2). The excellent sensor performance is attributed to the high surface area, fast electron transfer, more active sites, and excellent flexibility. This study depicts the proposed sensor as probable to practical in a scientific investigation. In addition, the modified electrode showed greater selectivity and was used in the detection of fatal contaminants in instant treatment strategies. Moreover, the Mg-Al LDHs confirmed auspicious real sample scrutiny with noteworthy retrieval outcomes in lake water samples which exposed improved consequences.
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Alumínio , Técnicas Eletroquímicas , Catecóis , Técnicas Eletroquímicas/métodos , Hidróxidos , Limite de Detecção , MagnésioRESUMO
We prepared a naturally occurring flavanoid namely quercetin from tea leaves and analyzed by Absorption, Emission, FT-IR, 1H, 13C nmr spectra and ESI-MS analysis. The inclusion behavior of quercetin in cyclodextrins like α-, ß-, γ-, per-6-ABCD and mono-6-ABCD cavities were supported such as UV-vis., Emission, FT-IR and ICD spectra and energy minimization studies. From the absorption and emission results, the type of complexes formed were found to depend on stoichiometry of Host:Guest. FT-IR data of CD complexes of quercetin supported inclusion complex formation of the substrate with α-, ß- and γ-CDs. The inclusion of host-guest complexation of quercetin with α-, ß-, γ-CDs, per-6-ABCD and mono-6-ABCDs provides very valuable information about the CD:quercetin complexes, the study also shows that ß-CD complexation improves water solubility, chemical stability and bioavailability of quercetin. Besides, phase solubility studies also supported the formation of 1:1 drug-CD soluble complexes. All these spectral results provide insight into the binding behavior of substrate into CD cavity in the order per-6-ABCD > Mono-6-ABCD > γ-CD > ß-CD > α-CD. The proposed model also finds strong support from the fact with excess CD this exciton coupling disappears indicates the formation of only 1:1 complex.
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Ciclodextrinas , beta-Ciclodextrinas , Quercetina/química , Espectroscopia de Infravermelho com Transformada de Fourier , beta-Ciclodextrinas/química , Modelos Moleculares , Ciclodextrinas/química , SolubilidadeRESUMO
This work presents a hydrothermal method followed by a sonochemical treatment for synthesizing tantalum decorated on iron selenide (Ta/FeSe2) integrated with nitrogen-doped graphene (NGR) as a susceptible electrode material for detecting trolox (TRX) in berries samples. The surface morphology, structural characterizations, and electrochemical performances of the synthesized Ta/FeSe2/NGR composite were analyzed via spectrophotometric and voltammetry techniques. The GCE modified with Ta/FeSe2/NGR demonstrated an impressive linear range of 0.1 to 580.3 µM for TRX detection. Additionally, it achieved a remarkable limit of detection (LOD) of 0.059 µM, and it shows a high sensitivity of 2.266 µA µÐ-1 cm-2. Here, we used density functional theory (DFT) to investigate the structures of TRX and TRX quinone and the locations of energy levels and electron transfer sites. The developed sensor exhibits significant selectivity, satisfactory cyclic and storage stability, and notable reproducibility. Moreover, the practicality of TRX was assessed in different types of berries, yielding satisfactory recoveries.
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Cromanos , Frutas , Grafite , Nitrogênio , Tantálio , Grafite/química , Frutas/química , Nitrogênio/química , Tantálio/química , Cromanos/química , Cromanos/análise , Teoria da Densidade Funcional , Técnicas Eletroquímicas , Limite de Detecção , Eletrodos , Ferro/química , Ferro/análiseRESUMO
Current commercial separators used in lithium-ion batteries have inherent flaws, especially poor thermal stability, which pose substantial safety risks. This study introduces a high-safety composite membrane made from electrospun poly(vinyl alcohol)-melamine (PVAM) and polyvinylidene fluoride (PVDF) polymer solutions via a dip coating method, designed for high-voltage battery systems. The poly(vinyl alcohol) and melamine components enhance battery safety, while the PVDF coating improves lithium-ion conductivity. The dip-coated PVDF/Esp-PVAM composite separators were evaluated for electrolyte uptake, contact angle, thermal stability, porosity, electrochemical stability and ionic conductivity. Notably, our Dip 1 % PVDF@Esp-PVAM composite separator exhibited excellent wettability and a lithium-ion conductivity of approximately 7.75 × 10â»4 S cmâ»1 at room temperature. These separators outperformed conventional PE separators in half-cells with Ni-rich NCM811 cathodes, showing exceptional cycling stability with 93.4 % capacity retention after 100 cycles at 1C/1C, as compared to 84.8 % for PE separators. Our Dip 1 % PVDF@Esp-PVAM composite separator demonstrates significant potential for enhancing the long-term durability and high-rate performance of lithium-ion batteries, making it a promising option for long-term energy storage applications.
