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1.
Environ Res ; 238(Pt 2): 117261, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37775004

RESUMO

In this work, novel modified electrode (MXene/MIL-101(Cr)/GCE) are manufactured through simple layer-by-layer immobilization procedure. The fabricated electrochemical sensor was utilized for electrochemical sensing of flutamide in biological fluids. The immobilization of both MXene and metal-organic framework (MOF) materials on the electrode surface could improve the electrochemical performance of the modified glassy carbon electrode (GCE) towards flutamide due to the synergic effects. The established sensor illustrated the significant sensing ability for the determination of flutamide. The influence of solution pH and volume ratio of MXene/MIL-101(Cr) on electrochemical performance of the modified GCE was researched and optimized. The sensor demonstrated a favorable detection limit of 0.009 µM and a linear range of 0.025-100 µM using differential pulse voltammetry (DPV) technique. The suggested assay illustrated an excellent sensing efficiency towards flutamide in body fluids with recoveries ranging from 97.7% to 102.5%, which indicates its potential in real matrices. In addition, the MXene/MIL-101(Cr)/GCE was illustrated some advantages including simple preparation, good selectivity and reproducibility, and rapid flutamide detection.


Assuntos
Antineoplásicos , Neoplasias da Próstata , Humanos , Masculino , Flutamida , Reprodutibilidade dos Testes , Seguimentos , Carbono
2.
Environ Res ; 219: 115154, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36574798

RESUMO

Bismuth molybdate has three phases α-Bi2MoO6, ß-Bi2Mo2O9, and γ- Bi2Mo3O12, each of which has unique properties that distinguish them from each other. Among them, Bi2MoO6 and Bi2Mo3O12 have the most stability. In this research, γ-Bi2MoO6@Bi2Mo2.66W0.34O12 core‒shell nanofibers were deposited on the stainless steel mesh as effective and low‒cost substrate. The co‒axial electrospinning as a simple method was applied to form nanofibers on the substrate. Both of the abovementioned bismuth molybdates contents include different crystal facets, controlling the Red‒Ox properties. α-Bi2MoO6 possesses the vast numbers of oxygen vacancies in Mo-O bonding makes the oxidant {100} crystal facet. Likewise, γ‒Bi2Mo2.66W0.34O12 contains brittle facet of {010} with high concentration of Oxygen vacancies resulted in oxidative capability of the core‒shell composite. The obtained data indicated the key role of OH radical through photocatalytic reactions and a new heterojunction having direct Z‒scheme standing.


Assuntos
Bismuto , Nanofibras , Bismuto/química , Molibdênio/química , Oxigênio/química
3.
Environ Res ; 237(Pt 2): 117030, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37659641

RESUMO

An effective biosensing platform is described based on halloysite nanotube/carbon composite decorated with Pd nanoparticles (HNT/C@Pd NPs). A novel electrochemical aptasensor was designed using the proposed nano-platform to determine human epidermal growth factor receptor 2 (HER2), a breast cancer biomarker. Inherently, aptasensing interfaces provide high sensitivity and selectivity for tumor markers owing to the high specific surface area of HNT/C and good conductivity stems from deposition of Pd NPs into HNT/C composite. With a correlation coefficient of 0.996, the electrochemical aptasensor demonstrated a wide linear range from 0.03 ng/mL to 9 ng/mL. The limit of detection (LOD) of the established assay was 8 pg/mL based on S/N = 3 method. Further, the designed biosensor demonstrated acceptable selectivity, good reproducibility, and high stability. The applicability of the impedimetric sensor in human serum samples was also examined and compared to enzyme-linked immunosorbent assay (ELISA) assay (p-value >0.05). Based on the results, it was found that the proposed methodology can be used in quantification of breast cancer markers for early diagnosis and treatment.

