RESUMO
Abstract Lipoprotein monitoring is desirable in the management of medical conditions such as atherosclerotic cardiovascular disease and coronary artery disease, in which controlling the concentration of these chylomicrons is crucial. Current clinical methods are complex and present poor reproducibility between laboratories. For these reasons, recent guidelines discard the assessment of low-density lipoprotein cholesterol (LDL-C) as a routine analysis during lipid-lowering therapies. Concerning the importance of monitoring this parameter, the authors present an electrochemical immunosensor constructed from a simple and easy-to-reproduce platform that allows detecting and quantifying LDL nanoparticles directly from human serum samples. The performance of the biosensor was studied by scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The biosensing platform displays good stability and linearity between 30 mg dL-1 and 135 mg dL-1 with a detection limit of 20 mg dL-1. The proposed biosensor can be easily employed for monitoring LDL concentration in clinical treatments.
Assuntos
Transição de Fase , Lipoproteínas LDL/análise , Microscopia Eletrônica de Varredura/métodos , Eletroquímica/instrumentação , Espectroscopia Dielétrica/métodos , Hipercolesterolemia/classificaçãoRESUMO
In recent years, a lot of new detection techniques for circulating tumor cells (CTCs) have been developed. Among them, electrochemical sensing technology has gradually developed because of its advantages of good selectivity, high sensitivity, low cost and rapid detection. Especially in the latest decade, the field of electrochemical biosensing has witnessed great progress, thanks to the merging of biosensing research area with nanotechnology, immunotechnology, nucleic acid technology, and microfluidic technology. In this review, the recent progress for the detection of CTCs according to the principle of detection was summarized and how they can contribute to the enhanced performance of such biosensors was explained. The latest electrode construction strategies such as rolling circle amplification reaction, DNA walker and microfluidic technology and their advantages were also introduced emphatically. Moreover, the main reasonswhy the existing biosensors have not been widely used clinically and the next research points were clearly put forward.
Assuntos
Eletroquímica/instrumentação , Biópsia Líquida/métodos , Células Neoplásicas Circulantes/patologia , HumanosRESUMO
Atomic layer deposition (ALD) is a promising method for preparing nanomaterials. The thickness and uniformity of nanomaterials can be precisely controlled. Hence, the uniform Ni nanoparticles (Ni NPs) deposited on reduced graphene oxide (rGO) by ALD and got the optimal combination interface. The morphology, structure, and electrochemical behavior of Ni NPs-rGO nanocomposite are investigated. By experiment results, the Ni NPs could occupy some active surface of rGO, resulting in high conductivity and large specific surface area of Ni NPs-rGO nanocomposite. The Ni NPs-rGO nanocomposite exhibits high electrocatalytic activity for serotonin and speeds up the electron transfer between the surface of the electrode and the solution. Therefore, the sensor is prepared by Ni NPs-rGO nanocomposite modified glassy carbon electrode (GCE) and used to sensitive detection of serotonin. By differential pulse voltammetric, the Ni NPs-rGO/GCE enhanced the current responses and showed a wide linear range of 0.02-2 µM with a low detection of 0.01 µM for serotonin (S/N = 3). The Ni NPs-rGO/GCE exhibited good stability, selectivity, and anti-interference ability that can be used for real sample detection. According to these results, the Ni NPs-rGO nanocompositeis successfully prepared by ALD. The properties of Ni NPs-rGO nanocomposite make it an attractive material for potential applications in sensors and catalysis.
Assuntos
Eletroquímica/instrumentação , Grafite/química , Níquel/química , Serotonina/análise , Nanopartículas Metálicas/química , OxirreduçãoRESUMO
A glassy carbon electrode chemically modified with a carbon black coating is proposed here for the rapid and portable determination of cannabidiol (CBD) in a commercial Cannabis seed oil and in fibre-type Cannabis sativa L. leaves. The mechanism of CBD oxidation was studied in relation to simpler phenyl derivatives bearing the same electroactive group, namely resorcinol and 2-methylresorcinol. These molecules also allowed us to determine the best conditions for the electrochemical detection of CBD, as to the pH value and to the best solvent mixture to use. Carbon black was chosen among nanostructured carbon-based materials owing to its outstanding features as an electrode modifier for analyte detection. The performance of the modified electrode was determined by flow injection analyses of standard solutions of CBD, obtaining a linear correlation between the oxidation current and the analyte concentration; the sensor response is characterised by suitable repeatability and reproducibility. The analysis of commercial products by the standard addition method allowed us to ascertain the accuracy of the sensor for the detection of CBD in real samples.
