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In this work, a simple and sensitive electrochemical method was developed to determine ethyl violet (EV) dye in aqueous systems by using square wave anodic stripping voltammetry (SWASV) employing a glassy carbon electrode modified with acidic-functionalized carbon nanotubes (COOH

This study reports the synthesis, characterization, and mercuric ion detection ability of novel tribenzamides having flexible and rigid moieties.

The development of an efficient, selective, and highly sensitive electrochemical sensor for the simultaneous analysis of multiple drugs is a tough challenge. Herein, we report an applied electroche...

The development of a proficient and ultra-high sensitive functionalized electrode for accurate analysis of drugs is a long-standing challenge. Herein, we report an electrochemical nanocomposite scaffold, comprising of silver nanoparticles integrated with functionalized carbon nanotubes (COOH-CNTs/Ag/NH2-CNTs) for the simultaneous quantification of two widely used amlodipine (AM) and atorvastatin (AT) drugs. The sandwiched nanocomposite materials were thoroughly characterized morphologically and structurally. The nanocomposite COOH-CNTs/Ag/NH2-CNTs immobilized over glassy carbon electrode catalyzed electron transfer reactions at the electrode–electrolyte interface and facilitated detection of targeted drugs, as revealed by the significant decrease in oxidation potentials at 879 mV and 1040 mV and improved current signals. Electrochemical characterization and testing show that the functionalized porous architecture with a large effective surface area is a promising scaffold for the sensing of a binary mixture of AM and AT with limits of detection in the femtomolar range (77.6 fM, and 83.2 fM, respectively). Besides, the specificity, stability, and reliability of the electrochemical sensing platform in simple and complex biological and pharmaceutical samples with high percentage recoveries highlight its scope for practical applications. Computational studies supported the experimental outcomes and offered insights about the role of modifier in facilitating electron transfer between transducer and analytes.

In this study, we report highly stable photoactive quaternary metal chalcogenide Cu2ZnSnS4 nanocrystals synthesis from low cost, ecofriendly, non-toxic and earth-abundant elements for photovoltaic devices. Their electro-optical properties such as, tunable band gap, high-absorption coefficient and wide absorption window make them highly suitable materials to be utilized as absorber layer and counter electrode in various types of solar cells. For this purpose, first we synthesized Cu2ZnSnS4 nanocrystals by colloidal, co-precipitation, wet chemical and hydrothermal methods using stabilizing agents under variable reaction conditions. Afterwards, hydrothermal method was employed to synthesize nanocrystals of Cu2CoSnS4, Cu2FeSnS4, Cu2SrSnS4 and Cu2NiSnS4 by replacing Zn with Co, Fe, Sr and Ni metals. The UV–Vis absorption spectra indicate the nanocrystals can absorb entire visible region of electromagnetic radiation and their band gaps range from 1.5 to 1.7 eV. The X-ray diffraction (XRD) patterns confirm the formation of kieserite phase of all nanocrystals with a crystallite size of approximately 6–10 nm. These nanocrystals are coated on surface of the synthesized ZnO nanoparticles to study their application as absorbing layer in quantum dots-sensitized solar cells (QDSSCs). Moreover, they were adsorbed on ITO substrate to study their utilization as counter electrode of dye-sensitized solar cells (DSSCs). The solar cells exhibit efficiencies of 1.2–1.8%, which prove the synthesized nanocrystals can perform excellent role as light absorber and counter electrode in any kind of solar cell device.

Phenolic pollutants are highly toxic and persistent in the environment. Their efficient detection is a pressing social demand. In this regard we introduce a novel ultrasensitive electroanalytical platform for the individual and synchronized detection of three phenolic isomers commonly known as hydroquinone (HQ), resorcinol (RC), and catechol (CC). The sensing device consists of a glassy carbon electrode (GCE) modified with functionalized carbon nanotubes (fCNTs) and gold–silver (Au–Ag NPs) bimetallic nanoparticles. The sandwiched scaffold represented as fCNTs/Au–Ag NPs/fCNTs/GCE efficiently senses HQ, RC, and CC with detection limits of 28.6 fM, 36.5 fM and 42.8 fM respectively. The designed sensor is more promising than reported sensors for phenolic toxins in the context of high sensitivity, selectivity, and rapid responsiveness. The designed sensor also shows the qualities of stability, reproducibility, reliability, and selective recognition capacity for target analytes in multiple real water samples. Moreover, computational calculations explain the function of the electrode modifier in facilitating charge transfer between the transducer and analytes.

in this study, hybrid nanocomposites of poly vinylidene fluoride (PVDF) matrix were synthesized to maximize the electroactive β-phase. PVDF/clay, PVDF/clay/PZT (lead zirconate titanate) and PVDF/PZT composites series with PZT loading of (0–40 %) were fabricated using melt casting technique. PVDF/clay/PZT composites parameters were optimized as a function of micro sized PZT filler concentrations and montmorillonite clay incorporated in the PVDF matrix with different surface modifications. As the reported literature on PVDF/PZT composites for enhancement of β-phase is rare, thus a possible spectrum of PVDF/PZT formulations containing different weight percentages of PZT powder (0, 10, 20, 30 and 40 wt. %) were developed and studied. All the composites were made by melt mixing and casted into flexible and homogeneous thin films. Presence of electroactive β-phase was confirmed by different characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC). The gradual but noteworthy increment in polar β-phase was observed by fixing the composition of PVDF and nanoclay but varying the concentration of PZT. Further, it was observed that the change of organic surface modifications in montmorillonite clay not only improved the dispersion of filler in PVDF matrix but also maximized the electroactive β-phase.