4.
Environ Res ; 233: 116462, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37352956

RESUMO

Nanocomposites have gained attention due to their variety of applications in different fields. In this research, we have reported a green synthesis of a bi-metallic nanocomposite of nickel and zinc using an aqueous extract of Citrus sinensis in the presence of chitosan (Ni/Zn@orange/chitosan). The nanocomposite was characterized using different techniques. We have examined various applications for Ni/Zn@orange/chitosan. The NPs were manufactured in spherical morphology with a particle range size of 17.34-90.51 nm. Ni/Zn@orange/chitosan showed an acceptable ability to remove dyes of Congo red and methyl orange from an aqueous solution after 80 min furthermore, it uptaking the drug mefenamic acid from a solution. Ni/Zn@orange/chitosan also exhibited great photocatalytic activity in synthesizing benzimidazole using benzyl alcohol and o-phenylenediamine. Ni/Zn@orange/chitosan was found as a potent electrochemical sensor to determine glucose. In the molecular and cellular section of the current research, the cells with composite nanoparticles were studied by MTT way about the anti-breast adenocarcinoma potentials malignant cell lines. The IC50 of composite nanoparticles were 320, 460, 328, 500, 325, 379, 350, and 396 µg/mL concering RBA, NMU, SK-BR-3, CAMA-1, MCF7, AU565, MDA-MB-468, and Hs 281.T breast adenocarcinoma cell lines, respectively. The results revealed the newly synthesized nanocomposite is a potent photocatalyst, dye pollution removal agent, and an acceptable new drug to treat breast cancer.


Assuntos
Adenocarcinoma , Quitosana , Nanocompostos , Nanopartículas , Humanos , Quitosana/química , Nanopartículas/química , Corantes/química , Zinco , Água , Nanocompostos/química
5.
Environ Res ; 238(Pt 1): 117080, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37683787

RESUMO

Our investigation aimed to create and manufacture an electrochemical impedance sensor with the purpose of improving the detection efficiency of melatonin (ME). To achieve this objective, we employed gold nanoparticles coated on polydopamine formed in glassy carbon electrodes (AuNPs/PDA/GCE) as a means to enhance the sensor's capabilities. A novel approach employing the signal-off strategy and electrochemical impedance spectroscopy (EIS) technique was utilized to determine ME. When the AuNPs/PDA/GCE electrode was immersed in a buffered solution containing ME, and the oxidation current of AuNPs was recorded, it was observed that the oxidation current of AuNPs decreased upon the introduction of ME molecules. The decrease in electrical current can be ascribed to the inhibitory impact of ME molecule adsorption on the electrode surface with applying -0.2 V for 150 s in acetate buffer solution (ABS) (pH, 5) through various mechanisms, which hinders the electron transfer process crucial for AuNPs oxidation. Consequently, by utilizing EIS, various concentrations of ME were quantified spanning from 1 to 18 pM. Moreover, the ME sensor achieved an impressive detection limit of 0.32 pM, indicating its remarkable sensitivity in detecting low concentrations of ME. Importantly, these novel sensors demonstrated exceptional attributes in terms of sensitivity, specificity, stability, and repeatability. The outstanding performance of these sensors, coupled with their desirable attributes, establishes their considerable potential for a wide range of practical applications. These applications encompass various fields such as clinical diagnostics, pharmaceutical analysis, environmental monitoring, and industrial quality control, where accurate and sensitive detection of ME is of utmost importance.


Assuntos
Melatonina , Nanopartículas Metálicas , Humanos , Ouro/química , Técnicas Eletroquímicas/métodos , Limite de Detecção , Nanopartículas Metálicas/química , Carbono/química , Preparações Farmacêuticas
6.
Environ Res ; 238(Pt 1): 117081, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37683794

RESUMO

In this work, an environmentally friendly strategy was used to synthesize gold nanoparticles (Au NPs) using Olea europaea (olive) fruit. Transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) were used to characterize the physicochemical properties of the synthesized NPs. An Au NPs modified glassy carbon electrode was used to investigate the direct electrochemical oxidation of hydrazine. The suggested hydrazine sensor has good performance, such as a wide linear range (2.5-275 µM), low limit of detection (0.09 µM), notable selectivity and excellent reproducibility (RSD = 2.2%). The in-vitro cytotoxicity of three human cancer cell lines (KATOIII, NCI-N87, and SNU-16) was also explored with various concentrations of Au NPs prepared from olive fruit extract. Bio-synthesized Au NPs were found to have cytotoxic properties against gastric cancer in humans based on MTT assay protocol. The obtained results show that green synthesized Au NPs can be successfully employed in electrochemical sensing and cancer treatment applications.