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In this work, we designed tetragonal nanogravel structured dysprosium vanadate Dy(VO4) nanoparticles unified with oxidized carbon nanofiber (f-CNF) denoted as Dy(VO4)/f-CNF nanocomposite for the low potential determination of antiprotozoal drug metronidazole (MEZ). The physicochemical properties of novel Dy(VO4)/f-CNF nanocomposite were analyzed through microscopic and spectroscopic techniques and obtained results express nanocomposite formed with desired surface morphology, crystalline phase, atomic vibrational modes, and preferred elemental compositions. The electrocatalytic activity of Dy(VO4)/f-CNF nanocomposite was examined with a disposable screen-printed electrode (SPCE) via cyclic voltammetry (CV) and linear sweep voltammetry technique (LSV) with a conventional three-electrode system. Dy(VO4)/f-CNF/SPCE delivers a higher active surface area recommends superior electrocatalytic activity which is favorable for the MEZ sensor. Electrocatalytic reduction of MEZ occurred with lower reduction potential (-0.55 V) with dynamic linear range (1.5-1036.9 µM), lower detection limit (6 nm), LOQ (0.022 µM), and higher sensitivity (1.12 µA µM-1 cm2). The anti-interference studies retain its actual current without any shift in cathodic potential. Besides, the practical feasibility outcomes with higher cathodic current with the higher recovery rate and RSD in human blood sample, urine sample, and lake water as a real samples. Thus, Dy(VO4)/f-CNF nanocomposite modified SPCE considers being a potential candidate for the MEZ sensor.
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Nanofibras , Preparações Farmacêuticas , Carbono , Disprósio , Técnicas Eletroquímicas , Eletrodos , Humanos , Metronidazol , VanadatosRESUMO
Flutamide is a non-steroidal antiandrogen drug and widely used in the treatment of prostatic carcinoma. Nevertheless, the excessive intake and improper disposal could affect the living organisms. In this work, we have synthesized a new nanocomposite based on ZnMn2O4 nanoparticles and porous reduced graphene oxide nanosheets (ZnMn2O4-PGO) for the electrocatalytic detection of flutamide (FLU) drug. The crystallinity and morphological properties of ZnMn2O4-PGO composite examined by different characterization techniques such as X-ray diffraction, Raman spectroscopy and so on. The fabricated ZnMn2O4-PGO nanocomposite modified electrode exhibited superior electrocatalytic performance to FLU drug in an optimized pH electrolyte. Fascinatingly, the electrode received a wide linear range (0.05-3.5⯵M) with limit of detection of 8â¯nM. Besides, the developed ZnMn2O4-PGO nanocomposite electrode showed good sensitivity 1.05 µAµM-1 cm-2 and excellent selectivity for FLU detection in presence of various interfering species. A developed disposable electrode was scrutinized to determine FLU level in human urine samples by spiking method and the results achieved good recoveries in real sample analysis.
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Grafite , Nanocompostos , Nanopartículas , Preparações Farmacêuticas , Antagonistas de Androgênios , Técnicas Eletroquímicas , Eletrodos , Flutamida , Humanos , PorosidadeRESUMO
Nitroimidazole compounds are widely used antibiotics to encounter anaerobic bacterial and parasitic infections. The wide usage of antibiotic drugs became an ecological contaminant which in turn into potential monitoring. In this regards, we have designed and developed a new electrochemical sensing probe to monitor an antiprotozoal drug, ornidazole (ODZ), with the aid of a glassy carbon electrode (GCE) integrated with manganese molybdate nanorods (MnMoO4) decorated graphene nanosheets (GNS) hybrid materials that prepared by feasible probe sonochemical method (parameters: 2-4 W, 5 mV amp, 20 kHz). The electrochemical investigations of the developed probe were performed by using rapid scan electrochemical workstations namely cyclic voltammetry (CV) and amperometric (i-t) techniques. The as-prepared MnMoO4/GNS nanocomposite was characterized and its purity of nanocomposite formation was confirmed by various analytical techniques like X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy. In addition to that, the textural morphology of the MnMoO4/GNS nanocomposite was examined with the aid of field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). The MnMoO4/GNS nanocomposite rotating disk glassy carbon electrode (RDGCE) plays a crucial role in electrochemical detection of ODZ, which results in excellent anti-interference ability, a lower detection limit of 845 pM, massive linear ranges from 10 to 770 nM, and good sensitivity of about 104.62 µA µM-1 cm-2. From the acquired electrochemical studies, we have developed a disposable electrochemical sensor probe using a low-cost screen-printed carbon electrode (SPCE) with MnMoO4/GNS nanocomposite. The MnMoO4/GNS/SPCE are capably employed in real-time sensing of ODZ in water and urine samples. These electrochemical studies revealed the integral new vision on the electrocatalytic performance of the modified SPCE and also shown excellent amplification results in ultra-trace levels.
