Determination of lead in metallic reference materials by laser ablation combined with laser excited atomic fluorescence

Concentrations of lead in the range 0.15–750 μg⁻¹ were measured in metallic matrices (copper, brass, steel, and zinc) by laser excited atomic fluorescence combined with UV laser ablation in a low-pressure (130 mbar) argon atmosphere. The mass of material ablated was determined by repetitive weighing of the target prior to and after approximately 10 000 ablating shots. The fluorescence was excited after a 100 μs delay relative to the ablation pulse. A long integration time of 200 s was used to provide a representative determination of bulk concentrations. No matrix effect was observed, providing a universal calibration curve for all samples with relative standard deviations of about 20%. The relative and absolute limits of detection were 72 ng g⁻¹ and 0.5 fg, respectively.     

Instrumental neutron activation analysis of manganese,copper and vanadium in some commercial steel samples and of copper in copper base alloys

The instrumental neutron activation analysis (INAA) of industrially important steel samples, viz. IS-226, IS-2002, IS-2062, SS-304, SS-310, SS-316 and of copper base alloys, viz. high brass, gun metal and copper-silver alloys is carried out with a 2 Ci²⁵²Cf neutron source. The copper and vanadium content of all the steel samples and manganese content of former three steel samples are estimated by measuring the gamma activity of⁶⁶Cu,⁵²V and⁵⁶Mn radioisotopes, respectively, using a high purity germanium (HPGe) detector coupled to a 4 K multichannel analyzer (MCA). Similarly, the copper content of copper base alloys was also determined.Dedicated to Prof. H. J. Arnikar, Professor Emeritus, University of Poona, on the occasion of his 75th birthday.     

Synthesis,crystal structures,and urease inhibition studies of two new Schiff-base copper complexes derived from n-butylamine

Two Schiff-base copper(II) complexes, bis(N-n-butyl-5-chlorosalicylaldiminato) copper(II) (1) and bis(N-n-butyl-4-methoxysalicylaldiminato) copper(II) (2), were synthesized and their solid-state structures were determined by X-ray crystallography. Complex 1 displays a distorted square-planar geometry, while 2 possesses square-planar geometry. Copper(II) complexes 1 and 2 showed strong inhibitory activity against jack bean urease (IC₅₀?=?2.7, 3.5?µmol?L^?1), compared with acetohydroxamic acid (IC₅₀?=?63.00?µmol?L^?1). A molecular modeling study was carried out via the DOCK program to gain understanding of the potent inhibitory activity of these copper species against jack bean urease.     

Use of an Impaction-Electrothermal Atomization Atomic Absorption Spectrometric System for the Direct Determination of Cadmium,Copper, and Manganese in the Laboratory Atmosphere

Abstract

Results on an impaction-electrothermal atomization atomic absorption spectrometric system for the direct, and on a nearly real-time basis, determination of cadmium, copper, and manganese in the laboratory atmosphere are presented. Background levels for cadmium were 3 ng m^?3, for copper were 100 ng m^?3, and for manganese were 30 ng m^?3 and were found to increase with activity in the vicinity of the system. Addition of a connecting faceplate to the impactor allowed a more convenient and accurate method of standardization to be achieved.     

Synthesis and solid state structures of two new copper(II) complexes of Schiff bases derived from furfuryl and tetrahydrofurfurylamine

Two Schiff base copper(II) complexes, bis(N-furfurylsalicylaldiminato)copper(II) (I) and bis(N-tetrahydrofurfurylsalicylaldiminato)copper(II) (II), were synthesized and their solid state structures were determined by X-ray crystallography. Complex I has a square planar geometry. In contrast, complex II displays a distorted square planar geometry. Thus, the geometry around copper in the solid state structures of I and II is determined by a combination of steric and electronic effects, as well as by crystal packing forces.     

Numerical and experimental depth profile analyses of coated and attached layers by laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is applied for depth profile analysis of different thicknesses of copper foils attached on steel and aluminum substrates. In order to account interfacial effects, depth profile analysis of copper coated on steel is also carried out. Experiments are done at ambient air and at two different wavelengths of 266 and 1064 nm of a Nd:YAG laser with pulse durations of 5 ns. A three-dimensional model of multi-pulse laser ablation is introduced on the base of normal evaporation mechanism and the simulation results are compared with the experiments. A normalized concentration (C^N) is introduced for determination of interface position and results are compared with the usually used normalized intensity (I^N). The effect of coating thickness on average ablation rate and resolution of depth profiling are examined. There is a correlation coefficient higher than 0.95 between the model and experimental depth profiles based on the C^N method. Depth profile analysis on the base of C^N method shows a better depth resolution in comparison with I^N method .Increase in the layer thickness, leads to a decrease in the ablation rate.     