Assuntos
Nanopartículas Metálicas , Neoplasias Gástricas , Humanos , Nanopartículas Metálicas/química , Ouro/química , Reprodutibilidade dos Testes , Hidrazinas
7.
Environ Res ; 222: 115338, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36702186

RESUMO

p_Aminophenol, namely 4-aminophenol (4-AP), is an aromatic compound including hydroxyl and amino groups contiguous together on the benzene ring, which are suitable chemically reactive, amphoteric, and alleviating agents in nature. Amino phenols are appropriate precursors for synthesizing oxazoles and oxazines. However, since the toxicity of aniline and phenol can harm human and herbal organs, it is essential to improve a reliable technique for the determination of even a trace amount of amino phenols, as well as elimination or (bio)degradation/photodegradation of it to protect both the environment and people's health. For this purpose, various analytical methods have been suggested up till now, including spectrophotometry, liquid chromatography, spectrofluorometric and capillary electrophoresis, etc. However, some drawbacks such as the requirement of complex instruments, high costs, not being portable, slow response time, low sensitivity, etc. prevent them to be employed in a wide range and swift in-situ applications. In this regard, besides the efforts such as (bio)degradation/photodegradation or removal of 4-AP pollutants from real samples, electroanalytical techniques have become a promising alternative for monitoring them with high sensitivity. In this review, it was aimed to emphasize and summarize the recent advances, challenges, and opportunities for removal, degradation, and electrochemical sensing 4-AP in real samples. Electroanalytical monitoring of amino phenols was reviewed in detail and explored the various types of electrochemical sensors applied for detecting and monitoring in real samples. Furthermore, the various technique of removal and degradation of 4-AP in industrial and urban wastes were also deliberated. Moreover, deep criticism of multifunctional nanomaterials to be utilized as a catalyst, adsorbent/biosorbent, and electroactive material for the fabrication of electrochemical sensors was covered along with their unique properties. Future perspectives and conclusions were also criticized to pave the way for further studies in the field of application of up-and-coming nanostructures in environmental applications.


Assuntos
Poluentes Ambientais , Nanoestruturas , Humanos , Aminofenóis/análise , Poluentes Ambientais/análise , Fenóis/análise , Nanoestruturas/química
8.
Environ Res ; 231(Pt 2): 116177, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37201707

RESUMO

In this work, a new dendrimer modified magnetic graphene oxide (GO) was used as a substrate for electrodeposition of Au nanoparticles. The modified magnetic electrode was employed for sensitive measuring of As(III) ion as a well-established human carcinogen. The prepared electrochemical device exhibits excellent activity towards As(III) detection using the square wave anodic stripping voltammetry (SWASV) protocol. At optimum conditions (deposition potential at -0.5 V for 100 s in 0.1 M acetate buffer with pH 5.0), a linear range from 1.0 to 125.0 µgL-1 with a low detection limit (calculated by S/N = 3) of 0.47 µg L-1 was obtained. In addition to the simplicity and sensitivity of the proposed sensor, its high selectivity against some major interfering agents, such as Cu(II) and Hg(II) makes it an appreciable sensing tool for the screening of As(III). In addition, the sensor revealed satisfactory results for detection of As(III) in different water samples, and the accuracy of obtained data were confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) setup. Accounting for the high sensitivity, remarkable selectivity and good reproducibility, the established electrochemical strategy has great potential for analysis of As(III) in environmental matrices.


