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1.
A platform based on praseodymium doped dysprosium oxide-carbon nanofibers modified electrode was constructed for the simultaneous determination of SY and TAR. SEM, EDX and XRD techniques were utilized for characterizing the proposed material. The voltammetric behaviour and properties of SY and TAR were gradually improved at materials in order from CNFs to Dy2O3−CNFs and Pr6O11@Dy2O3−CNFs. The working range was found to be 1.0×10−9–3.5×10−8 M and 1.5×10−9–4.0×10−8 M for SY and TAR, respectively. The value of LOD was 3.12×10−10 M and 5.35×10−10 M for SY and TAR, respectively. The platform (Pr6O11@Dy2O3−CNFs/GCE) was successfully applied to the electroanalysis of samples. 相似文献
2.
This study presents a sensitive voltammetric determination of terbutaline (TER) on a platform based on carbon nanotubes (CNTs) and europium oxide nanoparticles (Eu2O3NPs) coated glassy carbon electrodes (GCEs). An ultrasonic bath was performed for the preparation of composite material. The material was characterized by energy dispersive X‐ray spectroscopy (EDX), X‐ray diffraction method (XRD) and scanning electron microscopy (SEM). The Eu2O3NPs/CNTs/GCE system was assessed for the oxidation of terbutaline (TER). A broad oxidation peak was appeared at 0.71 V using a bare GCE. However, the voltammetry of TER has been improved at a GCE coated with CNTs and a well‐defined anodic peak exhibited at 0.61 V. Furthermore, the nanoparticles of Eu2O3 and CNTs coated GCE has greatly improved the electrochemical behaviour of TER and a sharp peak was appeared at 0.59 V. Cyclic voltammetry at Eu2O3NPs/CNTs/GCE also reveals a high catalytic effect for the oxidation of TER with an oxidation peak that is distinctly enhanced compared to GCE and CNTs/GCE. Eu2O3 nanoparticles were utilized to enhance the surface area of GCE and then improve the sensitivity of the procedure. The response of TER was linear over a concentration range of 2.0×10?8 M ?9.5×10?6 M with an LOD of 3.7×10?9 M. Square wave voltammetric analysis of tablets by Eu2O3NPs/CNTs/GCE yielded a recovery of 99.2 % with an RSD% of 3.2. The modified electrode (EuO2NPs/CNTs/GCE) provides accuracy and precision to the analysis of samples. 相似文献
3.
《Electroanalysis》2017,29(4):1197-1204
Amperometric sensor for eugenol based on glassy carbon electrode (GCE) modified with CeO2 nanoparticles dispersed in surfactant was fabricated. The effect of surfactant nature (sodium dodecylsulfate, cetylpyridinium bromide (CPB) and Brij® 35) on eugenol voltammetric behaviour was tested. In comparison to CeO2‐H2O/GCE, CeO2‐CPB/GCE showed 2.8‐fold increased current and 70 mV cathodic shift of potential in the diffusion‐controlled irreversible electrooxidation. The electrodes were characterized with SEM and EIS. CeO2‐CPB/GCE showed significantly lower charge transfer resistance (2.6±0.3 kΩ vs. 20±1 kΩ for CeO2‐H2O/GCE and 173±9 kΩ for GCE). Under conditions of DPV, the sensor linear dynamic range is 0.075‐75.0 μM of eugenol with the limits of detection (LOD) and quantification (LOQ) of 19.1 and 63.8 nM, respectively. The sensor exhibited high sensitivity, selectivity, good reproducibility and fast response and was applied for the real samples analysis (essential oils and clove spices). The results obtained correspond well to the data of spectrophotometric method. 相似文献
4.