Template-directed synthesis of macrocyclic copper(II) complexes of diazacyclam, 1,3,6,10,12,15-hexaazatricyclo[13.3.1.16,10]eicosane

Template reaction of copper(II) nitrate with N-(2-aminoethyl)-1,3-diaminopropane and formaldehyde yields a macrocyclic copper(II) complex of 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1^6,10]eicosane (L), [CuL(NO₃)₂] (1). Replacement of nitrate with perchlorate gives [CuL(ClO₄)₂] (2). These complexes have been characterized by FT-IR and Raman spectroscopies, electronic absorption, cyclic voltammetry, and X-ray crystallography. The crystal structure of 1 shows that copper has distorted octahedral geometry with two secondary and two tertiary amines of the macrocycle and two oxygen atoms from nitrate coordinating the axial positions. The copper in 2 has the same geometry with axial positions occupied by one oxygen atom of perchlorate. Copper lies on the plane of four coordinated nitrogen atoms and there is no rms deviation from this plane. Cyclic voltammetry of 1 and 2 gives two one-electron waves corresponding to Cu^II/Cu^III (?0.75,??0.72) and Cu^II/Cu^I (0.48, 0.24) processes. For understanding of geometry parameters in diazacyclam-based copper(II) complexes, a survey on complexes from CSD structures is presented. In this study the macrocycle hole size was estimated by ionic radii of metal ions located inside of it.     

Composition and Homogeneity of Nb<Subscript>2</Subscript>O<Subscript>5</Subscript>〈В〉 Solid Precursors and LiNbO<Subscript>3</Subscript>〈В〉 Batches

Nb₂O₅〈В〉 solid precursors and LiNbO₃〈В〉 batches prepared on their basis, which can be used for preparing optical-quality lithium niobate single crystals and pore-free piezoelectric ceramics, have been studied by laser ablation inductively coupled mass spectrometry (LA-ICP-MS). The compositions of powdery samples pelletized without binder have been determined. The calculated mean-square deviations Sr of laser ablation ICP-MS have been used to show a homogeneous distribution of the boron dopant over Nb₂O₅〈В〉 precursors and LiNbO₃〈В〉 batches.     

Synthesis,spectroscopic characterization,antimicrobial activity and crystal structure of silver and copper complexes of sulfamethazine

Silver(I) and copper(II) complexes of 4-amino-N-(4,6-dimethyl-2-pyrimidinyl) benzenesulfonamide (smz) have been synthesized and characterized by elemental analysis and infrared (IR), ¹H NMR, and UV–vis spectroscopy. [Ag(smz)(pyridine)] (1) crystallizes in monoclinic system with space group P2₁/c and Z = 4, while [Cu(smz)₂(pyridine)₂]·H₂O (2) crystallizes in triclinic system with space group P-1 and Z = 2. X-ray analysis revealed that silver in 1 is four-coordinate exhibiting distorted tetrahedral geometry, while copper in 2 is coordinated to six nitrogens leading to a highly distorted octahedral geometry. The molecular structures of both 1 and 2 are stabilized by N–H?O and C–H?π intermolecular and C–H?O intramolecular interactions. Water plays a significant role in crystal packing by forming strong N–H?O_water intramolecular as well as O_water–H?N intermolecular interactions in 2. The results of IR, UV–vis, ¹H NMR spectral data and thermal analysis for 1 and 2 suggest that the binding of silver and copper to the sulfonamidic nitrogen is in agreement with the crystal structure determination. Antimicrobial activities of silver (1) and copper (2) complexes of sulfamethazine are studied by the dilution method against Staphylococcus aureus and Escherichia coli strains.     

Evaluation and Application of the Internal Standard Technique for the Direct Determination of Copper in Fruit Juices Employing Fast Sequential Flame Atomic Absorption Spectrometry

Abstract

The present paper describes the evaluation and application of internal standard for the determination of copper in fruit juices, employing Fast Sequential Flame Atomic Absorption Spectrometry (FS FAAS). The internal standards tested were indium, cobalt, and nickel using correlation graphs. However, indium was used, considering the composition of the samples. After this step, copper was determined in fruit juices using indium as internal standard. This method allows the determination of copper with a limit of quantification of 0.011 mg L^?1. The fruit juice samples selected for analysis were of grape, orange, pineapple, peach, cashew, and strawberry. The contents of copper in these samples varied from 0.02 to 0.42 mg L^?1. The analytical results were compared with the results obtained by analysis of these samples after complete mineralization using acid digestion and determination employing FS FAAS. The statistical comparison by a t-test (95% confidence level) showed no significant difference between the results. The relative standard deviations (RSD) with and without the use of the internal standard for a copper solution containing 0.4 mg L^?1 were of 0.62 and 1.94%, respectively. The use of indium as internal standard provided more accurate analytical results, as well as better analytical performance for the determination of copper in juice samples.     

