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This work reports a highly sensitive electrochemical sensor for organophosphate pesticide (malathion) based on unique and attractive CuO nanostructures. The discussed nanostructures were synthesize ...

It is highly important to explore the influence of counter anions on the morphology in order to have a desired nanostructure with unique properties. Therefore, in this research work the influence of counter anions on the morphology of copper oxide (CuO) nanostructures is presented using copper chloride and copper acetate salts. A significant role of counter anions on the morphology of CuO nanostructures is observed. The hydrothermal method is used to carry out the synthesis of CuO nanomaterial. The prepared CuO nanostructures are characterized by scanning electron microscopy and X-ray diffraction techniques. The prepared CuO nanomaterial exhibits porous nature with thin nanowires and sponge like morphologies. The dopamine sensing application was carried for exploring the electrocatalytic properties of CuO nanostructures. The presented dopamine biosensor exhibited wide linear range for detection of dopamine from 5 to 40 µM with sensitivity of 12.8 µA mMź1 cmź2. The limit of detection and limit of quantification were estimated in order 0.11 and 0.38 µM respectively. The developed dopamine biosensor is highly sensitive, selective, stable and reproducible. The common interfering species such as glucose, ascorbic acid and uric acid showed negligible change in the current when same concentration of dopamine and these interfering species was used. The fabricated biosensor could be used for the determination of dopamine from real blood samples.

Due to the increasing energy consumption, designing efficient electrocatalysts for electrochemical water splitting is highly demanded. In this study, we provide a facile approach for the design and fabrication of efficient and stable electrocatalysts through wet chemical methods. The carbon material, obtained by the dehydration of sucrose sugar, provides high surface area for the deposition of NiO nanostructures and the resulting NiO/C catalysts show higher activity towards the OER in alkaline media. During the OER, a composite of NiO with 200 mg C can produce current densities of 10 and 20 mA cm−2 at a bias of 1.45 V and 1.47 V vs. RHE, respectively. Electrochemical impedance spectroscopy experiments showed the lowest charge transfer resistance and the highest double layer capacitance in the case of the NiO/C composite with 200 mg C. The presence of C for the deposition of NiO nanostructures increases the active centers and consequently a robust electrocatalytic activity is achieved. The obtained results in terms of the low overpotential and small Tafel slope of 55 mV dec−1 for non-precious catalysts are clear indications for the significant advancement in the field of electrocatalyst design for water splitting. This composite material based on NiO/C is simple and scalable for widespread use in various applications, especially in supercapacitors and lithium-ion batteries.

It is always demanded to prepare a nanostructured material with prominent functional properties for the development of a new generation of devices. This study is focused on the synthesis of heart/dumbbell-like CuO nanostructures using a low-temperature aqueous chemical growth method with vitamin B-12 as a soft template and growth directing agent. CuO nanostructures are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. CuO nanostructures are heart/dumbbell like in shape, exhibit high crystalline quality as demonstrated by XRD, and have no impurity as confirmed by XPS. Apparently, CuO material seems to be porous in structure, which can easily carry large amount of enzyme molecules, thus enhanced performance is shown for the determination of uric acid. The working linear range of the biosensor is 0.001 mM to 10 mM with a detection limit of 0.0005 mM and a sensitivity of 61.88 mV/decade. The presented uric acid biosensor is highly stable, repeatable, and reproducible. The analytical practicality of the proposed uric acid biosensor is also monitored. The fabrication methodology is inexpensive, simple, and scalable, which ensures the capitalization of the developed uric acid biosensor for commercialization. Also, CuO material can be used for various applications such as solar cells, lithium ion batteries, and supercapacitors. Funding Agencies|National Natural Science Foundation of China; Research Fund for International Young Scientists [21550110195]; Chinese Academy of Sciences Presidents International Fellowship Initiative [2015PM010]

Numerous potentiometric biosensors are fabricated via biocatalytic and bioaffinity-based biosensing mechanisms. Only few of them are useful and applicable to the biomedical application and analysis. The most of those sensing schemes are mainly related to the protein metabolism especially urea and creatinine. The emergence of nanoscience and nanotechnology in the biomedical applications has provided the solid platform for the development of sensitive and selective potentiometric biosensors as new generation analytical devices. Therefore, among the nanomaterials, metal oxides are of prime importance for the potentiometric analytical devices due to generation of strong potential signals and excellent biocompatibility with the proteins such as enzymes, antibodies, DNA, and biological cells. This book chapter is dedicated to the recent advancement in the development of potentiometric biosensors such as urea, uric acid, glucose, and cholesterol due to nanoscience from fundamental to advanced configuration approach of devices.

In this work, a low temperature aqueous chemical growth methodology was used for the fabrication of CuO nanostructures. The as-synthesised nanostructures were then elaborately characterised by number of analytical techniques such as scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The obtained nanostructures were observed to possess interlaced rice-shaped structural features with the length and width of individual rice determined to be in the range of 200---300 nm and 50---100 nm respectively. The unique nanostructures when utilised as electrode material exhibited excellent electro-catalytic potential towards oxidation of hydrazine in alkaline media. The excellent conductive of CuO added by the high surface area of obtained nanorice-like structures enabled development of highly sensitive (3087 µA mMź1 cmź2), selective and stable electrochemical sensor for hydrazine. In addition, the successfully application of the developed sensor in spiked tap, bottled and industrial water samples for the detection of hydrazine suggested its feasibility for practical environmental application.

This study presents the development of a highly selective and sensitive electrochemical sensor for the determination of melamine from aqueous environments. The sensor system is based on functionalised marigold-like CuO nanostructures fabricated using a controlled hydrothermal process, where the utilised succinic acid is considered to play a dual role as a functionalising and growth controlling agent (modifier). The fabricated nanostructures exhibit sharp and well-ordered structural features with dimensions (thickness) in the range of 10–50 nm. The sensor system exhibits strong linearity within the concentration range of 0.1 × 10−9 to 5.6 × 10−9 M and demonstrates an excellent limit of detection up to 0.1 × 10−10 M. The extreme selectivity and sensing capability of the developed sensor is attributed to the synergy of selective interaction between succinic acid and melamine moieties, and the high surface area of marigold-like CuO nanostructures. In addition to this, the developed sensor was also utilised for the determination of melamine from real milk samples collected from different regions of Hyderabad, Pakistan. The obtained excellent recoveries proved the feasibility of the sensor for real life applications. The sensor system offers an operative measure for detecting extremely low melamine content with high selectivity in food contents.

The present study authenticates the fabrication of nickel oxide porous shaped nanostructure by hydrothermal method. The novel and functionalized nickel oxide nanomaterial were visualized by using scanning electron microscopy (SEM) and X-ray diffraction techniques (XRD). NiO nanomaterial advertised sensitive, selective and attracted morphology for the development of peptone biosensor. Phenylalanine displays a soft template and growth directing agent for the developing of nickel oxide low dimension nanostructures. The nickel oxide nanomaterial together with protease possesses tremendous role towards the oxidation potential phenomena and transfer of anodic electro-catalytic current for the peptone. The generation of low potential electrochemical signals exhibited the determination of peptone by utilizing different electrochemical techniques for the given concentration ranging from 0.1 mM to 2.5 mM with the measured limit of detection about 0.002 mM with a sensitivity of 107200 μA/mMCm2. The well-defined and highly developed sensor system provides the standard platform for the fabrication and functioning of new devices that are helpful for the determination of many biological macromolecules. The presented peptone biosensor is highly selective, sensitive, and reproducible that could also be useful for the determination of peptone from various milk samples. Validerad;2018;Nivå 1;2018-02-12 (rokbeg)