Assuntos
Canabidiol/análise , Eletroquímica/instrumentação , Extratos Vegetais/química , Fuligem/química , Verduras/química , Canabidiol/química , Folhas de Planta/química , Água/químicaRESUMO
The present work is aimed at improving the adhesion of nanomaterials at the interface of solid state working electrodes. Towards this, herein, an efficient method has been proposed that requires the electrode interface to be decorated with an optimally thin layer of Nafion. This selectively permeable layer ensures the stability of the sensor interface, without hampering the transport of biomolecules and electrons. As a case study, here, electrospun Cerium oxide nanofiber (CeNF) modified Glassy carbon electrodes (GCE) have been used as the sensing interface, and stability and performance of the GCE/CeNF/Nafion interface is evaluated using analytical electrochemistry. The CeNF is synthesized via electrospinning and is characterized using X-ray diffraction spectroscopy, Thermal gravimetry, Fourier transform infrared spectroscopy, and Field emission scanning electron microscopy. Further, detection of sepsis specific biomarker TNF-α from spiked buffer samples is demonstrated, as a case study, towards evaluating the effect of Nafion on the interfacial sensitivity. The achieved LOD of GCE/CeNF and GCE/CeNF/Nafion for TNF-α detection were 2.8 fg/mL and 1.2 fg/mL, respectively. A comparative analysis between the Electrochemical impedance spectroscopic (EIS) results of the GCE/CeNF and the GCE/CeNF/Nafion interfaces confirms the improvement in stability, without affecting the sensitivity and the limiting detection.
Assuntos
Cério/química , Eletroquímica/instrumentação , Polímeros de Fluorcarboneto/química , Nanofibras/química , Fator de Necrose Tumoral alfa/análise , Carbono/química , Eletrodos , Limite de DetecçãoRESUMO
Hexestrol is a non-steroidal estrogen which causes carcinogenic effects in animals. It is therefore important to develop sensitive and selective test methods for its early detection. Herein, we report the development of an electrochemical sensor to detect hexestrol in ultralow concentrations. In order to devise a simple and cost-effective hexestrol sensing electrode, attention is paid to the development of biomass-derived porous carbon (PCB) with large surface area and suitable porosity to immobilize ruthenium oxide nanoparticles (RuO2 NPs, 3-4 nm). The leftover Citrus limetta pulp is chosen as waste biomass since it has N and O based chemical species. Structural, morphological and compositional analysis of PCB and RuO2@PCB revealed well-dispersed RuO2 NPs over the PCB surface. High loading (5.27 at%) of Ru content is achieved due to the large surface area of PCB. Cyclic voltammetry, chronoamperometry and differential pulse voltammetry results suggest that the RuO2@PCB/ITO electrode is capable of detecting hexestrol concentration (in the range of 1 × 10-7-2 × 10-5 M). The practical application of hexestrol detection in milk samples demonstrates the recovery from 96.28 to 101%.
Assuntos
Carbono/química , Citrus/química , Eletroquímica/instrumentação , Hexestrol/análise , Nanopartículas/química , Compostos de Rutênio/química , Biomassa , Análise Custo-Benefício , Eletroquímica/economia , Eletrodos , Hexestrol/química , Porosidade , Propriedades de SuperfícieRESUMO
The innovation of novel and proficient nanostructured materials for the precise level determination of pharmaceuticals in biological fluids is quite crucial to the researchers. With this in mind, we synthesized iron molybdate nanoplates (Fe2(MoO4)3; FeMo NPs) via simple ultrasonic-assisted technique (70 kHz with a power of 100 W). The FeMo NPs were used as the efficient electrocatalyst for electrochemical oxidation of first-generation antihistamine drug- Promethazine hydrochloride (PMH). The as-synthesized FeMo NPs were characterized and confirmed by various characterization techniques such as XRD, Raman, FT-IR, FE-SEM, EDX and Elemental mapping analysis and electron impedance spectroscopy (EIS). In addition, the electrochemical characteristic features of FeMo NPs were scrutinized by electrochemical techniques like cyclic voltammetry (CV) and differential pulse voltammetry technique (DPV). Interestingly, the developed FeMo NPs modified glassy carbon electrode (FeMo NPs/GCE) discloses higher peak current with lesser anodic potential on comparing to bare GCE including wider linear range (0.01-68.65 µM), lower detection limit (0.01 µM) and greater sensitivity (0.97 µAµM-1cm-2). Moreover, the as-synthesized FeMo NPs applied for selectivity, reproducibility, repeatability and storage ability to investigate the practical viability. In the presence of interfering species like cationic, anionic and biological samples, the oxidation peak current response doesn't cause any variation results disclose good selectivity towards the detection of PMH. Additionally, the practical feasibility of the FeMo NPs/GCE was tested by real samples like, commercial tablet (Phenergan 25 mg Tablets) and lake water samples which give satisfactory recovery results. All the above consequences made clear that the proposed sensor FeMo NPs/GCE exhibits excellent electrochemical behavior for electrochemical determination towards oxidation of antihistamine drug PMH.