This work presents a sensitive voltammetric method for determination of the flavonoid baicalein by using a thermally reduced graphene oxide (TRGO) modified glassy carbon electrode (GCE) in 100 mM KCl‐10 mM sodium phosphate buffer solution (pH 7.40). The surface morphology and structure of TRGO investigated by atomic force microscopy, FT‐IR spectroscopy and Raman spectroscopy reveal that the TRGO prepared maintained as single or bilayer sheets and with significant edge‐plane‐like defect sites. The TRGO/GCE modified electrode shows more favorable electron transfer kinetics for potassium ferricyanide and potassium ferrocyanide probe molecules, which are important electroactive compounds, compared with bare GCE and GO/GCE electrodes. The electrochemical behaviors of baicalein at the TRGO/GCE were investigated by cyclic voltammetry, suggesting that the TRGO/GCE exhibits excellent electrocatalytic activity to baicalein. Under physiological conditions, the modified electrode showed linear voltammetric response from 10 nM to 10 µM for baicalein, with a detection limit of 6.0 nM. This work demonstrates that the graphene‐modified electrode is a promising tool for electrochemical determination of flavonoid drugs. 相似文献
5.
利用改进的Hummers法制备了氧化石墨烯(GO), 以葡萄糖为还原剂直接在GO表面沉积银纳米粒子(AgNPs)得到性能稳定的AgNPs/GO纳米复合材料;基于该纳米复合材料修饰电极构建了一种新型的2, 4, 6-三硝基苯酚(TNP)电化学传感器。采用原子力显微镜(AFM)、扫描电镜(SEM)、透射电镜(TEM)、紫外可见光谱(UV-Vis)和交流阻抗(EIS)等多种方法对纳米复合薄膜进行了表征;并研究了TNP在复合薄膜修饰电极上的电化学行为和动力学性质。结果表明, AgNPs/GO对TNP有较强的电催化活性, 在复合薄膜修饰电极出现一灵敏的氧化峰和3个还原峰;利用氧化峰可对TNP进行定量分析。同时整个电极过程明显不可逆, 电极反应受到吸附步骤控制;复合膜电极表面覆盖度为5.617×10-8 mol·cm-2, 在所研究电位下的速率常数为9.745×10-5 cm·s-1。在pH 6.8的磷酸缓冲液中, 当富集电位为-0.70 V, 富集时间为60 s;TNP氧化峰电流与其浓度在5.0×10-9~1.0×10-7 mol·L-1范围内成良好线性关系, 相关系数为0.995 8, 检出限可达1.0×10-9 mol·L-1。所制备的电化学传感器稳定性和选择性较好;用于实际水样中TNP的现场快速检测, 加标回收率在 97.6%~103.9%之间。 相似文献
6.
基于银纳米粒子/氧化石墨烯复合薄膜制备TNP电化学传感器 总被引:1,自引:0,他引:1
利用改进的Hummers法制备了氧化石墨烯(GO),以葡萄糖为还原剂直接在GO表面沉积银纳米粒子(AgNPs)得到性能稳定的AgNPs/GO纳米复合材料;基于该纳米复合材料修饰电极构建了一种新型的2,4,6-三硝基苯酚(TNP)电化学传感器。采用原子力显微镜(AFM)、扫描电镜(SEM)、透射电镜(TEM)、紫外可见光谱(UV-Vis)和交流阻抗(EIS)等多种方法对纳米复合薄膜进行了表征;并研究了TNP在复合薄膜修饰电极上的电化学行为和动力学性质。结果表明,AgNPs/GO对TNP有较强的电催化活性,在复合薄膜修饰电极出现一灵敏的氧化峰和3个还原峰;利用氧化峰可对TNP进行定量分析。同时整个电极过程明显不可逆,电极反应受到吸附步骤控制;复合膜电极表面覆盖度为5.617×10-8mol.cm-2,在所研究电位下的速率常数为9.745×10-5cm.s-1。在pH 6.8的磷酸缓冲液中,当富集电位为-0.70 V,富集时间为60 s;TNP氧化峰电流与其浓度在5.0×10-9~1.0×10-7mol.L-1范围内成良好线性关系,相关系数为0.995 8,检出限可达1.0×10-9mol.L-1。所制备的电化学传感器稳定性和选择性较好;用于实际水样中TNP的现场快速检测,加标回收率在97.6%~103.9%之间。 相似文献
7.