Assuntos
Ouro , Nanopartículas Metálicas , Humanos , Ouro/química , Reprodutibilidade dos Testes , Nanopartículas Metálicas/química , Fenômenos Magnéticos
9.
Environ Res ; 239(Pt 2): 117368, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37827366

RESUMO

Cancer monitoring plays a critical role in improving patient outcomes by providing early detection, personalized treatment options, and treatment response tracking. Carbon-based electrochemical biosensors have emerged in recent years as a revolutionary technology with the potential to revolutionize cancer monitoring. These sensors are useful for clinical applications because of their high sensitivity, selectivity, rapid response, and compatibility with miniaturized equipment. This review paper gives an in-depth look at the latest developments and the possibilities of carbon-based electrochemical sensors in cancer surveillance. The essential principles of carbon-based electrochemical sensors are discussed, including their structure, operating mechanisms, and critical qualities that make them suited for cancer surveillance. Furthermore, we investigate their applicability in detecting specific cancer biomarkers, evaluating therapy responses, and detecting cancer recurrence early. Additionally, a comparison of carbon-based electrochemical sensor performance measures, including sensitivity, selectivity, accuracy, and limit of detection, is presented in contrast to existing monitoring methods and upcoming technologies. Finally, we discuss prospective tactics, future initiatives, and commercialization opportunities for improving the capabilities of these sensors and integrating them into normal clinical practice. The review highlights the potential impact of carbon-based electrochemical sensors on cancer diagnosis, treatment, and patient outcomes, as well as the importance of ongoing research, collaboration, and validation studies to fully realize their potential in revolutionizing cancer monitoring.


Assuntos
Técnicas Biossensoriais , Neoplasias , Humanos , Carbono , Estudos Prospectivos , Técnicas Eletroquímicas/métodos , Técnicas Biossensoriais/métodos , Neoplasias/diagnóstico
10.
Environ Res ; 238(Pt 1): 117026, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37659642

RESUMO

Exposure to thallium (Tl), a noxious heavy metal, poses significant health risks to both humans and animals upon ingestion. Therefore, monitoring Tl levels in the environment is crucial to prevent human exposure and reduce the risk of developing severe health problems. This paper presents the development of a highly sensitive Tl ions sensor through surface modification of a glassy carbon electrode with a nanocomposite comprising MnO2 magnetic sepiolite and multi-walled carbon nanotubes (MnO2@Fe3O4/Sep/MWCNT/GCE). Multiple methodologies were employed to assess the performance of the newly developed sensor. By employing square wave anodic stripping voltammetry (SWASV) to optimize the measurement conditions, notable enhancements were observed in the stripping peak currents of Tl (I) on the MnO2@Fe3O4/Sep/MWCNT/GCE surface. The effectiveness of the nanocomposite in facilitating electron transfer between the Tl (I) ions (guest) and the electrode (host) was demonstrated from the enhanced signals observed at the different modified electrode surfaces under optimal conditions. The developed sensor displayed a wide linear range of 0.1-1500 ppb for Tl (I) and a low detection limit of 0.03 ppb for Tl (I). It was found to be selective for Tl (I) ions while remaining unaffected by interfering non-target ions in the presence of the target ions. Despite its simple preparation procedure, the modified electrode exhibited high stability and excellent reproducibility for measuring Tl (I). The outstanding electroanalytical performances of the MnO2@Fe3O4/Sep/MWCNT/GCE electrode enabled its successful use as an ultrasensitive sensor for determining trace amounts of Tl in environmental samples.


Assuntos
Nanotubos de Carbono , Tálio , Animais , Humanos , Reprodutibilidade dos Testes , Compostos de Manganês , Limite de Detecção , Óxidos
11.
Mikrochim Acta ; 187(4): 213, 2020 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-32157452

