A novel electrochemical biosensor for the detection of ethambutol

A glassy carbon electrode (GCE) has been fabricated with zinc oxide nanoparticles (ZnONPs) and reduced graphene oxide (RGO) immobilized with horseradish peroxidase enzyme (HRP) for the voltammetric determination of ethambutol. Electrochemical behaviour of ethambutol has been studied with cyclic voltammetry and differential pulse voltammetry. The HRP-ZnONPs-RGO-GCE exhibits high electrooxidation of ethambutol in phosphate buffer solution at pH 7.0 and the electrochemical signal is significantly enhanced. In addition, the proposed biosensor has been characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The HRP-ZnONPs-RGO-GCE shows an oxidation peak at –0.2 V with CV. Under the optimized conditions, the DPV technique gave good limit of detection and limit of quantification values of 0.0214 μM and 0.6713 μM respectively. The HRP-ZnONPs-RGO-GCE shows excellent background current stability and gives reliable performance with pharmaceutical samples in the terms of sensitivity, reproducibility and repeatability

Intermolecular interactions in binary mixtures of phosphonium based ionic liquid and propanoic acid

Thermophysical properties of binary systems containing trihexyltetradecylphosphonium chloride [P+14, 6, 6, 6] [Cl ̶ ] ionic liquid (IL) and propanoic acid (PA), have been investigated. Measurements of densities  and speeds of sound  have been made at p = 0.1 MPa and at varying temperatures ranging from 293.15 to 313.15 K. The computed excess properties which include excess molar volume , apparent molar volume ( , intermolecular free length (Lf), isentropic compressibility , apparent molar isentropic compressibility ( ) and deviation in isentropic compressibility  have been computed from the experimental data of densities and speeds of sound. Based on the calculated derived properties, it is evident that the investigated IL and PA exhibit strong interactions across the entire mole fraction composition. Good correlation has been achieved with the Redlich-Kister equation

An Enzyme-Induced Novel Biosensor for the Sensitive Electrochemical Determination of Isoniazid

In this present work, a glassy carbon electrode (GCE) was modified primarily with multiwalled carbon nanotubes (MWCNTs) and a composite of MWCNTs and titanium oxide nanoparticles (TiO2NPs). The enzyme horseradish peroxidase (HRP) was immobilized to enhance the sensing ability of GCE. The proposed biosensor was used for the sensitive determination of isoniazid (INZ) in various pharmaceutical samples. The electrochemical behaviour of the developed MWCNT-TiO2NPs-HRP-GCE biosensor was studied by using cyclic voltammetry (CV) and differential pulse voltammetric (DPV) techniques. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetry (TGA) and transmission electron microscopy (TEM) techniques were used to characterize the developed sensor. Phosphate buffer solution (PBS) with pH 7 was used as supporting electrolyte in the present investigation. The cyclic voltammetric results revealed that the increment of anodic peak currents for the enzyme-induced sensor was almost 8-fold greater than that of a bare GCE. The DPV technique exhibited good limit of detection and limit of quantification values, viz., 0.0335 μM and 0.1118 μM, respectively. Moreover, the developed sensor showed long-lasting stability and repeatability without any interferents. This strongly indicates that the fabricated sensor shows outstanding electrochemical performance towards INZ, with excellent selectivity and sensitivity. The developed sensor was successfully applied to pharmaceutical samples and gave good percentages of recoveries

A novel electrochemical biosensor for the detection of ethambutol

887-895A glassy carbon electrode (GCE) has been fabricated with zinc oxide nanoparticles (ZnONPs) and reduced graphene oxide (RGO) immobilized with horseradish peroxidase enzyme (HRP) for the voltammetric determination of ethambutol. Electrochemical behaviour of ethambutol has been studied with cyclic voltammetry and differential pulse voltammetry. The HRP-ZnONPs-RGO-GCE exhibits high electrooxidation of ethambutol in phosphate buffer solution at pH 7.0 and the electrochemical signal is significantly enhanced. In addition, the proposed biosensor has been characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The HRP-ZnONPs-RGO-GCE shows an oxidation peak at –0.2 V with CV. Under the optimized conditions, the DPV technique gave good limit of detection and limit of quantification values of 0.0214 μM and 0.6713 μM respectively. The HRP-ZnONPs-RGO-GCE shows excellent background current stability and gives reliable performance with pharmaceutical samples in the terms of sensitivity, reproducibility and repeatability