An electrochemical sensing platform based on composite material, consisting of molecularly imprinted polymer coated on graphene oxide (MIP-GO), was developed for selective and sensitive analysis of amoxicillin (AMOX). The MIP-GO composite, which was fabricated by sol-gel polymerization after removal of template molecule, was deposited as a thin film on glassy carbon electrode, and then was electrochemically characterized by cyclic voltammetry and differential pulse voltammetry. The linear response for the determination of AMOX was obtained in the concentration range from 5.0×10−10 to 9.1×10−7 M under the most proper conditions and the detection limit was found to be 2.94×10−10 M. 相似文献
8.
ükriye UlubayKarabiberolu 《Electroanalysis》2019,31(1):91-102
A highly sensitive and selective chemical sensor was prepared based on metallic copper‐copper oxides and zinc oxide decorated graphene oxide modified glassy carbon electrode (Cu?Zn/GO/GCE) through an easily electrochemical method for the quantification of bisphenol A (BPA). The composite electrode was characterized via scanning electron microscopy (SEM), X‐Ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of BPA in Britton‐Robinson (BR) buffer solution (pH 7.1) was examined using cyclic voltammetry (CV). Under optimized conditions, the square wave voltammetry (SWV) response of Cu?Zn/GO/GCE towards BPA indicates two linear relationships within concentrations (3.0 nmol L?1?0.1 μmol L?1 and 0.35 μmol L?1?20.0 μmol L?) and has a low detection limit (0.88 nmol L?1). The proposed electrochemical sensor based on Cu?Zn/GO/GCE is both time and cost effective, has good reproducibility, high selectivity as well as stability for BPA determination. The developed composite electrode was used to detect BPA in various samples including baby feeding bottle, pacifier, water bottle and food storage container and satisfactory results were obtained with high recoveries. 相似文献
9.
Highly sensitive voltammetric method for hesperidin determination is developed using glassy carbon electrode modified with SnO2 nanoparticles (SnO2 NPs) and surfactants. The highest oxidation currents of hesperidin are observed in the case of cationic 0.50 mM cetylpyridinium bromide (CPB). Parameters of hesperidin electrooxidation have been calculated. Adsorptive anodic differential pulse voltammetry (AdADPV) in phosphate buffer pH 7.0 after 120 s accumulation provides linear dynamic ranges of 0.10–10 and 10–75 μM with the detection limit of 0.077 μM. The selectivity of hesperidin response is proved in the presence of inorganic ions, saccharides, ascorbic acid and other natural phenolics. 相似文献
10.
《Electroanalysis》2003,15(9):773-778
The reversible redox process that melatonin presented on carbon paste electrodes was the basis of a sensitive methodology for the determination of this hormone. From all the processes presented by this hormone, this was never used before as the basis of voltammetric measurements for melatonin determination. Therefore, parameters that affected the cyclic voltammetric signal were studied. A limit of detection as low as 9×10?11 M was obtained when optimized alternating current voltammetry was employed. The reproducibility was excellent due to an adequate pretreatment of the solid electrode (RSD=2.7%, n=10). A comparison with methodologies that employ different electrochemical techniques from the point of view of their analytical characteristics was made. This methodology has proved to be suitable for the determination of melatonin in biological fluids. 相似文献
11.
Trevor J Davies Eleanor R Lowe Shelley J Wilkins Richard G Compton 《Chemphyschem》2005,6(7):1340-1347
The average size of inert particles is determined using a simple electrochemical procedure. Alumina particles are deposited on an edge-plane graphite electrode, and a cyclic voltammogram is recorded. The scan rate employed varies between 0.2 and 2 V s(-1). At these scan rates the diffusion layer thickness is greater than the size of the alumina particles, minimizing the influence of the particles' height on the observed voltammetry. The average size of the particles is determined via comparison of the experimental voltammograms with simulations. 相似文献
12.