Extraction,Spectrophotometric and Atomic Absorption Spectrophotometric Determination of Molybdenum with Caffeic Acid and Application in High Purity Grade Steel and Environmental Samples

Abstract

A new selective and sensitive method for extraction of yellow Mo (VI)-caffeic acid complex with a liquid ion exchanger, Aliquat 336 from 4.0 pH, and spectrophotometric determination of molybdenum in trace amounts is described. the molar absorptivity of the complex is 1.1 × 10⁵ 1 mol^?1 cm^?1 at 340 nm and the colour system obeys Beer's law in the range 0.04–0.99 ppm of Mo(VI). the molybdenum is also determined with AAS and the method is applied for its determination in steel and environmental samples.     

Synthesis and characterization of [Cu(Phca2en)(PPh3)X] (X=Cl, Br, I, NCS, N3) complexes: crystal structures of [Cu(Phca2en)(PPh3)Br] and [Cu(Phca2en)(PPh3)I]

New mixed-ligand copper(I) complexes, [Cu(Phca₂en)(PPh₃)X], [Phca₂en = N,N′-bis(β-phenylci-nnamaldehyde)-1,2-diiminoethane and X=Cl (1), Br (2), I (3), NCS (4), N₃ (5)] have been synthesized and characterized by various techniques. ¹H and ¹³C-NMR and IR spectral data of these copper(I) complexes are compared with the free ligand to elucidate some structural features. The structures of [Cu(Phca₂en)(PPh₃)Br] (2) and [Cu(Phca₂en)(PPh₃)I] (3) have been determined from single-crystal data showing that the coordination geometry around copper atom is a distorted tetrahedron. Furthermore, these Cu(I) complexes exhibit supramolecular motifs of the type multiple phenyl embraces resulting from attractive interactions between phenyl rings of PPh₃ moieties. The presence of the C–H…Cu weak intramolecular hydrogen bonds, due to the trapping of C–H bonds in the vicinity of the metal atoms, is also reported.     

N-COORDINATED COPPER(II) COMPLEXES WITH 2-S-METHYL-5,5-DIMETHYLIMIDAZOLIN-4-ONE (L). CRYSTAL STRUCTURE OF [CuL4H2O][CuCl4]

Abstract

The reaction between CuX₂ (X = Cl, Br, NO₃, ClO₄) and 2-S-methyl-5,5-dimethylimidazolin-4-one (L) yields complexes having stoichiometry CuL₂Cl₂ · 1/2H₂O (1), CuL₂Br₂ (2), CuL₄X₂ · 2H₂O [X = NO₃ (3), ClO₄ (4)]. The X-ray crystal structure solved for 1 showed that it contains discrete [CuL₄ · H₂O]²⁺ and [CuCl₄]^2- ions, separated by normal van der Waals contacts. The [CuL₄H₂O]²⁺ cation has crystallographic C ₄ symmetry, with the copper atom and the oxygen of the water molecule lying on a four-fold axis of the space group P4/n and the metal atom in a square-pyramidal coordination geometry, obtained by a square basal plane defined by four N atoms and the apex occupied by the water molecule. The [CuCl₄]^2- anion shows a very flattened tetrahedral geometry. FT-IR and FT-Raman spectra of 1–4 show that 2,3 and 4 also are N(3)-coordinated to copper; nitrate and perchlorate do not coordinate. The v(CuO) vibrations are present at about 380 cm^?1 for 3 and 4, while for 2 v(CuBr) are at 224 and 215 cm^?1. Esr data for 1–4 recorded on solid samples highlight a d_x ² - y² ground state for the cation of 1, 3, and 4 which is typical for tetragonally elongated monomeric copper(II) complexes. Compound 2 exhibits two couples of g values characteristic of two independent copper centres both with compressed tetrahedral geometry. The deconvoluted reflectance spectra of 1–4 substantially confirm the presence of CuN₄ and CuBr₄ chromophores in 2 and a trans-CuN₄O₂ chromophore in 3 and 4. For the latter complexes an orbital sequence d_{x² - y²} > d_xy > d_z² > d_xy, d_yz is also suggested on the basis of the similarity between L and imidazole type ligands.     