Assuntos
Carbono/química , Eletroquímica/instrumentação , Antagonistas dos Receptores Histamínicos/análise , Ferro/química , Molibdênio/química , Nanoestruturas/química , Prometazina/análise , Sonicação , Técnicas de Química Sintética , Eletrodos , Vidro/química , Antagonistas dos Receptores Histamínicos/sangue , Antagonistas dos Receptores Histamínicos/urina , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Prometazina/sangue , Prometazina/urina , TemperaturaRESUMO
Breast cancer is a heterogeneous disease, and it lacks special tumor markers. Exosomes, new noninvasive biomarkers, with the proteins on the exosome surface show potential for the diagnosis and prognosis of a tumor. However, assessing the variations of exosomal proteins still faces significant challenges. Herein, a magneto-mediated electrochemical sensor based on host-guest recognition has been developed for simultaneous analysis of breast cancer exosomal proteins. Magnetic beads (MB) modified with CD63 aptamer was first employed to capture exosomes. Silica nanoparticles (SiO2 NPs) was modified with MUC1, HER2, EpCAM, and CEA aptamers for specific exosomal proteins identification, respectively, and functionalized with N-(2-((2-aminoethyl)disulfanyl)ethyl) ferrocene carboxamide (FcNHSSNH2) as the signal molecule. The sandwich structure (MB-exosomes-SiO2 NPs probe) was separated by a magnet, and N-(2-mercaptoethyl) ferrocene carboxamide (FcNHSH) was released to the supernatant by the addition of reductants (dithiothreitol, DTT) that break the disulfide bond of FcNHSSNH2. FcNHSH and the graphene oxide-cucurbit [7](GO-CB[7]) modified screen-printed carbon electrode (SPCE) was employed to monitor the oxidation current signals. In this way, four tumor markers on different breast cancer cells (MCF-7, SK-BR-3, MDA-MB-231, and BT474) derived exosomes were sensitively detected. Furthermore, the present assay enabled accurate analysis of exosomes from breast cancer patients, suggesting the potential of exosome analysis in clinic diagnosis.
Assuntos
Neoplasias da Mama/patologia , Eletroquímica/instrumentação , Exossomos/metabolismo , Fenômenos Magnéticos , Proteínas de Neoplasias/metabolismo , Linhagem Celular Tumoral , Estudos de Viabilidade , Humanos , Microesferas , Nanopartículas/química , Dióxido de Silício/química , Fatores de TempoRESUMO
The ultrasound-assisted synthesis of a novel neodymium sesquioxide nanoparticles (Nd2O5 NPs) decorated graphene oxide (GO) nanocomposite under ultrasonic probe (Ultrasonic processor model-PR 1000; frequency-30â¯kHz; power of 100â¯W/cm2) has been reported. After then, SEM, TEM, XRD, EDX and electrochemical impedance spectroscopy characterized was analyzed using Nd2O5 NPs@GO nanomaterial. Furthermore, the nanomaterial modified GCE (glassy carbon electrode) shows excellent electrochemical sensing performance towards anti-cancer drug. Raloxifene is one of the important anti-cancer drug. Moreover, the fabricated electrochemical sensor has showed a wide linear range for raloxifene between 0.03 and 472.5⯵M and nanomolar detection limit (18.43â¯nM). In addition, the Nd2O5 NPs@GO modified sensor has been applied to the determination of raloxifene in human blood and urine samples.
