A Novel Micellar Electrokinetic Chromatographic Method for Separation of Metal-DDTC Complexes

Micellar electrokinetic chromatography (MEKC) was examined for the separation and determination of Mo(VI), Cr(VI), Ni(II), Pd(II), and Co(III) as diethyl dithiocarbamate (DDTC) chelates. The separation was achieved from fused silica capillary (52 cm × 75 μm id) with effective length 40 cm, background electrolyte (BGE) borate buffer pH 9.1 (25 mM), CTAB 30% (100 mM), and 1% butanol in methanol (70 : 30 : 5 v/v/v) with applied voltage of −10 kV using reverse polarity. The photodiode array detection was achieved at 225 nm. The linear calibration for each of the element was obtained within 0.16–10 μg/mL with a limit of detection (LOD) 0.005–0.0167 μg/mL. The separation and determination was repeatable with relative standard deviation (RSD) within 2.4–3.3% (n = 4) in terms of migration time and peak height/peak area. The method was applied for the determination of Mo(VI) from potatoes and almond, Ni(II) from hydrogenated vegetable oil, and Co(III) from pharmaceutical preparations with RSD within 3.9%. The results obtained were checked by standard addition and rechecked by atomic absorption spectrometry

Cathodic Stripping Voltammetric Determination of Cefadroxil in Pharmaceutical Preparations and in Blood Serum

Abstract An analytical method has been developed using hanging mercury drop electrode (HMDE) for the quantitative determination of antibacterial drug cefadroxil (CFL) from pharmaceutical preparations and blood serum. Cathodic adsorptive stripping voltammetry was carried out in hydrochloric acid (0.1M): methanol (80: 20 v/v) and potassium chloride (0.1M) as supporting electrolyte. The reduction wave was obtained within -700 to -800 mV. Linear calibration curve was within 1-50µg/mL with detection limit of 0.1µg/mL of cefadroxil. Relative standard deviation for inter and intra day analysis of CFL was within 1-2%. The number of additives present in pharmaceutical preparations did not interfere the determination of cefadroxil. The analysis of pharmaceutical preparations and blood serum after chemotherapy with cefadroxil indicated relative standard deviation (RSD) within 0.8-1.2% and 2.6-3.8% respectively. The satisfactory results were obtained for quality control of cefadroxil in pharmaceutical preparations and in blood serum

Reversed-Phase Liquid Chromatographic Separation and Determination of Ni(II), Cu(II), Pd(II), and Ag(I) Using 2-Pyrrolecarboxaldehyde-4-phenylsemicarbazone as a Complexing Reagent

This paper reports the utilization of 2-pyrrolecarboxaldehyde-4-phenylsemicarbazone (PPS) as a complexing reagent for the simultaneous determination and separation of Ni(II), Cu(II), Pd(II), and Ag(I) by reversed-phase high-performance liquid chromatography with UV detector. A good separation was achieved using Microsorb C18 column (150 × 4.6 mm i.d.) with a mobile phase consisted of methanol : acetonitrile : water : sodium acetate (1 mM) (68 : 6.5 : 25 : 0.5 v/v/v/v) at a flow rate of 1 mL/min. The detection was performed at 280 nm. The linear calibration range was 2–10 μg/mL for all metal ions. The detection limits (S/N = 3) were 80 pg/mL for Ni(II), 0.8 ng/mL for Cu(II), 0.16 ng/mL for Pd(II), and 0.8 ng/mL for Ag(I). The applicability and the accuracy of the developed method were estimated by the analysis of Ni(II) in hydrogenated oil (ghee) samples and Pd(II) in palladium charcoal

A Robust, Enzyme-Free Glucose Sensor Based on Lysine-Assisted CuO Nanostructures

The production of a nanomaterial with enhanced and desirable electrocatalytic properties is of prime importance, and the commercialization of devices containing these materials is a challenging task. In this study, unique cupric oxide (CuO) nanostructures were synthesized using lysine as a soft template for the evolution of morphology via a rapid and boiled hydrothermal method. The morphology and structure of the synthesized CuO nanomaterial were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The prepared CuO nanostructures showed high potential for use in the electrocatalytic oxidation of glucose in an alkaline medium. The proposed enzyme-free glucose sensor demonstrated a robust response to glucose with a wide linear range and high sensitivity, selectivity, stability, and reproducibility. To explore its practical feasibility, the glucose content of serum samples was successfully determined using the enzyme-free sensor. An analytical recovery method was used to measure the actual glucose from the serum samples, and the results were satisfactory. Moreover, the presented glucose sensor has high chemical stability and can be reused for repetitive measurements. This study introduces an enzyme-free glucose sensor as an alternative tool for clinical glucose quantification

Synthesis of Heart/Dumbbell-Like CuO Functional Nanostructures for the Development of Uric Acid Biosensor

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]</p

Pharmacological assessment of Co3O4, CuO, NiO and ZnO nanoparticles via antibacterial, anti-biofilm and anti-quorum sensing activities

Infectious diseases have risen dramatically as a result of the resistance of many common antibiotics. Nanotechnology provides a new avenue of investigation for the development of antimicrobial agents that effectively combat infection. The combined effects of metal-based nanoparticles (NPs) are known to have intense antibacterial activities. However, a comprehensive analysis of some NPs regarding these activities is still unavailable. This study uses the aqueous chemical growth method to synthesize Co3O4, CuO, NiO and ZnO NPs. The prepared materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. The antibacterial activities of NPs were tested against Gram-positive and Gram-negative bacteria using the microdilution method, such as the minimum inhibitory concentration (MIC) method. The best MIC value among all the metal oxide NPs was 0.63 against Staphylococcus epidermidis ATCC12228 through ZnO NPs. The other metal oxide NPs also showed satisfactory MIC values against different test bacteria. In addition, the biofilm inhibition and antiquorum sensing activities of NPs were also examined. The present study presents a novel approach for the relative analysis of metal-based NPs in antimicrobial studies, demonstrating their potential for bacteria removal from water and wastewater. HIGHLIGHTS Metal oxide nanoparticles were synthesized using the chemical growth method.; The prepared materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques.; The antimicrobial activity was tested against Gram-positive and Gram-negative bacteria.

An advanced and efficient Co3O4/C nanocomposite for the oxygen evolution reaction in alkaline media

The design of efficient nonprecious catalysts for the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) is a necessary, but very challenging task to uplift the water-based economy. In this study, we developed a facile approach to produce porous carbon from the dehydration of sucrose and use it for the preparation of nanocomposites with cobalt oxide (Co3O4). The nanocomposites were studied by the powder X-ray diffraction and scanning electron microscopy techniques, and they exhibited the cubic phase of cobalt oxide and porous structure of carbon. The nanocomposites showed significant OER activity in alkaline media, and the current densities of 10 and 20 mA cm(-2) could be obtained at 1.49 and 1.51 V versus reversible hydrogen electrode (RHE), respectively. The impedance study confirms favorable OER activity on the surface of the prepared nanocomposites. The nanocomposite is cost-effective and can be capitalized in various energy storage technologies