Determination of Hg from Cu concentrates by X-ray fluorescence through preconcentration on polyurethane foam

A methodology was developed for the separation and determination of microamounts of mercury from copper concentrate samples by wavelength dispersive X-ray fluorescence (WDXRF) after solid-phase extraction of mercury from iodide medium using polyurethane foam (PUF). The best sorption conditions for the Hg-KI-PUF system were settled using X-ray fluorescence technique after collection of ground PUF on a filter paper by vacuum filtration and direct measurement of the intensity signal of the sorbed mercury on PUF. The main parameters of sorption such as iodide concentration, pH, shaking time and sample dilution effect were studied. The system shows rapid kinetic sorption and maximum X-ray intensity signal was achieved after shaking for 2 min a 0.01 mol l⁻¹ iodide solution containing microamounts of mercury in the pH range from 1.0 to 9.0. Effective sorption up to a volume of 0.9 l allows preconcentration of mercury. A linear fit up to 50 μg mercury was obtained by the plot of the initial mercury mass in the bulk solution (0.5 l) vs. its respective XRF intensity signal measurement on ground PUF after the sorption process. The calibration sensitivity, quantification and detection limits found were 9.09 CPS μg⁻¹, 9.0 and 2.7 μg, respectively. The sorption of many elements was also evaluated under the best conditions. High concentrations of Cu(II) and Fe(III) interfere seriously. Mercury-selective separation could be achieved using citrate or EDTA as masking agent; no interference due to copper matrix samples was observed in citrate medium. This methodology was evaluated by recovery for mercury determination in copper concentrate ore samples supplied by a mining industry and copper sulfate salts; the results were between 98% and 106%.     

Preparation and Characterization of Some Novel Diphenylphosphine Hydrazones and Semicarbazones and Their Metal Complex Derivatives

Interaction of hydrazones and semicarbazones derivatives I _{a ? t} with diphenylchlorophosphine II , gave new compounds III _a?t , and their complexation ability towards various divalent metal acetates Mn(OAc)₂. 4H₂O, Co(OAc)₂. 4H₂O, Ni(OAc)₂. 4H₂O, and Cu(OAc)₂. H₂O, in organic solvents are described. The metal/ phosphorsemi-carbazones ratios are measured and the results discussed. All these complexes are insoluble in organic solvents and in water. The structures of the isolated products were proposed on the basis of microanalyical data, TGA, IR, (UV/ VIS), (MS), and ¹H, ¹³C, and ³¹P-NMR spectroscopic analyses and magnetic susceptibility. The proposed structure of the complexes is based on a 1: 2 metal: ligand ratio. All of the complexes are found to have an octahedral geometry, with the exception of the square planar copper (II) complexes. The corrosion inhibition of aluminium and copper in 1 M HCl and chromium–nickel steel in crude oil using III_n have been studied by weight loss method.     

Structural conversion of an oxazolidine ligand upon treatment with copper(I) and (II) halides; structural,spectral, theoretical and docking studies

Abstract

In this work, the 2-(2-(pyridin-2-yl)oxazolidin-3-yl)ethanol (AEPC) ligand was prepared under solvent free conditions using ultrasonic irradiation, before reaction with a Cu(NO₃)₂/KSCN mixture, CuCl₂ and CuI, the products of which were characterized by elemental analysis, UV-Vis, FT-IR spectroscopy and single-crystal X-ray diffraction. The X-ray analyses results revealed that AEPC, after reactions with the three copper(I/II) halides, gave structures ([Cu(DEA)Cl₂] (2), DEA?=?diethanolamine, [Cu(BHEG)₂] (3), BHEG?=?bis(2-hydroxyethyl)glycinato); however, it retains its structure on treatment with Cu(NO₃)₂/KSCN mixture ([Cu(AEPC)(NCS)₂] (1)). The geometrical parameters for the complexes were compared with the Cambridge Structural Database (CSD) and coordination modes for thiocyanate ion were extracted. In the crystal structure of 1, the copper ion has a distorted square-pyramidal geometry and a CuN^pyN₂^NCSN^tertO^alc environment in which the AEPC acts as NN'O-donor in a facial coordination mode. In the crystal structure of 2, the copper ion has a Cu(N^sec)(O^alc)₂Cl₂ environment and distorted square-pyramidal geometry in which the DEA ligand is coordinated as a mer-NO₂-donor. The copper ion in 3 has a CuN₂O₄ environment and distorted octahedral geometry. The ability of these compounds to interact with the nine biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS and Top II) was investigated by Docking calculations and compared with that of doxorubicin. The thermodynamic stability of 1 and its isomer and also charge distribution patterns were studied by DFT and NBO analysis, respectively.     