RESUMO

The stainless steel mesh, in the form of the disk, was coated with graphene oxide and poly(dimethylsiloxane) (GO-PDMS) by sol-gel technique. The coated stainless steel meshes are loaded in the mini-column as solid-phase extraction cartridge for the fast isolation and preconcentration of polycyclic aromatic hydrocarbons (PAHs) from real water samples. The extracted PAHs (naphthalene, acenaphthene, acenaphthylene, anthracene, benz[a]anthracene, fluorene, and pyrene) were quantified by gas chromatography-mass spectrometry. The operation parameters affecting the extraction efficiency including sample volume, desorption conditions, and ionic strength were investigated. At optimized conditions, the linearity of this method is obtained from 0.001 to 20 ng mL-1 with 0.2 to 1.0 pg mL-1 limit of detection. For 5 replicates at 3 spiking levels (0.1, 1, and 10 ng mL-1), the relative standard deviations between 4.0 and 6.3% were achieved. The absolute extraction recovery varied from 89.1 to 94.7%. The enrichment factors were in the range of 2227-2367. The method has been employed in the determination of PAHs in the real water samples including well water, tap water, river water, and wastewater. Relative recoveries are between 95.2 and 100.9%. Graphical abstractSchematic representation of the SPE procedure using the self-assembly SPE cartridge.

12.
Mikrochim Acta ; 185(8): 393, 2018 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-30056501

RESUMO

A magnetic sorbent was fabricated by coating the magnetized graphene oxide with polystyrene (PS) to obtain a sorbent of the type GO-Fe3O4@PS. The chemical composition and morphology of the sorbent were characterized. The sorbent was employed for the enrichment of polycyclic aromatic hydrocarbons (PAHs) from water samples. Various parameters affecting the enrichment were investigated. The PAHs were then quantified by gas chromatography with flame ionization detection. Linear responses were found in the range of 0.03-100 ng mL-1 for naphthalene and 2-methylnaphthalene, and of 0.01-100 ng mL-1 for fluorene and anthracene. The detection limits (at an S/N ratio of 3) range between 3 and 10 pg mL-1. The relative standard deviations (RSDs) for five replicates at three concentration levels (0.05, 5 and 50 ng mL-1) of analytes ranged from 4.9 to 7.4%. The method was applied to the analysis of spiked real water samples. Relative recoveries are between 95.8 and 99.5%, and RSD% are <8.4%. Graphical abstract A magnetic sorbent was fabricated by polystyrene coated on the magnetic graphene oxide for the extraction and preconcentration of PAHs in water samples prior to their determination by gas chromatography with flame ionization detection.

13.
Mikrochim Acta ; 185(7): 320, 2018 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-29881880

RESUMO

The present study describes an electrochemical aptamer-based method for the determination of bisphenol A (BPA). It is making use of gold nanoparticles (AuNPs) immobilized on a conjugate between multiwalled carbon nanotubes and thiol-functionalized magnetic nanoparticles (MWCNT/Fe3O4-SH) that are modified with an aptamer. The nanocomposite was characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, elemental mapping analysis and energy dispersive X-ray diffraction. The aptasensor, typically operated at 0.20 V (vs. Ag/AgCl), has a linear response in the 0.1 to 8 nM BPA concentration range, a low detection limit (0.03 nM), and high sensitivity (86.43 µA nM-1 cm-2). Voltammetric experiments were performed by using the hexacyanoferrate redox system as an electrochemical probe. The results indicate that the presence of AuNPs, magnetic nanoparticles and MWCNTs results a synergistic electrochemical augmentation. The method is highly selective, sensitive, efficient and environmentally friendly. The method was successfully applied to the determination of BPA in spiked real samples. Graphical abstract Aptasensor fabricated by MWCNT/Fe3O4-SH@Au nanocomposite and anti-BPA aptamer. The conformation of aptamer change after BPA binding, triggering a decrease in the electron transfer of Fe(CN)63-/4- on the electrode surface. The observed decline was detectable as a function of BPA concentration.


Assuntos
Aptâmeros de Nucleotídeos/metabolismo , Compostos Benzidrílicos/análise , Técnicas Biossensoriais/métodos , Ouro/química , Nanopartículas de Magnetita/química , Nanocompostos/química , Nanotubos de Carbono/química , Fenóis/análise , Compostos Benzidrílicos/química , Compostos Benzidrílicos/metabolismo , Técnicas Biossensoriais/instrumentação , Eletroquímica , Eletrodos , Limite de Detecção , Fenóis/química , Fenóis/metabolismo
14.
Mikrochim Acta ; 185(1): 15, 2017 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-29594381