Muhammad Saqib Elena V. Dorozhko Jiri Barek Vlastimil Vyskocil Elena I. Korotkova Anastasiia V. Shabalina 《Molecules (Basel, Switzerland)》2021,26(16)
Laser-reduced graphene oxide (LRGO) on a polyethylene terephthalate (PET) substrate was prepared in one step to obtain the LRGO grid electrode for sensitive carbaryl determination. The grid form results in a grid distribution of different electrochemically active zones affecting the electroactive substance diffusion towards the electrode surface and increasing the electrochemical sensitivity for carbaryl determination. Carbaryl is electrochemically irreversibly oxidized at the secondary amine moiety of the molecule with the loss of one proton and one electron in the pH range from 5 to 7 by linear scan voltammetry (LSV) on the LRGO grid electrode with a scan rate of 300 mV/s. Some interference of the juice matrix molecules does not significantly affect the LSV oxidation current of carbaryl on the LRGO grid electrode after adsorptive accumulation without applied potential. The LRGO grid electrode can be used for LSV determination of carbaryl in fruit juices in the concentration range from 0.25 to 128 mg/L with LOD of 0.1 mg/L. The fabrication of the LRGO grid electrode opens up possibilities for further inexpensive monitoring of carbaryl in other fruit juices and fruits 相似文献
13.
《Electroanalysis》2017,29(4):1038-1048
Novel insights into the strategy of highly precise, carbon‐based electrochemical sensors are presented by exploring the excellent properties of graphene oxide (GO) and multiwalled carbon nanotube composites (GO‐MWCNTs/CPE) for the sensitive determination of tramadol hydrochloride (TRH). Cyclic voltammetry, differential pulse voltammetry, chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) scanning electron microscopy, and X‐ray diffraction (XRD) techniques were used to characterize the properties of the sensor. The linear response obtained for TRH using the GO‐MWCNTs/CPE was found to be over the range of 2.0x10−9 to 1.1x10−3 M with a good linearity and high correlation (0.9996). The limits of detection and quantification were found to be 1.50x10−10 M and 4.99 x 10−10 M, respectively. The proposed sensor was applied for determination of TRH in the presence of presence of co‐formulated drugs ketorolac tromethamine (KTM) and paracetamol (PAR). The sensor was shown to successfully apply to the determination of TRH in plasma as real samples. Satisfactory recoveries of TRH from samples clearly revealed that the proposed sensor can be applied into clinical analysis, quality control and a routine determination of drugs in pharmaceutical formulations. 相似文献
14.
Manganese Oxide Nanoparticles/Reduced Graphene Oxide as Novel Electrochemical Platform for Immobilization of FAD and its Application as Highly Sensitive Persulfate Sensor
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In this study, manganese oxide nanoparticles/reduced graphene oxide(MnOxNPs/rGO) was used as support for strong immobilization of flavin adenine dinucleotide(FAD). A thin film of rGO cast on the electrode surface, followed by performing electrodeposition of MnOxNPs at applied constant potential of +1.4 V vs. Ag/AgCl for 200 s. Finally, FAD was electrodeposited onto the rGO/MnOxNPs film by potential cycling between 1.0 to ?1.0 V in solution containing 1 mg ml?1 FAD. Electrochemical properties and catalytic activity of GCE/rGO‐MnOxNPs/FAD toward persulfate (S2O82?) reduction was investigated. Under optimized condition, the concentration calibration range, detection limit, and sensitivity were 0.1 μM–2 mM, 90 nM and 125.8 nA/μM, respectively, using hydrodynamic amperometry technique. 相似文献
15.
Dr. Ivana Šišoláková Jana Hovancová Frederika Chovancová Prof. Renáta Oriňaková Dr. Iveta Maskaľová Prof. Andrej Oriňak Prof. Jozef Radoňak 《Electroanalysis》2021,33(3):627-634
Screen printed carbon electrodes (SPCEs) modified by a combination of chitosan, multi walled carbon nanotubes (MWCNTs) and zinc nanoparticles (ZnNPs) were studied for the first time as a suitable candidate for non-enzymatic insulin determination. In an effort to find the most suitable modification for electrochemical insulin determination, the stability, analytical characteristics, and selectivity were determined. The results confirmed that the ZnNPs/chitosan-MWCNTs prepared with the Zn deposition time of 45 s displayed the best electrocatalytic activity towards insulin oxidation in a wide linear concentration range (0.5 μM to 5 μM), with low limit of detection and high sensitivity. 相似文献
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18.