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Poluentes Ambientais , Grafite , Nanotubos , Ornidazol , Técnicas Eletroquímicas , Espectroscopia de Infravermelho com Transformada de Fourier , ÁguaRESUMO
This paper describes a simple, selective and sensitive colorimetric sensing of Cr6+ ions using ß-Cyclodextrin (ß-CD) functionalized gold-iron nanoparticles (ß-CD/Au-FeNPs). The sonochemically synthesized nanoparticles are winered in colour due to the SPR band of ß-CD functionalized bimetalic nanoparticles Au-FeNPs. The capping and stabilizing of Au-FeNPs by redox ß-CD is confirmed by FT-IR. The particles are spherical in shape and it posses the effective diameter of 18-20â¯nm. Under optimized conditions, in the presence of Cr6+ the wine red Au-FeNPs solution was turned to colourless, accompanying the broadening and red shifting of SPR band. The ratio between the absorbance wavelength at 573â¯nm to 535â¯nm (A573/A535) is linearly correlated with the Cr6+ concentrations ranging from 50â¯nM to 500â¯nM, with a detection limit of Cr6+ of 2.5â¯nM was achieved for the first time using ß-CD/Au-FeNPs by spectrophotometry. The selectivity of the ß-CD/Au-FeNPs towards other interfering metal ions. Finally the proposed method has been successfully employed for the determination of Cr6+ ion in various industrial waste water with good recoveries.
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Semiconductor materials have been shown to have good photocatalytic behavior and can be utilized for the photodegradation of organic pollutants. In this work, three-dimensional flower-like SnS2 (tin sulfide) was synthesized by a facile hydrothermal method. Core-shell structured SiO2@α-Fe2O3 nanocomposites were then deposited on the top of the SnS2 flowers. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UVâ»Vis Spectroscopy, Brunauerâ»Emmettâ»Teller (BET) surface area analysis, and photoluminescence (PL) spectroscopy. The photocatalytic behavior of the SnS2-SiO2@α-Fe2O3 nanocomposites was investigated by observing the degradation of methylene blue (MB). The results show an effective enhancement of photocatalytic activity for the degradation of MB especially for the 15 wt % SiO2@α-Fe2O3 nanocomposites on SnS2 flowers.
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A simple and facile green process was used for the synthesis of iron nanoparticles (FeNPs) decorated reduced graphene oxide (rGO) nanocomposite by using Ipomoea pes-tigridis leaf extract as a reducing and stabilizing agent. The as-prepared rGO/FeNPs nanocomposite was characterized by transmission electron microscopy, X-ray spectroscopy and Fourier transform infrared spectroscopy. The nanocomposite was further modified on the glassy carbon electrode and used for non-enzymatic sensing of hydrogen peroxide (H2O2). Cyclic voltammetry results reveal that rGO/FeNPs nanocomposite has excellent electro-reduction behavior to H2O2 when compared to the response of FeNPs and rGO modified electrodes. Furthermore, the nanocomposite modified electrode shows 9 and 6 folds enhanced reduction current response to H2O2 than that of rGO and FeNPs modified electrodes. Amperometric method was further used to quantify the H2O2 using rGO/FeNPs nanocomposite, and the response was linear over the concentration ranging from 0.1µM to 2.15mM. The detection limit and sensitivity of the sensor were estimated as 0.056µM and 0.2085µAµM-1cm-2, respectively. The fabricated sensor also utilized for detection of H2O2 in the presence of potentially active interfering species, and found high selectivity towards H2O2.
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Técnicas Eletroquímicas , Peróxido de Hidrogênio/análise , Ferro/química , Nanopartículas Metálicas/química , Nanocompostos/química , Eletrodos , Grafite/química , Concentração de Íons de Hidrogênio , Ipomoea/química , Limite de Detecção , Nanopartículas Metálicas/ultraestrutura , Nanocompostos/ultraestrutura , Oxirredução , Óxidos , Extratos Vegetais/química , Folhas de Planta/químicaRESUMO
A simple and cost effective synthesis of nanomaterials with advanced physical and chemical properties have received much attention to the researchers, and is of interest to the researchers from different disciplines. In the present work, we report a simple and one pot electrochemical synthesis of poly(melamine) entrapped gold nanoparticles (PM-AuNPs) composite. The PM-AuNPs composite was prepared by a single step electrochemical method, wherein the AuNPs and PM were simultaneously fabricated on the electrode surface. The as-prepared materials were characterized by various physicochemical methods. The PM-AuNPs composite modified electrode was used as an electrocatalyst for oxidation of catechol (CC) due to its well-defined redox behavior and enhanced electro-oxidation ability towards CC than other modified electrodes. Under optimized conditions, the differential pulse voltammetry (DPV) was used for the determination of CC. The DPV response of CC was linear over the concentration ranging from 0.5 to 175.5µM with a detection limit of 0.011µM. The PM-AuNPs composite modified electrode exhibits the high selectivity in the presence of range of potentially interfering compounds including dihydroxybenzene isomers. The sensor shows excellent practicality in CC containing water samples, which reveals the potential ability of PM-AuNPs composite modified electrode towards the determination of CC in real samples.