Assuntos
Eletroquímica/instrumentação , Grafite/química , Limite de Detecção , Nanocompostos/química , Nanotecnologia , Cloridrato de Raloxifeno/análise , Ondas Ultrassônicas , Antineoplásicos/análise , Antineoplásicos/sangue , Antineoplásicos/química , Antineoplásicos/urina , Técnicas de Química Sintética , Eletrodos , Humanos , Cloridrato de Raloxifeno/sangue , Cloridrato de Raloxifeno/química , Cloridrato de Raloxifeno/urinaRESUMO
Fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes (CFMEs) is a versatile electrochemical technique to probe neurochemical dynamics in vivo. Progress in FSCV methodology continues to address analytical challenges arising from biological needs to measure low concentrations of neurotransmitters at specific sites. This review summarizes recent advances in FSCV method development in three areas: (1) waveform optimization, (2) electrode development, and (3) data analysis. First, FSCV waveform parameters such as holding potential, switching potential, and scan rate have been optimized to monitor new neurochemicals. The new waveform shapes introduce better selectivity toward specific molecules such as serotonin, histamine, hydrogen peroxide, octopamine, adenosine, guanosine, and neuropeptides. Second, CFMEs have been modified with nanomaterials such as carbon nanotubes or replaced with conducting polymers to enhance sensitivity, selectivity, and antifouling properties. Different geometries can be obtained by 3D-printing, manufacturing arrays, or fabricating carbon nanopipettes. Third, data analysis is important to sort through the thousands of CVs obtained. Recent developments in data analysis include preprocessing by digital filtering, principal components analysis for distinguishing analytes, and developing automated algorithms to detect peaks. Future challenges include multisite measurements, machine learning, and integration with other techniques. Advances in FSCV will accelerate research in neurochemistry to answer new biological questions about dynamics of signaling in the brain.
Assuntos
Eletroquímica/métodos , Análise de Dados , Eletroquímica/instrumentação , Microeletrodos , Fatores de TempoRESUMO
Lamellar MoS2 nanosheets were successfully prepared by hydrothermal synthesis using 1-(3-mercaptopropyl)-3-methyl-imidazolium bromine (MIMBr) ionic liquid as a sulfur source and a morphology control agent, and sodium molybdate as a molybdenum source. Gold nanoparticles were assembled on the surface of MoS2 nanosheets by the in situ reduction of chloroauric acid at low temperatures to successfully fabricate AuNP/2D-MoS2 nanocomposites, thus improving photoelectrochemical response. AuNP/2D-MoS2 nanocomposites were used as photoelectrically active materials modified onto a glassy carbon electrode surface to construct a photoelectrochemical (PEC) sensor. Then, using 1-(N-pyrrolpropyl)-3-methyl-imidazolium bromine (PMIMBr) ionic liquid as a functional monomer and pro-gastrin-releasing peptide (Pro-GRP) as a template, a molecularly imprinted polymerized ionic liquid film was electrochemically deposited on an AuNP/2D-MoS2/GCE surface. Upon removing the templates, a molecularly imprinted photoelectrochemical sensor was constructed for the sensing of a tumor marker, pro-gastrin-releasing peptide. Experimental conditions including ascorbic acid concentration, polymerization conditions, incubation time, and pH value of the incubation solution have been optimized. Under the optimized conditions, the molecularly imprinted photoelectrochemical sensor can specifically detect the target protein Pro-GRP in the range of 0.02 ng mL-1-5 ng mL-1 with a detection limit of 0.0032 ng mL-1 (S/N = 3). The practicability of this photoelectrochemical sensor was demonstrated by accurately determining Pro-GRP in human serum samples.
Assuntos
Dissulfetos/química , Eletroquímica/instrumentação , Ouro/química , Nanopartículas Metálicas/química , Impressão Molecular , Molibdênio/química , Processos Fotoquímicos , Precursores de Proteínas/análise , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Líquidos Iônicos/química , Limite de Detecção , Nanocompostos/química , Propriedades de SuperfícieRESUMO
A low-cost and disposable microcell was constructed with a screen-printed electrode for the non-enzymatic electrochemical determination of creatinine. The working electrode was modified with carbon black and maintained in contact with paper-adsorbed iron (III) ions. A small sample volume of 3⯵L was required for the device operation. Then, iron (III) ions were complexed in the presence of creatinine in a chemical step, followed by an electrochemical reduction of non-complexed metallic ions in excess. Cyclic voltammetry and differential-pulse voltammetry experiments were employed for the electrochemical characterizations and analytical performance evaluation of the microcell. The working electrode modification with carbon black provided a significant increase of analytical signal. The sensor presented a linear response for creatinine concentrations ranging from 0.10 to 6.5â¯mmolâ¯L-1, with a limit of detection of 0.043â¯mmolâ¯L-1. Experiments for creatinine determination in real samples were successful performed through of standard recovery in urine.
