pH Controlled Condition for Selective Simultaneous Determination of Nickel and Cobalt in Alloys by First Derivative Spectrophotometry

1-(2-Pyridylazo)-2-naphthol (PAN) has been used for the simultaneous determination of nickel and cobalt at trace levels. PAN complexes of nickel and cobalt in the pH 1.89 form red and green colored complexes, respectively which are soluble in aqueous Tween 80 micellar media. Under optimum conditions, calibration graphs for simultaneous determination by first derivative spectrophotometry were obtained. Zero crossing first derivative spectrophotometry at 641 and 580 nm was used for the simultaneous determination. The method is able to determine cobalt to nickel ratio 15:1 to 1:6 (Wt/Wt), accurately. Accuracy and reproducibility of the determination method on the known various amounts of cobalt and nickel in their binary mixtures were tested. Effects of diverse ions on the determination of cobalt and nickel to investigate selectivity of the method were also studied. The recommended procedure was applied to various nickel-cobalt alloys

A voltammetric sensor based on poly(eriochrome black T) modified glassy carbon electrode for the simultaneous determination of dihydroxybenzene isomers

An electrochemical sensor based on deposition of polymeric film by using electrochemical method on the surface of glassy carbon electrode was fabricated for simultaneous determination of dihydroxybenzene using differential pulse voltammetry (DPV). The sensor was constructed by simple modification of glassy carbon electrode (GCE) with a uniform electro-polymerized film of poly (eriochrome black T) (poly(EBT)). The electro-chemical behaviors of hydroquinone (HQ), catechol (CC) and resorcinol (RS) at the modified electrode were studied. The obtained peak current was linearly dependent on the HQ, CC, and RS concentrations in the range of 0.50-70.0 µM, 0.50-70.0 µM and 1.0-70.0 µM, respectively. The detection limits for HQ, CC and RS at the surface of poly(EBT)/GCE were 0.20 µM, 0.11 µM and 0.60 µM (3σ), respectively. In addition, simultaneous determination of dihydroxybenzene was evaluated in real sample of water with differential pulse voltammetry

(4,7-Diphenyl-1,10-phenanthroline-κ2 N,N′)diiodidomercury(II)

In the mol­ecule of the title compound, [HgI2(C24H16N2)], the HgII atom is four-coordinated in a distorted tetra­hedral configuration by two N atoms from the bidentate 4,7-diphenyl-1,10-phenanthroline and two iodide ligands. There is a π–π contact between the pyridine and phenyl rings [centroid-to-centroid distance = 4.2387 (4) Å]

Synthesis of Flower-like Ag-ZnO Nanostructure and its Application in the Photodegradation of Methyl Orange

Nanostructured Ag-ZnO materials were successfully synthesized by first producing a ZnO with flower-like morphology using a simple precipitation method, and then Ag nanoparticles were prepared directly on the surface by a facile photoreduction method. The materials were characterized by scanning and transmission electron microscopy (SEM and TEM), by X-ray diffractometry (XRD) and atomic absorption spectrometry (AAS). They were shown to be composed of metallic Ag particles dispersed on the surface of flower-like ZnO structures. Photocatalytic effect of Ag-ZnO on the photodegradation of methyl orange (MO) under UV irradiation was investigated in aqueous suspension. The effect of pH, Ag content, photodeposition time, concentration of the organic dye and presence of Mg2+, Ca2+, NO3-, Cl- and SO4(2-) on the photocatalytic degradation and decolorization reaction of MO was studied. The photocatalytic method was applied for the degradation of MO in several synthetic wastewater samples with satisfactory results

Flow injection determination of ultra trace amounts of rhodium(III) with spectrophotometric detection

222-224A flow injection method for determination for rhodium (III) has been developed based on its catalytic effect on the oxidation of Nile Blue by periodate at pH 9.20. The react ion was monitored spectrophotometrically at 630 nm. The effects of reagent concentration and manifold variables were studied and optimized. The method is linear in the range of 0.030-30.0 μg.ml-1 Rh(III).The effects of interfering ions on the determination of Rh(III) have been studied. The proposed method has been used for the determination of rhodium(III) in synthetic samples with satisfactory results

Clean and Green Synthesis of New Benzothiazole Derivatives via Electrochemical Oxidation of Catechol Derivatives

Electrochemical oxidation of the catechols 1a and 1b is studied in the presence of 6-methyl-2-thouracil (3b) and 6-propyl-2-thiouracil (3a) as nucleophiles in a phosphate buffer (0.15 mol L−1, pH = 6.8)/DMF (95:5) solution using cyclic voltammetry and controlled-potential coulometry. The results obtained indicate that the quinones derived from the catechols participate in 1,4-Michael-addition reactions with the nucleophiles to form the corresponding new benzothiazole compounds. In this work, we derive a variety of products with good yields using controlled potential at graphite electrodes in an undivided cell. <br><a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/80x15.png" /></a> This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>

Determination of copper(II) by flame atomic absorption spectrometry after its perconcentration by a highly selective and environmentally friendly dispersive liquid–liquid microextraction technique

Abstract A new, simple, rapid, selective, and environmentally friendly method is proposed for the determination of Cu(II) ions based on the formation of the complex between these ions and salophen as the ligand followed by the dispersive liquid–liquid microextraction of the neutral hydrophobic complex formed in the organic phase and flame atomic absorption spectrophotometric detection. Various factors including the pH of the sample solution, concentration of salophen as the complexing reagent, type and volume of the extraction and disperser solvents, and extraction time affecting the extraction efficiency of Cu(II) ions and its subsequent analytical signal were studied and optimized. Under the optimized experimental conditions, the detection limit (3σ) and the enrichment factor were obtained to be 0.60 μg L−1 and 49, respectively, for 10.0 mL of the sample solution. The consumptive index was 0.20 mL and the calibration graph was linear in the range of 3.0–120 μg L−1. The relative standard deviations for six replicate measurements of 5.0, 20.0, and 50.0 μg L−1 of Cu(II) ions were 4.1%, 1.5%, and 1.8%, respectively. The proposed method was also successfully applied for the extraction and determination of Cu(II) ions in different water and food samples with satisfactory results

(E)-2-{N-Ethyl-4-[(4-nitrophenyl)diazenyl]anilino}ethyl acrylate

In the molecule of the title compound, C19H20N4O4, the rings are almost coplanar, forming a dihedral angle of 0.76&#8197;(3)&#176;. In the crystal structure, intermolecular C&#8212;H...O hydrogen bonds link the molecules