《Electroanalysis》2018,30(9):2185-2194
The synthesis of novel nanocomposites with great sensing enhancement has played an important role in analytical chemistry, especially in the electrochemical detection of drug molecules. In this work, we report a wet chemical method for the preparation of a gold nanoparticle coated β‐cyclodextrin functionalized reduced graphene oxide nanocomposite. A number of different analytical techniques including ultraviolet‐visible spectroscopy, fourier transform infrared spectroscopy, scanning electron microscope and energy dispersive X‐ray spectroscopy were employed to characterize the as‐synthesized nanocomposite. With excellent electrocatalytic properties and high supramolecular recognition ability, the as‐synthesized nanocomposite was used to modify a glassy carbon electrode surface for the sensitive determination of ciprofloxacin using voltammetric technique. The current response of ciprofloxacin on the nanocomposite modified electrode was greatly enhanced compared to that on the bare and other modified electrodes. Using differential pulse voltammetry, the oxidation peak currents increased linearly with the ciprofloxacin concentrations in the range between 0.01 to 120 μM with a detection limit of 2.7 nM. The electrochemical testing results showed good stability and reproducibility. Therefore, the nanocomposite could be a potential candidate for the development of electrochemical sensors for sensitive and selective determination of ciprofloxacin or similar drugs in the future. 相似文献
19.
《Electroanalysis》2017,29(10):2401-2409
Copper nanoparticles (nano‐Cu) were electrodeposited on the surface of glassy carbon electrode (GCE) potentiostatically at −0.6 V vs. Ag/AgCl for 60 s. The developed nano‐copper modified glassy carbon electrode (nano‐Cu/GCE) was optimized and utilized for electrochemical assay of chemical oxygen demand (COD) using glycine as a standard. The surface morphology and chemical composition of nano‐Cu/GCE were investigated using scanning electron microscope (SEM) and energy dispersive X‐ray spectrometer (EDX), respectively. The electrochemical behavior was investigated using linear sweep voltammetry (LSV) which is characterized by a remarkable anodic peak at ∼0.6 V, compared to bare GCE. This indicates that nano‐Cu enhances significantly the electrochemical oxidation of glycine. The effect of different deposition parameters, such as Cu2+ concentration, deposition potential, deposition time, pH, and scan rate on the response of the developed sensor were investigated. The optimized nano‐Cu/GCE based COD sensor exhibited a linear range of 15 to 629.3 ppm, and a lower limit of detection (LOD) of 1.7 ppm (S/N=3). This developed method exhibited high tolerance level to chloride ion (0.35 M chloride ion has minimal influence). The analytical utility of the prepared COD sensor was demonstrated by investigating the COD recovery (99.8±4.3) and the assay of COD in different water samples. The results obtained were verified using the standard dichromate method. 相似文献
20.
《Electroanalysis》2017,29(2):602-608
Pt−Au nanoclusters decorated on the surface of reduced graphene oxide (rGO/Pt−Au) was facilely prepared by one‐pot electrochemical reduction. The morphology and composition of rGO/Pt−Au composites had been characterized by scanning electron microscopy (SEM) coupled with energy‐dispersive X‐ray spectrometry (EDX), fourier transform‐infrared spectroscopy (FT‐IR) and electrochemical methods. Ofloxacin is a member of synthetic quinolones which has been widely used for the treatment of common diseases in humans and animals. The performance of the rGO/Pt−Au nanocomposite toward the oxidation of ofloxacin was compared with the other similar nanostructures like rGO/Pt and rGO/Au. In the optimized conditions, two linear calibration curves were obtained, from 0.08 to 10 μM and 10 to 100 μM ofloxacin. A detection limit of 0.05 μM ofloxacin was observed at pH 5.7 for the GCE/rGO/Pt−Au. The proposed sensor was successfully applied to determine ofloxacin in tablets and human urine samples and the results were satisfactory. 相似文献