Assuntos
Creatinina/análise , Eletroquímica/instrumentação , Análise em Microsséries/instrumentação , Impressão , Creatinina/química , Creatinina/urina , Eletrodos , Química Verde , Humanos , Ferro/química , Limite de Detecção , Fuligem/químicaRESUMO
Noncoding small RNAs, such as microRNAs, are becoming the biomarkers of choice for multiple diseases in clinical diagnostics. A dysregulation of these microRNAs can be associated with many different diseases, such as cancer, dementia, and cardiovascular conditions. The key for effective treatment is an accurate initial diagnosis at an early stage, improving the patient's survival chances. In this work, the first clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a-powered microfluidic, integrated electrochemical biosensor for the on-site detection of microRNAs is introduced. Through this unique combination, the quantification of the potential tumor markers microRNA miR-19b and miR-20a is realized without any nucleic acid amplification. With a readout time of 9 min and an overall process time of less than 4 h, a limit of detection of 10 pm is achieved, using a measuring volume of less than 0.6 µL. Furthermore, the feasibility of the biosensor platform to detect miR-19b in serum samples of children, suffering from brain cancer, is demonstrated. The validation of the obtained results with a standard quantitative real-time polymerase chain reaction method shows the ability of the electrochemical CRISPR-powered system to be a low-cost, easily scalable, and target amplification-free tool for nucleic acid based diagnostics.
Assuntos
Técnicas Biossensoriais/instrumentação , Proteínas Associadas a CRISPR/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Eletroquímica/instrumentação , Dispositivos Lab-On-A-Chip , MicroRNAs/análise , Sequência de Bases , Calibragem , MicroRNAs/genética , Técnicas de Amplificação de Ácido NucleicoRESUMO
This paper develops an efficient electrochemiluminescence (ECL) enhancement strategy on closed bipolar electrode for the detection of prostate specific antigen (PSA). We first synthesized a cyclometalated iridium(III) complex (pq)2Irbza with high ECL efficiency and used as ECL emitter in the anodic cell of BPE. While we introduced a Pt-tipped Au NRs and constructed a sandwich immune structure at the cathodic pole of BPE. Combined the signal amplification strategies of enzyme catalysis and the synergistic catalytic effect of bimetallic structure for the reduction of H2O2, the attached Pt-tipped Au NRs-GOx-Ab2 nanocomplex as both recognition probes and signal amplification units could mediate the ECL signals of (pq)2Irbza/tripropylamine (TPrA) on the anodes of BPE through faradaic reaction due to the charge neutrality of BPE. Therefore, a highly sensitive BPE-ECL sensor for detection of PSA with a detection limit of 0.72 pg/mL and a linear range from 1.0 pg/mL to 10 ng/mL was obtained. This work is expected to broaden the application of iridium complex and bimetallic nanocatalyst in biological detection and could be utilized to detect many other biological molecules.
Assuntos
Eletroquímica/instrumentação , Medições Luminescentes , Antígeno Prostático Específico/análise , Eletrodos , Irídio/química , Compostos Organometálicos/química , Propilaminas/química , Antígeno Prostático Específico/químicaRESUMO
To explore a novel and multi-layer based graphene oxide covered zinc oxide nanoflower (ZnO NFs@GOS) as a modified electrode materials by sonochemical technique (40â¯kHz, 300â¯W). Herein, novel nanocomposite is successfully characterized by various characterization analysis (FESEM, HRTEM, XRD, XPS and (EIS) electrochemical impedance spectroscopy) and employed as high sensitive modified electrode (ZnO NFs@GOS nanocomposite) for the electrochemical determination of biomarker. 8-hydroxy-2'-deoxyguanosine (8-HDG) is one of the important cancer and oxidative stress biomarker. The results demonstrated that the ZnO NFs@GOS modified SPCE reveal well-defined electro-oxidation peak at 0.36â¯V (vs. Ag/AgCl). The high sensitive properties of the optimized flower like modified electrode are because of the excellent synergistic effect of the ZnO flower and the graphene oxide nanosheets, as evidenced by a superior bio-sensing performance. The nanocomposite fabricated modified biosensor was facilitating the analysis of 8-HDG in the concentration ranges of 0.05-536.5⯵M with a low detection limit is 8.67â¯nM. The ZnO NFs@GOS modified sensor can also employed for the determination of 8-HDG in human urine samples, promising its application towards the quantification of cancer biomarker in biological samples.