Indirect Spectrophotometric Determination of Vanadium(IV) by Flow Injection Analysis Based on the Redox Reaction with Copper(II) in the Presence of Neocuproine

Abstract

An indirect photometric method with a continuous-flow analysis is presented for the determination of trace amounts of vanadium(IV). It is based on the redox reaction of copper(II) with vanadium(1V) in the presence of neocuproine. In the presence of neocuproine, copper(I1) is reduced easily by vanadium(I V) to a copper(1)-neocuproine complex, which shows a n absorption maximum at 454 nm. By measuring t h e absorbance of the complex at this wavelength, vanadium(1V) in t h e range 2×10^?6 - 8 × mol dm^?5 mol dm^?3 can be determined at a rate of 120 samples h^?1. The fractional determination of vanadium(1V) and iron(I1) is also studied.     

An Atomic Absorption Analysis Method for Cyanide

Abstract

An atomic absorption analysis procedure for cyanide has been developed. The procedure is based upon the solubilization of copper(II) from a basic copper carbonate in an alkaline medium. The amount of copper complexed by the cyanide ion is determined by atomic absorption and a calibration curve is constructed concurrently. The stoichiometry of the cyanide-copper complex is 3:1, implying formation of the complex ion Cu(CN)^? ₃, with no formation of CuCN observed at the low concentration of cyanide used. The method is used primarily for analyzing low levels of cyanide; the sensitivity of the method extending down to 2.0 × 10^?5 M CN^?. The most likely interference, iron, is considered. Finally, recovery of cyanide from spiked samples is demonstrated.     

Theoretical,antimicrobial, antioxidant,in vitro cytotoxicity,and cyclin-dependent kinase 2 inhibitor studies of metal(II) complexes with bis(imidazol-1-yl)methane-based heteroscorpionate ligands

Abstract

A series of C-centered heteroscorpionate-based homoleptic manganese(II), nickel(II), and copper(II) complexes of type [M(L^1–3)₂] (1–9) have been synthesized by using the ligands (2-hydroxyphenyl)bis(imidazol-1-yl)methane (HL¹), (4-diethylamino-2-hydroxyphenyl)bis(imidazol-1-yl)methane (HL²) and (5-bromo-2-hydroxyphenyl)bis(imidazol-1-yl)methane (HL³). The geometric parameters of the complexes were determined using UV-vis and theoretical studies suggesting distorted octahedral geometry around metal(II) ion. Frontier molecular orbital analysis supports bioefficacy of the complexes. Antimicrobial activity of the metal(II) complexes were determined against two Gram(–ve) (Escherichia coli and Klebsiella pneumoniae) and two Gram(+ve) (Bacillus cereus and Staphylococcus aureus) bacteria, and three fungal (Candida albicans, Candida glabrata, and Candida krusei) strains. Antioxidant activity of nickel(II) and copper(II) complexes were evaluated against ABTS, DPPH, and H₂O₂ free radicals. In vitro cytotoxicity activity of nickel(II) and copper(II) complexes against human breast adenocarcinoma (MCF-7), cervical (HeLa), and lung (A549) cancer cell lines along with one normal human dermal fibroblasts (NHDF) cell line were carried out by MTT assay, which shows the potent activity of copper(II) complex 8 with respect to the standard drug cisplatin. Molecular docking studies evidence the interaction of complexes with cyclin-dependent kinase 2 receptor (CDK2).     

Spectrophotometric Determination of Copper(II) as the Azide Complexes,in the Presence of Iron(III) Cations

Abstract

A method for the spectrophotometrio determination of copper(II), in the presence of iron(III) cations (excess), was stablished. The masking of iron is made with sodium fluoride salt in 50 % (v/v) water/acetone medium. In the recommended conditions, absorbances for cupric complexes are measured at 435 nm where molar absorptivity is 6.00 × 10³ 1 mol^?1 cm^?1.

The stable ayetern obeys Beer's law and is suitable for the copper determination in concentration range from 2.0 to 9.0 mg 1^?l. The iron(III) ion interference (until ca. 600 mg 1^?l) can be completely suppressed. The influence of diverse ions and several others factore were studied.

The results show that copper(II) can be accurately determined by azide apectrophotometric method, if the samples were suitablely treated by the recommended procedure.