RESUMO

The authors describe the preparation of Fe3O4 nanoparticles coated with poly(p-phenylenediamine-co-thiophene). The resulting nanoparticles (NPs) are shown to be viable sorbents for use in magnetic solid-phase extraction (MSPE) of organophosphorus pesticides (OPPs). The coated NPs were characterized by BET, FTIR, scanning electron microscopy and transmission electron microscopy. Following sorption of OPPs and subsequent desorption with dichloromethane, the OPPs were quantified by GC in combination with FID. Under optimal conditions, the preconcentration factors range from 118 to 163. Other figures of merit include (a) a linear response between 0.3 and 500 ng mL-1; (b) detection limits (at an S/N ratio of 3) between 0.1 and 0.3 ng mL-1, and (c) a precision (for n = 5) between 4.7 and 8.1% at concentration levels of 1, 10 and 100 ng mL-1). The nanocomposites can be reused up to 8 times. The method was applied to the analysis of spiked environmental water samples and fruit juices and gave relative recoveries in the range of 88.1 to 99.2%. Graphical abstract Schematic presentation of the synthesis of core-shell magnetic nanoparticles (MNPs) of the type poly(pPDA-co-Th)@Fe3O4, and their application as a sorbent for magnetic solid-phase extraction (MSPE) of organophosphorus pesticides.


Assuntos
Métodos Analíticos de Preparação de Amostras/métodos , Nanopartículas de Magnetita/química , Compostos Organofosforados/análise , Compostos Organofosforados/química , Praguicidas/análise , Fenilenodiaminas/química , Tiofenos/química , Adsorção , Cromatografia Gasosa , Sucos de Frutas e Vegetais/análise , Nanocompostos/química , Polimerização
15.
Mikrochim Acta ; 185(1): 14, 2017 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-29594392

RESUMO

Graphene oxide (GO) was conjugated to magnetite nanoparticles and then coated with poly(methyl methacrylate) to obtain a nanomaterial of the type PMMA@GO-Fe3O4, which is shown to be a viable sorbent for magnetic solid-phase extraction. The nanocomposite was characterized by SEM, TEM, XRD, VSM and FTIR spectroscopy. It was applied to the extraction of the aromatic amines aniline, N,N-dimethylaniline, o-toluidine, and 3-chloroaniline. Under optimal conditions, the preconcentration factors range from 139 to 173. Following desorption with dichloromethane, the amines were quantified by GC. Analytical figures of merit include (a) a linear range extending from 0.007-100 ng mL-1, (b) detection limits between 2 and 6 pg mL-1; and (c) relative standard deviations between 5.9 and 8.6% (for n = 5; at 0.05, 5.0 and 50 ng mL-1 levels, respectively). The method was successfully applied to the determination of aromatic amines in spiked real water samples and gave recoveries in the range of 90.3%-99.0%. Graphical abstract A magnetic sorbent was fabricated by deposition of poly(methyl methacrylate) onto Fe3O4-magnetized graphene oxide. It was applied to the extraction and preconcentration of aromatic amines from water samples prior to their gas chromatography-flame ionization detector (GC-FID) determination.

16.
Chemosphere ; 346: 140579, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38303391

RESUMO

Molybdenum-doped BiVO4 thin films were uniformly coated on indium-doped tin oxide (ITO) substrates via a facile modified hot spin coating (HSC) technique. The prepared layers were used as photoanode in a photoelectrochemical (PEC) cell. Different percentage of Mo dopant was examined to maximize the photo-current density (J) of the layers. The highest J value (872 ± 8 µA/cm2) was obtained by 5 atomic% of Mo doping. After that, the surface topographies of these samples were changed by varying the initial precursor concentration from 27 to 80 mM. The relation between surface topographies and the PEC activity of Mo-doped BiVO4 thin films was investigated from microscopic point of view by calculating the surface roughness exponent of α, and a mechanism for the PEC activity of Mo-doped BiVO4 photoanodes was proposed accordingly. The sample with a small roughness exponent provided a surface with jagged microscopic fluctuations which may trap the air molecules between the electrolyte and sample surface, hindering the fine atomic interaction for photo-generated electron-hole transition. Therefore, the layer with the highest roughness exponent (2α = 0.48 ± 0.03), which means the smoother microscopic surface and better interfacial contact with the electrolyte, exhibited the best PEC activity.