Assuntos
8-Hidroxi-2'-Desoxiguanosina/urina , Dano ao DNA , Eletroquímica/instrumentação , Grafite/química , Ondas Ultrassônicas , Urinálise/instrumentação , Óxido de Zinco/química , 8-Hidroxi-2'-Desoxiguanosina/química , Biomarcadores/química , Biomarcadores/urina , Catálise , Eletrodos , Limite de DetecçãoRESUMO
Bisphenol A (BPA) is an endocrine-disrupting chemical which resembles structurally the hormone estrogen. Even a trace amount of BPA can bind estrogen receptors resulting in the inducement of reproductive disorders, cancers and problems related to sexual growth such as manliness in female and womanliness in male. So the determination of BPA in human and animal bodies is very essential. For this purpose, a new nanocomposite composed of ruthenium nanoparticles, polyaniline and graphitic carbon nitride (Ru0/PANI/g-C3N4) has been synthesized ultrasonically (40⯱â¯3â¯kHz, 200â¯W). A modification on glassy carbon electrode (GCE) with the nanocomposite detects BPA in human and animal urine samples with wide linear range (0.01-1.1⯵M) and the limit of detection is pico molar-level. The synthesized nanocomposite was characterized by Ultraviolet-Visible and Fourier Transform-Infra Red spectroscopies, thermo gravimetric analysis, transmission electron microscopy, X-ray diffraction study, energy dispersive X-ray analysis, and elemental mapping analysis. This sensing system is selective, stable and reusable, by which the detection of BPA in various physiological fluids is very much possible.
Assuntos
Compostos de Anilina/química , Compostos Benzidrílicos/urina , Eletroquímica/métodos , Limite de Detecção , Nanocompostos/química , Nitrilas/química , Fenóis/urina , Rutênio/química , Animais , Compostos Benzidrílicos/química , Técnicas de Química Sintética , Eletroquímica/instrumentação , Eletrodos , Disruptores Endócrinos/química , Disruptores Endócrinos/urina , Humanos , Nanopartículas Metálicas/química , Modelos Moleculares , Conformação Molecular , Nanotecnologia , Fenóis/químicaRESUMO
A solid-state electrochemiluminescence (ECL) sensor for the detection of reduced glutathione (GSH) based on a g-C3N4/SiO2 modified glass carbon electrode (GCE) has been developed in this research. The g-C3N4, which is employed as a luminophore, is simply prepared and exhibits an excellent ECL response. Mesoporous silica hollow spheres (SiO2) with a large specific surface area are introduced here to increase the loading amount of g-C3N4. Compared to a g-C3N4 modified GCE, the g-C3N4/SiO2 modified GCE displays a much higher ECL intensity. A high enhancement effect on the ECL intensity of g-C3N4/SiO2 modified GCE is obtained in the presence of GSH in the electrolyte. Moreover, the enhanced ECL intensity shows a good linear relationship to the GSH concentration in the range from 1.0 × 10-7 to 5.0 × 10-4 M, with a detection limit of 2.0 × 10-8 M (6.1 ng/mL). Besides, the ECL sensor exhibits a good anti-interference ability and has been successfully applied in the detection of GSH in commercial samples. The proposed sensor provides a promising platform for life science.