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Catecóis/química , Ouro/química , Nanopartículas Metálicas/química , Nanocompostos/química , Polímeros/química , Triazinas/química , Técnicas Biossensoriais/métodos , Catálise , Técnicas Eletroquímicas , Eletrodos , Limite de Detecção , OxirreduçãoRESUMO
In the present work, we demonstrate the fabrication of laccase biosensor to detect the catechol (CC) using laccase immobilized on graphene-cellulose microfibers (GR-CMF) composite modified screen printed carbon electrode (SPCE). The direct electrochemical behavior of laccase was investigated using laccase immobilized different modified SPCEs, such as GR/SPCE, CMF/SPCE and GR-CMF/SPCE. Compared with laccase immobilized GR and CMF modified SPCEs, a well-defined redox couple of CuI/CuII for laccase was observed at laccase immobilized GR-CMF composite modified SPCE. Cyclic voltammetry results show that the as-prepared biosensor has 7 folds higher catalytic activity with lower oxidation potential towards CC than SPCE modified with GR-CMF composite. Under optimized conditions, amperometric i-t method was used for the quantification of CC, and the amperometric response of the biosensor was linear over the concertation of CC ranging from 0.2 to 209.7 µM. The sensitivity, response time and the detection limit of the biosensor for CC is 0.932 µMµA-1 cm-2, 2 s and 0.085 µM, respectively. The biosensor has high selectivity towards CC in the presence of potentially active biomolecules and phenolic compounds. The biosensor also accessed for the detection of CC in different water samples and shows good practicality with an appropriate repea.
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Técnicas Biossensoriais/instrumentação , Catecóis/análise , Eletroquímica/instrumentação , Lacase/química , Nanotubos de Carbono/química , Celulose/química , Eletroquímica/métodos , Eletrodos , Grafite/químicaRESUMO
Excess nitrite (NO2-) concentrations in water supplies is considered detrimental to the environment and human health, and is associated with incidence of stomach cancer. In this work, the authors describe a nitrite detection system based on the synthesis of gold nanoparticles (AuNPs) on reduced graphene oxide (rGO) using an aqueous solution of chitosan and succinic acid. The AuNPs-rGO nanocomposite was confirmed by different physicochemical characterization methods including transmission electron microscopy, elemental analysis, X-ray diffraction, UV-visible (UV-vis) and Fourier transform infrared spectroscopy. The AuNPs-rGO nanocomposite was applicable to the sensitive and selective detection of NO2- with increasing concentrations quantifiable by UV-vis spectroscopy and obvious to the naked eye. The color of the AuNPs-rGO nanocomposite changes from wine red to purple with the addition of different concertation of NO2-. Therefore, nitrite ion concentrations can be quantitatively detected using AuNPs-rGO sensor with UV-vis spectroscopy and estimated with the naked eye. The sensor is able to detect NO2- in a linear response ranging from 1 to 20 µM with a detection limit of 0.1 µM by spectrophotometric method. The as-prepared AuNPs-rGO nanocomposite shows appropriate selectivity towards NO2- in the presence of potentially interfering metal anions.
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We report a novel and sensitive amperometric sensor for chlorpromazine (CPZ) based on reduced graphene oxide (RGO) and polydopamine (PDA) composite modified glassy carbon electrode. The RGO@PDA composite was prepared by electrochemical reduction of graphene oxide (GO) with PDA. The RGO@PDA composite modified electrode shows an excellent electro-oxidation behavior to CPZ when compared with other modified electrodes such as GO, RGO and GO@PDA. Amperometric i-t method was used for the determination of CPZ. Amperometry result shows that the RGO@PDA composite detects CPZ in a linear range from 0.03 to 967.6 µM. The sensor exhibits a low detection limit of 0.0018 µM with the analytical sensitivity of 3.63 ± 0.3 µAµM(-1 )cm(-2). The RGO@PDA composite shows its high selectivity towards CPZ in the presence of potentially interfering drugs such as metronidazole, phenobarbital, chlorpheniramine maleate, pyridoxine and riboflavin. In addition, the fabricated RGO@PDA modified electrode showed an appropriate recovery towards CPZ in the pharmaceutical tablets.