Assuntos
Elétrons , Molibdênio , Compostos de Estanho , Software , Eletrólitos
17.
Chemosphere ; 335: 139133, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37290509

RESUMO

Sensing of cadmium (Cd) and lead (Pb) in environmental samples is crucial for identifying potential health risks associated with exposure to these heavy metals as well as understanding the extent of heavy metal contamination in different environments and its impact on the ecosystem. The present study elucidates the development of a novel electrochemical sensor that can detect Cd (II) and Pb (II) ions simultaneously. This sensor is fabricated using reduced graphene oxide (rGO) and cobalt oxide nanocrystals (Co3O4 nanocrystals/rGO). The characterization of Co3O4 nanocrystals/rGO was done by using various analytical techniques. The incorporation of cobalt oxide nanocrystals with intense absorption properties results in an amplification of the electrochemical current generated on the surface of the sensor by heavy metals. This, when coupled with the unique properties of the GO layer, enables the identification of trace levels of Cd (II) and Pb (II) in the surrounding environment. The electrochemical testing parameters were meticulously optimized to obtain high sensitivity and selectivity. The Co3O4 nanocrystals/rGO sensor exhibited exceptional performance in detecting Cd (II) and Pb (II) within a concentration range of 0.1-450 ppb. Notably, the limits of detection (LOD) for Pb (II) and Cd (II) were found to be highly impressive at 0.034 ppb and 0.062 ppb, respectively. The Co3O4 nanocrystals/rGO sensor integrated with the SWASV method displayed notable resistance to interference and exhibited consistent reproducibility and stability. Therefore, the suggested sensor has the potential to serve as a technique for detecting both ions in aqueous samples using SWASV analysis.


Assuntos
Metais Pesados , Nanopartículas , Cádmio , Chumbo , Reprodutibilidade dos Testes , Ecossistema , Óxidos/química , Nanopartículas/química
18.
Chemosphere ; 332: 138815, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37146774

RESUMO

Pendimethalin (PND) is a herbicide that is regarded to be possibly carcinogenic to humans and toxic to the environment. Herein, we fabricated a highly sensitive DNA biosensor based on ZIF-8/Co/rGO/C3N4 nanohybrid modification of a screen-printed carbon electrode (SPCE) to monitor PND in real samples. The layer-by-layer fabrication pathway was conducted to construct ZIF-8/Co/rGO/C3N4/ds-DNA/SPCE biosensor. The physicochemical characterization techniques confirmed the successful synthesis of ZIF-8/Co/rGO/C3N4 hybrid nanocomposite, as well as the appropriate modification of the SPCE surface. The utilization of ZIF-8/Co/rGO/C3N4 nanohybrid as a modifier was analyzed using. The electrochemical impedance spectroscopy results showed that the modified SPCE exhibited significantly lowered charge transfer resistance due to the enhancement of its electrical conductivity and facilitation of the transfer of charged particles. The proposed biosensor successfully quantified PND in a wide concentration range of 0.01-35 µM, with a limit of detection (LOD) value of 8.0 nM. The PND monitoring capability of the fabricated biosensor in real samples including rice, wheat, tap, and river water samples was verified with a recovery range of 98.2-105.6%. Moreover, to predict the interaction sites of PND herbicide with DNA, the molecular docking study was performed between the PND molecule and two sequence DNA fragments and confirmed the experimental findings. This research sets the stage for developing highly sensitive DNA biosensors that will be used to monitor and quantify toxic herbicides in real samples by fusing the advantages of nanohybrid structures with crucial knowledge from a molecular docking investigation.