The signals at the electrode-solution interface of an electrochemical nanosensor may either be dynamic or static. For dynamic methods, such as amperometric-based nanosensors that measure current proportional to the concentration of the analyte, the electroactive center of the species transfers electrons through a redox reaction at the working electrode, while in static methods the potentiometric mode of operation is followed in which charged species are involved. Nanoparticles and semiconductors have been shown to enhance the catalytic properties of analytical reactions by decreasing the overpotential of the reaction and facilitating faster electron transfer reactions, even conferring reversibility to some reactions reported to be irreversible at the unmodified electrode surfaces. Because all analytes are not intrinsically capable of serving as redox partners in electrochemical reactions, so mediators are used in these devices for facilitating the electrochemical reaction of the analytes at the electrode surface. The current chapter presents an overview of nanomaterials that affect sensing performance. Due to the attractive properties of materials at nanoscale dimensions, medical and pharmaceutical nanotechnology has become one of the most fascinating research topics in the fabrication and development of nanobiosensors. The morphology, geometric shape, and structural dimensions of materials at the nanoscale provide several advantages, which significantly influence the transduction ability of nanomaterial-modified electrodes.

Substituents play a major role in influencing the reactivity and biological activity of aromatic compounds. Substituents affect the conductivity of molecular electronic and photoresponsive switches, light harvesting dye-sensitized solar cells and organic electroluminescent devices. A number of quantum mechanical methods corresponding to stabilization energy, charge of substituent active region, energy dispersive analysis, and molecular electrostatic potential help in the description of substituent effect in aromatic systems. In the present work we carried out computational studies for the estimation of chemical and structural properties of a chemical library of nine ortho substituted naphthoic acids. The chemical reactivity of the selected substituted naphthoic acids was assessed from a number of physicochemical properties such as total energy, HOMO-LUMO gap, chemical hardness, binding energy, ionization potential, electron affinity, electronegativity, electrochemical potential, global softness, electrophilicity and dipole moment. The effect of the electron-donor groups on conjugation of ortho substituted naphthoic acid was investigated by correlating the calculated rotational barriers of transition state of cis and trans ortho-substituted naphthoic acids to observe change in single bond length, double bond length, bond angle, dihedral angle, and rotational frequency of carboxylic group of substituted napthoic acids. The rotational barrier correlated with the geometric, atomic, molecular, and spectroscopic parameters. Moreover, quantitative structure–activity relationship (QSAR) analyses was performed and the obtained structural properties were linked with biological activities.

A novel tribenzamides derivative N-{4-[2-(1,3-Benzoxazolyl)]phenyl}-3,5-N,N′-bis(4-hexyloxybenzoyl)benzamide (BOC6), containing three amide groups, was successfully synthesized and characterized through multiple spectroscopy techniques. The ultrasensitive electrochemical platform was developed by fabrication of glassy carbon electrode (GCE) with synthesized multifunctional tribenzamide appended BOC6 for the removal of water pollutants. The performance of the engineered sensor was studied by its electrochemical characterization with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave anodic stripping voltammetry (SWASV). The modifier played a facilitating role between the GCE surface and the target metal ions by bringing analytes closer to transducer surface resulting in appearance of intense electrochemical signals. Under pre-defined optimized conditions of SWASV, the BOC6 modified electrode was able to attain distinct oxidative current signals of thallium, arsenic, and mercuric ions simultaneously in one voltammogram scan. The sharp electrochemical signal and peak potential shift of thallium (Tl), arsenic (As) and mercury (Hg) oxidation at −0.79 V, −0.06 V and 0.22 V respectively, versus reference electrode Ag/AgCl evidence the electrocatalytic role of BOC6/GCE as compared to bare GCE at −0.68 V, −0.01 V and 0.3 V, respectively. Moreover, it was found to sense femtomolar concentration of aforementioned toxic ions, much lower than the world health organization (WHO) and environmental protection agency (EPA) guidelines for drinking water [1]. The limit of detections (LODs) obtained on for Tl(I), As(III), and Hg(II) detection were 2.19 fM, 1.97 fM, and 2.52 fM, respectively. Conclusively, the designed electrode was portable, cost effective, resistant to the interference species, highly stable and gives repeatable and reproducible voltammograms of analytes via strong interactions with target ions even in real water samples.