Assuntos
Eletroquímica/instrumentação , Glutationa/análise , Grafite/química , Medições Luminescentes/instrumentação , Nitrilas/química , Dióxido de Silício/química , Eletrodos , Vidro/química , Glutationa/químicaRESUMO
We report a facile and ultrasound assisted sonochemical synthesis of a Tungsten disulfide nanorods decorated nitrogen-doped reduced graphene oxide based nanocomposite. The WS2 NRs/N-rGOs nanocomposite was characterized by FESEM, HRTEM, XRD, XPS and electrochemical methods and its application towards the electrochemical detection of organo-arsenic drug (coccidiostat). The WS2 NRs/N-rGOs modified SPCE was used for the electrochemical reduction of roxarsone (ROX) and it showed superior electrocatalytic performance in terms of reduction peak current and shift in overpotential when compared to those of WS2 NRs/SPCE, N-rGOs/SPCE and based SPCE. The WS2 NRs/N-rGOs modified SPCE showed an excellent sensing ability towards ROX in nitrogen saturated phosphate buffer (PB) then the other controlled modified and unmodified electrodes. The WS2 NRs/N-rGOs/SPCE displays high sensitive response towards ROX and gives wide linearity in the range of 0.1-442.6⯵M ROX in neutral phosphate buffer (pH 7.0) and the sensitivity of the sensor is calculated as 14.733⯵A⯵M-1â¯cm-2. The WS2 NRs/N-rGOs nanocomposite modified sensor also exhibits valuable ability of anti-interference to electroactive analytes. Furthermore, the as-prepared WS2 NRs/N-rGOs/SPCE has been applied to the determination of ROX in biological and pharmaceutical samples.
Assuntos
Antibacterianos/análise , Eletroquímica/instrumentação , Grafite/química , Limite de Detecção , Nanotubos/química , Nitrogênio/química , Roxarsona/análise , Sulfetos/química , Compostos de Tungstênio/química , Antibacterianos/química , Catálise , Técnicas de Química Sintética , Eletrodos , Concentração de Íons de Hidrogênio , Cinética , Porosidade , Roxarsona/químicaRESUMO
Photocathodic methods in photoelectrochemical (PEC) analysis are based on the use of functional photocathodes. Heterojunction cathodes consisting of different kinds of semiconductors are being considered as favorite schemes when compared to the single-component ones. A semiconductor heterojunction between CuBi2O4 (CBO) and other semiconductors has not been exploited in PEC assays so far. Herein, CBO nanospheres were initially electrochemically deposited on a fluorine-doped tin oxide (FTO) conductive glass and then coupled to chemically deposited AgI nanoparticles to obtain an electrode of type AgI/CBO/FTO. It was applied as a cathode in the PEC detection of L-cysteine as a model analyte. The sensor can selectively detect L-cysteine, and it is assumed that this is due to the selective interaction between the L-cysteine and both copper and silver via the formation of Cu-S and Ag-S bonds. The photocurrent of the electrode increases linearly with the logarithm of the cysteine concentration in the range from 0.1 and 50 µM, and the detection limit is 0.1 µM. Graphical abstract Schematic presentation of the preparation of an AgI/CuBi2O4 (AgI/CBO) heterojunction on a fluorine-doped tin oxide (FTO) electrode and its application to the cathodic photoelectrochemical detection of L-cysteine.
Assuntos
Bismuto/química , Cisteína/análise , Eletroquímica/instrumentação , Flúor/química , Iodetos/química , Processos Fotoquímicos , Compostos de Prata/química , Compostos de Estanho/química , Cisteína/química , Eletrodos , Limite de Detecção , SemicondutoresRESUMO
Irreversible organ damage or even death frequently occurs when humans or animals unknowingly drink contaminated water. Therefore, in many countries drinking water is disinfected to ensure removal of harmful pathogens from drinking water. If upstream water treatment prior to disinfection is not adequate, disinfection byproducts (DBPs) can be formed. DBPs can exist as wide variety of compounds, but up until now, only several typical compounds have drinking water standards attributed to them. However, it is apparent that the range of DBPs present in water can comprise hundreds of compounds, some of which are at high enough concentrations to be toxic or potentially carcinogenic. Hence, it becomes increasingly significant and urgent to develop an accessible, affordable, and durable sensing platform for a broader range and more sensitive detection of DBPs. Compared with well-established laboratory detection techniques, electrochemical sensing has been identified as a promising alternative that will provide rapid, affordable, and sensitive DBP monitoring in remote water sources. Therefore, this Review covers current state-of-the-art development (within the past decade) in electrochemical sensing to detect organic DBPs in water, which covered three major aspects: (1) recognition mechanism, (2) electrodes with signal amplification, and (3) signal read-out techniques. Moreover, comprehensive quality assessments on electrochemical biosensors, including linear detection range, limit of detection (LoD) and recovery, have also been summarized.