Assuntos
Técnicas Biossensoriais , Grafite , Herbicidas , Humanos , Carbono , Simulação de Acoplamento Molecular , Técnicas Eletroquímicas/métodos , DNA/química , Grafite/química , Eletrodos
19.
Chemosphere ; 301: 134701, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35472613

RESUMO

Herein, simultaneous determination of Tl (1) and Pb (II) has been carried out at the surface of a modified glassy carbon electrode with polydopamine functionalized multi-walled carbon nanotubes- BiNPs nanocomposite (BiNPs/MWCNTs-PDA/GC) using square-wave anodic stripping voltammetry (SWASV) technique. The morphologies, composition and, electrochemical properties of the BiNPs/MWCNTs-PDA/GC were characterized by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDX), electrochemical impedance spectroscopy (EIS) and, SWASV. The parameters affecting the stripping current response were investigated and optimized. The large specific area of MWCNTs and good electro-conductibility of BiNPs causes the BiNPs/MWCNTs-PDA/GC electrode to exhibit an excellent electro-catalytic effect with good separation peaks for Tl and Pb oxidation compared to bare GCE under the optimal conditions. The proposed sensor showed wide leaner ranges from 0.4-100 ppb and 100-400 ppb for Tl (I) and Pb (II). Low detection limits of 0.04 ppb for Tl (I) and 0.07 ppb for Pb (II) were achieved. The efficiency of the electrode after thirty days of storage in ambient conditions without using it and also with the ability to reuse for 16 days did not decrease significantly. In addition, the modified electrode with simple preparation method showed good reproducibility, and high selectivity for measuring target ions. The method was successfully implemented for the simultaneous determination of Tl (I) and Pb (II) in tap, mineral and waste water samples with acceptable recovery (from 99.1-103.2 for Tl (I) and 98.4-100.4 for Pb (II)).


Assuntos
Técnicas Eletroquímicas , Nanotubos de Carbono , Técnicas Eletroquímicas/métodos , Chumbo , Nanotubos de Carbono/química , Reprodutibilidade dos Testes , Tálio
20.
Chemosphere ; 291(Pt 3): 132928, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34800513

RESUMO

Drug efficiency can be considerably boosted while adverse effects can be reduced by precisely monitoring the concentration of anti-cancer drugs. Thus, one of the most important parameters for human health is the monitoring and detection of anticancer drugs during chemotherapy treatment. Herein, a glassy carbon electrode (GCE) was modified by Pt- and Pd-incorporated ZnO nanoparticles-decorated single-wall carbon nanotubes (Pt-Pd-ZnO/SWCNTs) nanocomposites, and ds-DNA (Calf Thymus) that was a biological recognition element, and it was aimed to be utilized as an ultrasensitive and effective electroanalytical biosensor for idarubicin (IDR) monitoring. Various physicochemical characterization techniques including transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy (EDS) were used to investigate the morphology and structure of the Pt-Pd-ZnO/SWCNTs nanocomposite, which was produced via straightforward chemical precipitation combined with the one-pot method. The layer-by-layer modification technique was implemented to fabricate the ds-DNA/Pt-Pd-ZnO/SWCNTs/GCE to be further utilized as a voltammetric sensor for sensitive monitoring of idarubicin in biological fluids and pharmaceutical substances. The electroanalytical method implemented to detect idarubicin was based to detect the ds-DNA's guanine base signal on the surface of the modified electrode in the absence and presence of the anticancer drug. The results explicated that the developed biosensor performed well in determining idarubicin in concentrations ranging from 1.0 nM to 65 µM, with a detection limit of 0.8 nM. The idarubicin detection ability of the modified electrode in real samples was evaluated, and the recovery data was acquired in the range of 98.0% and 104.75%. In the final step, the preferential intercalative binding mode of idarubicin drug with ds-DNA was approved by molecular docking study. This study paves the way for engineering highly sensitive DNA biosensors to be employed in the monitoring of anticancer drugs by combining the benefits of nanocomposites and valuable information of a molecular docking study.


Assuntos
Técnicas Biossensoriais , Nanocompostos , Nanotubos de Carbono , DNA , Técnicas Eletroquímicas , Eletrodos , Guanina , Humanos , Idarubicina , Limite de Detecção , Simulação de Acoplamento Molecular
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