A lignin polymer nanocomposite based electrochemical sensor for the sensitive detection of chlorogenic acid in coffee samples

In this study, an innovative nanocomposite of multiwalled carbon nanotubes (MWCNTs), copper oxide nanoparticles (CuONPs) and lignin (LGN) polymer were successfully synthesized and used to modify the glassy carbon electrode for the determination of chlorogenic acid (CGA). Cyclic voltammetry (CV) emphasised a quasi-reversible, adsorption controlled and pH dependent electrode procedure. In cyclic voltammetry a pair of well distinct redox peaks of CGA were observed at the LGN-MWCNTs-CuONPs-GCE in 0.1 M phosphate buffer solution (PBS), at pH 2. The synthesized nanoparticles and nanocomposites were characterized by Fourier transformation infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and x-ray diffraction (XRD) analyses. Differential pulse voltammetry (DPV) was applied to the anodic peak and used for the quantitative detection of CGA. Under optimal conditions, the proposed sensor showed linear responses from 5 μM to 50 μM, the linear regression equation Ipa (μA) = 2.6074 C-5.1027 (R2 = 0.995), whilst the limit of detection (LOD) and limit of quantifications (LOQ) were found to be 0.0125 μM and 0.2631 μM respectively. The LGN-MWCNTs-CuONPs-GCE were applied to detect the CGA in real coffee samples with the recovery ranging from 97 to 106 %. The developed sensor was successfully applied for the analysis of CGA content in the coffee samples. In addition, electrophilic, nucleophilic reactions and chlorogenic acid docking studies were carried out to better understand the redox mechanisms and were supported by density functional theory calculations

Intermolecular interactions in binary mixtures of phosphonium based ionic liquid and propanoic acid

753-760Thermophysical properties of binary systems containing trihexyltetradecylphosphonium chloride [P+14, 6, 6, 6] [Cl ̶ ] ionic liquid (IL) and propanoic acid (PA), have been investigated. Measurements of densities (ρ) and speeds of sound (u) have been made at p = 0.1 MPa and at varying temperatures ranging from 293.15 to 313.15 K. The computed excess properties which include excess molar volume (V), apparent molar volume (Vφ), intermolecular free length (Lf), isentropic compressibility (ks), apparent molar isentropic compressibility (Kφ) and deviation in isentropic compressibility (ks) have been computed from the experimental data of densities and speeds of sound. Based on the calculated derived properties, it is evident that the investigated IL and PA exhibit strong interactions across the entire mole fraction composition. Good correlation has been achieved with the Redlich-Kister equation

OCEAN: The Open Computation Exchange and Arbitration Network, a market approach to meta computing

Rapid advancements in processor and networking technologies have led to the evolution of cluster and grid computing frameworks. These high-performance computing environments exploit geographically distributed, diverse resources with the goal of providing efficient computing solutions to all kinds of parallel and distributed applications. OCEAN (Open Computation Exchange and Arbitration Network) provides a scalable market-based infrastructure to such meta-computing frameworks. OCEAN aims to build a marketplace where resources like CPU time, associated memory usage and network bandwidth are the traded commodities. This paper explains the technical challenges faced in the design of OCEAN and discusses our proposed solution. To facilitate finding suitable resources for buyers, we developed efficient matching and evolution protocols for the peer-to-peer matching network. The architecture and various components of OCEAN are described in detail. We implemented OCEAN on Java and.NET platforms and describe results from our preliminary experiments. 1